Discussion:
1973 Honda CB350 - how much power?
(too old to reply)
Ig
2007-03-13 05:17:31 UTC
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Greetings. I have a general question and very much grateful for any
feedback.
I have recently moved from the flat midwest to the hilly san francisco
area.
I found a beautiful deal on a 73 Honda cb350... I realize that these
engines need constant tinkering. that is not the problem, this one has
low milage and lots of life still left.
My question is whether a 350 engine can generate enough juice to be
more than just a recreational bike. I would love to become the owner
of this if it can actually be expected to climb some hills (and even
carry a pasenger). Is this just wishful thinking?
Back in chicago i was riding a 76 CB750.. Not looking for lots of of
power necessarily, just functionality. what do you think?
Thanks in advance.
IR
Ian Singer
2007-03-13 05:49:46 UTC
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Ig wrote:
> Greetings. I have a general question and very much grateful for any
> feedback.
> I have recently moved from the flat midwest to the hilly san francisco
> area.
> I found a beautiful deal on a 73 Honda cb350... I realize that these
> engines need constant tinkering. that is not the problem, this one has
> low milage and lots of life still left.
> My question is whether a 350 engine can generate enough juice to be
> more than just a recreational bike. I would love to become the owner
> of this if it can actually be expected to climb some hills (and even
> carry a pasenger). Is this just wishful thinking?
>
In 1968 I had a CB160 that was 16HP. It was big enough for the freeways
and I drove from California to Alabama with no problems, and it was no
problem full throttle all day. The only problem was when I had it bored
to 175cc and the shop that installed the high compression cam left the
original valves springs in, as well as adding the new ones, so the
rocker arms chewed the cams up.

Now my Honda 50 was a different matter as it always slowed climbing
hills. On the 160 though I used to try for double the speed limit, plus
5 and I never could quite get it to 75MPH before I had to brake.

Ian Singer

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The Older Gentleman
2007-03-13 07:34:10 UTC
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Ig <***@gmail.com> wrote:

> My question is whether a 350 engine can generate enough juice to be
> more than just a recreational bike. I would love to become the owner
> of this if it can actually be expected to climb some hills (and even
> carry a pasenger).

Yes

>Is this just wishful thinking?

No



--
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GAGARPHOF#30 GHPOTHUF#1 BOTAFOT#60 ANORAK#06 YTC#3
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.***@see_my_sig_for_address.com
2007-03-13 13:27:21 UTC
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On 12 Mar 2007 22:17:31 -0700, "Ig" <***@gmail.com> wrote:

>Greetings. I have a general question and very much grateful for any
>feedback.
>I have recently moved from the flat midwest to the hilly san francisco
>area.
>I found a beautiful deal on a 73 Honda cb350... I realize that these
>engines need constant tinkering. that is not the problem, this one has
>low milage and lots of life still left.
>My question is whether a 350 engine can generate enough juice to be
>more than just a recreational bike. I would love to become the owner
>of this if it can actually be expected to climb some hills (and even
>carry a pasenger). Is this just wishful thinking?
>Back in chicago i was riding a 76 CB750.. Not looking for lots of of
>power necessarily, just functionality. what do you think?
>Thanks in advance.
>IR

34 HP. You're not really gonna want to climb hills or carry
passengers on it too often.


--
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Paul ( pjm @ pobox . com ) - remove spaces to email me
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The Older Gentleman
2007-03-13 19:45:25 UTC
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<***@see_my_sig_for_address.com> wrote:

> On 12 Mar 2007 22:17:31 -0700, "Ig" <***@gmail.com> wrote:
>
> >Greetings. I have a general question and very much grateful for any
> >feedback.
> >I have recently moved from the flat midwest to the hilly san francisco
> >area.
> >I found a beautiful deal on a 73 Honda cb350... I realize that these
> >engines need constant tinkering. that is not the problem, this one has
> >low milage and lots of life still left.
> >My question is whether a 350 engine can generate enough juice to be
> >more than just a recreational bike. I would love to become the owner
> >of this if it can actually be expected to climb some hills (and even
> >carry a pasenger). Is this just wishful thinking?
> >Back in chicago i was riding a 76 CB750.. Not looking for lots of of
> >power necessarily, just functionality. what do you think?
> >Thanks in advance.
> >IR
>
> 34 HP. You're not really gonna want to climb hills or carry
> passengers on it too often.

*Shrug*. I dunno. Given US sped limits, if you cruise it at 65mph it
should be fine.


--
BMW K1100LT 750SS CB400F CD250 Z650
GAGARPHOF#30 GHPOTHUF#1 BOTAFOT#60 ANORAK#06 YTC#3
BOF#30 WUSS#5 The bells, the bells.....
.***@see_my_sig_for_address.com
2007-03-13 21:04:37 UTC
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On Tue, 13 Mar 2007 19:45:25 +0000,
***@dsl.pipex.com (The Older Gentleman) wrote:

><***@see_my_sig_for_address.com> wrote:
>
>> On 12 Mar 2007 22:17:31 -0700, "Ig" <***@gmail.com> wrote:
>>
>> >Greetings. I have a general question and very much grateful for any
>> >feedback.
>> >I have recently moved from the flat midwest to the hilly san francisco
>> >area.
>> >I found a beautiful deal on a 73 Honda cb350... I realize that these
>> >engines need constant tinkering. that is not the problem, this one has
>> >low milage and lots of life still left.
>> >My question is whether a 350 engine can generate enough juice to be
>> >more than just a recreational bike. I would love to become the owner
>> >of this if it can actually be expected to climb some hills (and even
>> >carry a pasenger). Is this just wishful thinking?
>> >Back in chicago i was riding a 76 CB750.. Not looking for lots of of
>> >power necessarily, just functionality. what do you think?
>> >Thanks in advance.
>> >IR
>>
>> 34 HP. You're not really gonna want to climb hills or carry
>> passengers on it too often.
>
>*Shrug*. I dunno. Given US sped limits, if you cruise it at 65mph it
>should be fine.

Just my recollection of my CB360 from that time.



--
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Paul ( pjm @ pobox . com ) - remove spaces to email me
'Some days, it's just not worth chewing through the restraints.'
'With sufficient thrust, pigs fly just fine.'
HVAC/R program for Palm PDA's
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Ig
2007-03-14 02:30:52 UTC
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Thank you all for your feedback. Sounds like it's more than just a
scooter !
Zaphod Beeblebrock
2007-03-14 14:24:09 UTC
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On Tue, 13 Mar 2007 16:04:37 -0500, wrote:

> On Tue, 13 Mar 2007 19:45:25 +0000,
> ***@dsl.pipex.com (The Older Gentleman) wrote:
>
>><***@see_my_sig_for_address.com> wrote:
>>
>>> On 12 Mar 2007 22:17:31 -0700, "Ig" <***@gmail.com> wrote:
>>>
>>> >Greetings. I have a general question and very much grateful for any
>>> >feedback.
>>> >I have recently moved from the flat midwest to the hilly san francisco
>>> >area.
>>> >I found a beautiful deal on a 73 Honda cb350... I realize that these
>>> >engines need constant tinkering. that is not the problem, this one has
>>> >low milage and lots of life still left. My question is whether a 350
>>> >engine can generate enough juice to be more than just a recreational
>>> >bike. I would love to become the owner of this if it can actually be
>>> >expected to climb some hills (and even carry a pasenger). Is this just
>>> >wishful thinking? Back in chicago i was riding a 76 CB750.. Not
>>> >looking for lots of of power necessarily, just functionality. what do
>>> >you think? Thanks in advance.
>>> >IR
>>>
>>> 34 HP. You're not really gonna want to climb hills or carry
>>> passengers on it too often.
>>
>>*Shrug*. I dunno. Given US sped limits, if you cruise it at 65mph it
>>should be fine.
>
> Just my recollection of my CB360 from that time.


I've owned a couple of the early '70s CL360s and, after a bit of
tinkering[1], could get them up past 120mph. Carrying a passenger was
never a problem either...but, I only weigh about 140lbs and it doesn't
take too many horses to pull my bean-pole bod down the road.
(Unfortunately, even at that light weight they don't fly very well, even
at 120+mph, after leaving said road on a banked curve. They aren't much
good for riding on afterward, either.)

[1]The tinkering was mostly just fine-tuning the motor and changing the
rear sprocket and the chain.


--
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chateau.murray@btinternet.com,
2007-03-14 16:08:51 UTC
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On 14 Mar, 15:24, Zaphod Beeblebrock
<***@TheUniverseTheRestaurant.com> wrote:
>
> I've owned a couple of the early '70s CL360s and, after a bit of
> tinkering[1], could get them up past 120mph. Carrying a passenger was
> never a problem either...but, I only weigh about 140lbs and it doesn't
> take too many horses to pull my bean-pole bod down the road.
> (Unfortunately, even at that light weight they don't fly very well, even
> at 120+mph, after leaving said road on a banked curve. They aren't much
> good for riding on afterward, either.)
>
> [1]The tinkering was mostly just fine-tuning the motor and changing the
> rear sprocket and the chain.
>

Blimey. To get a 360 to that sort of speed would need booster rckets,
I'd have thought.

I've alway liked the style of the CL series. Shame we never got them
in the UK, although there are quite a few that have been re-imported
from the States.
Mark Olson
2007-03-14 16:21:39 UTC
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***@btinternet.com wrote:
> On 14 Mar, 15:24, Zaphod Beeblebrock
> <***@TheUniverseTheRestaurant.com> wrote:
>
>>I've owned a couple of the early '70s CL360s and, after a bit of
>>tinkering[1], could get them up past 120mph. Carrying a passenger was
>>never a problem either...but, I only weigh about 140lbs and it doesn't
>>take too many horses to pull my bean-pole bod down the road.
>>(Unfortunately, even at that light weight they don't fly very well, even
>>at 120+mph, after leaving said road on a banked curve. They aren't much
>>good for riding on afterward, either.)
>>
>>[1]The tinkering was mostly just fine-tuning the motor and changing the
>>rear sprocket and the chain.
>>
>
>
> Blimey. To get a 360 to that sort of speed would need booster rckets,
> I'd have thought.

This sounds suspiciously like the guy who claimed he got his stock CB900C
to 160 mph just by carefully tweaking the carbs. When a couple of people
told him he was dreaming he got a bit upset.

http://groups.google.com/group/rec.autos.makers.ford.explorer/msg/c5f68da7d54905d0

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chateau.murray@btinternet.com,
2007-03-14 17:19:43 UTC
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On 14 Mar, 17:21, Mark Olson <***@tiny.invalid> wrote:
> ***@btinternet.com wrote:
> > On 14 Mar, 15:24, Zaphod Beeblebrock
> > <***@TheUniverseTheRestaurant.com> wrote:
>
> >>I've owned a couple of the early '70s CL360s and, after a bit of
> >>tinkering[1], could get them up past 120mph. Carrying a passenger was
> >>never a problem either...but, I only weigh about 140lbs and it doesn't
> >>take too many horses to pull my bean-pole bod down the road.
> >>(Unfortunately, even at that light weight they don't fly very well, even
> >>at 120+mph, after leaving said road on a banked curve. They aren't much
> >>good for riding on afterward, either.)
>
> >>[1]The tinkering was mostly just fine-tuning the motor and changing the
> >>rear sprocket and the chain.
>
> > Blimey. To get a 360 to that sort of speed would need booster rockets,
> > I'd have thought.
>
> This sounds suspiciously like the guy who claimed he got his stock CB900C
> to 160 mph just by carefully tweaking the carbs. When a couple of people
> told him he was dreaming he got a bit upset.
>
> http://groups.google.com/group/rec.autos.makers.ford.explorer/msg/c5f...
>

Heh. Yes, exactly the same. My old CB360 would do about 95+ indicated,
flat out. To get one to do a genuine 120mph would require serious deep
surgery. And a tuned speedometer as well. The old SOHC 750s would just
about hit 120 on a good day, but most of the time 110-115 was your
lot. No way would a 360 twin get anywhere near that speed.
.***@see_my_sig_for_address.com
2007-03-14 18:34:17 UTC
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On 14 Mar 2007 10:19:43 -0700, ***@btinternet.com,
<***@btinternet.com> wrote:

>On 14 Mar, 17:21, Mark Olson <***@tiny.invalid> wrote:
>> ***@btinternet.com wrote:
>> > On 14 Mar, 15:24, Zaphod Beeblebrock
>> > <***@TheUniverseTheRestaurant.com> wrote:
>>
>> >>I've owned a couple of the early '70s CL360s and, after a bit of
>> >>tinkering[1], could get them up past 120mph. Carrying a passenger was
>> >>never a problem either...but, I only weigh about 140lbs and it doesn't
>> >>take too many horses to pull my bean-pole bod down the road.
>> >>(Unfortunately, even at that light weight they don't fly very well, even
>> >>at 120+mph, after leaving said road on a banked curve. They aren't much
>> >>good for riding on afterward, either.)
>>
>> >>[1]The tinkering was mostly just fine-tuning the motor and changing the
>> >>rear sprocket and the chain.
>>
>> > Blimey. To get a 360 to that sort of speed would need booster rockets,
>> > I'd have thought.
>>
>> This sounds suspiciously like the guy who claimed he got his stock CB900C
>> to 160 mph just by carefully tweaking the carbs. When a couple of people
>> told him he was dreaming he got a bit upset.
>>
>> http://groups.google.com/group/rec.autos.makers.ford.explorer/msg/c5f...
>>
>
>Heh. Yes, exactly the same. My old CB360 would do about 95+ indicated,

Mine did > 100 ( barely ), given a really long downhill and a
sufficient tailwind ;-)

>flat out. To get one to do a genuine 120mph would require serious deep
>surgery. And a tuned speedometer as well. The old SOHC 750s would just
>about hit 120 on a good day, but most of the time 110-115 was your
>lot. No way would a 360 twin get anywhere near that speed.


--
Click here every day to feed an animal that needs you today !!!
http://www.theanimalrescuesite.com/

Paul ( pjm @ pobox . com ) - remove spaces to email me
'Some days, it's just not worth chewing through the restraints.'
'With sufficient thrust, pigs fly just fine.'
HVAC/R program for Palm PDA's
Free demo now available online http://pmilligan.net/palm/
Zaphod Beeblebrock
2007-03-15 18:57:30 UTC
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On Wed, 14 Mar 2007 10:19:43 -0700, chateau.murray wrote:

> On 14 Mar, 17:21, Mark Olson <***@tiny.invalid> wrote:
>> ***@btinternet.com wrote:
>> > On 14 Mar, 15:24, Zaphod Beeblebrock
>> > <***@TheUniverseTheRestaurant.com> wrote:
>>
>> >>I've owned a couple of the early '70s CL360s and, after a bit of
>> >>tinkering[1], could get them up past 120mph. Carrying a passenger was
>> >>never a problem either...but, I only weigh about 140lbs and it doesn't
>> >>take too many horses to pull my bean-pole bod down the road.
>> >>(Unfortunately, even at that light weight they don't fly very well,
>> >>even at 120+mph, after leaving said road on a banked curve. They
>> >>aren't much good for riding on afterward, either.)
>>
>> >>[1]The tinkering was mostly just fine-tuning the motor and changing
>> >>the rear sprocket and the chain.
>>
>> > Blimey. To get a 360 to that sort of speed would need booster rockets,
>> > I'd have thought.
>>
>> This sounds suspiciously like the guy who claimed he got his stock
>> CB900C to 160 mph just by carefully tweaking the carbs. When a couple
>> of people told him he was dreaming he got a bit upset.
>>
>> http://groups.google.com/group/rec.autos.makers.ford.explorer/msg/c5f...
>>
>>
> Heh. Yes, exactly the same. My old CB360 would do about 95+ indicated,
> flat out. To get one to do a genuine 120mph would require serious deep
> surgery. And a tuned speedometer as well. The old SOHC 750s would just
> about hit 120 on a good day, but most of the time 110-115 was your lot. No
> way would a 360 twin get anywhere near that speed.


If you will think about it rationally for a moment gentlemen, before
simply *assuming* that I am exaggerating, consider what I said about
changing out the rear sprocket.

Picture a multi-speed bicycle with different sized sprockets on the front
and rear. Consider your legs to be the two cylinders. Pumping your legs at
a given rate (RPM) will propel you at a given speed. If you shift the rear
derailleur to a _smaller_ sprocket, then pumping your legs at the same
rate as before will propel you at a *faster* speed.

Granted, the smaller rear sprocket will change the torque(?) ratio, but at
my relatively light body weight the sacrifice is an acceptable trade-off
for the higher top speed.

There is nothing magical or delusional about this:

Smaller rear sprocket = higher top speed.


Now, if you would like to be helpful, I wouldn't mind a little advice on
performing a similar modification on my current machine. It is a '96
Yamaha Virago 1100 Special which produces *far* more horsepower than is
necessary to pull my skinny ass down the road.

This is the first bike I've owned with a shaft-drive. I am constantly
wishing it had a sixth gear in it. I'm not as much as a speed-freak as I
was when I was younger, I'd just like to lower the RPM for cruising and
improve the fuel milage...especially since it seems like the alcohol mix
I'm getting for fuel now has put a drastic hit on it. I used to be able to
get 165-170 miles before the low-fuel light would come on, I ran dry the
other day at 136mi.

I experienced the same phenomenon on a trip to Texas last year. Straight
regular gas gave me the expected milage, the alcohol mix reduced it,
requiring more frequent fuel stops.

I have my doubts about the feasibility of changing the gearing where the
shaft meets the rear axle, which means that I'd probably have to change
the transmission gears. Is either one of these ideas feasible, without
going to extreme effort or expense?

--
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The Older Gentleman
2007-03-15 19:05:25 UTC
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Zaphod Beeblebrock <***@TheUniverseTheRestaurant.com> wrote:

> If you will think about it rationally for a moment gentlemen, before
> simply *assuming* that I am exaggerating, consider what I said about
> changing out the rear sprocket.
>
> Picture a multi-speed bicycle with different sized sprockets on the front
> and rear. Consider your legs to be the two cylinders. Pumping your legs at
> a given rate (RPM) will propel you at a given speed. If you shift the rear
> derailleur to a _smaller_ sprocket, then pumping your legs at the same
> rate as before will propel you at a *faster* speed.
>

You stupid sod.

Have you ever thought why you sometimes need to change down a gear (or
two) on any vehicle, when (for example) climbing a hill?

It's because you don't have the power to pull a taller gear.

If simply gearing up an engine (or bicycle) was all it took to hit high
speed, every vehicle would travel at 500mph (or more).


> There is nothing magical or delusional about this:

Yes there is. You are delusional.


--
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GAGARPHOF#30 GHPOTHUF#1 BOTAFOT#60 ANORAK#06 YTC#3
BOF#30 WUSS#5 The bells, the bells.....
Zaphod Beeblebrock
2007-03-15 20:29:03 UTC
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On Thu, 15 Mar 2007 19:05:25 +0000, The Older Gentleman wrote:

> Zaphod Beeblebrock <***@TheUniverseTheRestaurant.com> wrote:
>
>> If you will think about it rationally for a moment gentlemen, before
>> simply *assuming* that I am exaggerating, consider what I said about
>> changing out the rear sprocket.
>>
>> Picture a multi-speed bicycle with different sized sprockets on the
>> front and rear. Consider your legs to be the two cylinders. Pumping your
>> legs at a given rate (RPM) will propel you at a given speed. If you
>> shift the rear derailleur to a _smaller_ sprocket, then pumping your
>> legs at the same rate as before will propel you at a *faster* speed.
>>
>>
> You stupid sod.


*Sigh*

I try to be polite, and what does it get me? My apologies, clearly I was
at least partially wrong in addressing my reply to "gentlemen".


> Have you ever thought why you sometimes need to change down a gear (or
> two) on any vehicle, when (for example) climbing a hill?
>
> It's because you don't have the power to pull a taller gear.


> If simply gearing up an engine (or bicycle) was all it took to hit high
> speed, every vehicle would travel at 500mph (or more).


Well, no shit, Sherlock.

Perhaps you misses the part where I addressed the trade-off in torque
ratio. Pull your head out of your ass, the lack of oxygen is killing your
brain cells.


--
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Zymurgical Alchemy
First Inter-Galactic Guild House Of
The Brotherhood Of St. Cathode Of Anode
Mark Olson
2007-03-15 20:34:03 UTC
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Zaphod Beeblebrock wrote:

> Perhaps you misses the part where I addressed the trade-off in torque
> ratio. Pull your head out of your ass, the lack of oxygen is killing your
> brain cells.

No, Zaphod, even allowing for your two heads, I doubt there's more
than an ounce of so of gray matter in total, if that. Stop digging,
you're in a hole, and you're just making yourself look *utterly*
stupid.

--
'01 SV650S '99 EX250-F13 '98 ZG1000-A13
OMF #7
Honest John
2007-03-15 21:23:54 UTC
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Hey, Zaphod.
Go easy on The-Older-Gentleman, He is just what his handle states. He is
a good guy and offers a ton of well thought out advise. I am glad to have a
more mature viewpoint from this mix of brains once in a while. His is just
that, mature.
I don't think he meant his remark to sound mean.

On the subject of the bike and uses you described:
I had an old tired one as well, years ago.
It might get you around, might climb the hills, but the level of comfort
will not be too good. As you ride more and more, you will build confidence
and abilities and I think you will grow bored with it's lack of power. You
just wont have much power in reserve for when you need it.
I think you might also conceder the physical size of the bike, it just
doesn't fit two people very well. You will find yourself sliding your butt
back some when riding solo. Then pick up your passenger and move forward for
her and suddenly feel how cramped the seating really is.

Just my 2 cents.
John
Zaphod Beeblebrock
2007-03-16 00:45:44 UTC
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On Thu, 15 Mar 2007 16:23:54 -0500, Honest John wrote:

> Hey, Zaphod.
> Go easy on The-Older-Gentleman, He is just what his handle states. He
> is
> a good guy and offers a ton of well thought out advise. I am glad to have
> a more mature viewpoint from this mix of brains once in a while. His is
> just that, mature.
> I don't think he meant his remark to sound mean.

I *was* trying to be polite, even in the face of
almost-but-not-quite being called a liar. It was the "You stupid sod" part
that kind of got my dander up. If that wasn't intended to be mean, then
perhaps I just took it the wrong way.

OK, I'll take your word for it and refrain from any further hostility. I'm
sure glad that I didn't send what I had written when I *first* started to
reply.


> On the subject of the bike and uses you described: I had an old tired one
> as well, years ago. It might get you around, might climb the hills, but
> the level of comfort will not be too good. As you ride more and more, you
> will build confidence and abilities and I think you will grow bored with
> it's lack of power. You just wont have much power in reserve for when you
> need it. I think you might also conceder the physical size of the bike, it
> just doesn't fit two people very well. You will find yourself sliding your
> butt back some when riding solo. Then pick up your passenger and move
> forward for her and suddenly feel how cramped the seating really is.

True enough on the fit. I've rather long legs and usually rode far back on
the seat. With a chick on the back it was quite uncomfortable. I have the
same problem, even on my Virago, and with the step seat it really isn't
conducive to sliding my butt backward for a better fit.


--
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Zymurgical Alchemy
First Inter-Galactic Guild House Of
The Brotherhood Of St. Cathode Of Anode
The Older Gentleman
2007-03-16 07:20:57 UTC
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Zaphod Beeblebrock <***@TheUniverseTheRestaurant.com> wrote:

> > If simply gearing up an engine (or bicycle) was all it took to hit high
> > speed, every vehicle would travel at 500mph (or more).
>
>
> Well, no shit, Sherlock.

It does seem to have eluded you, though.
>
> Perhaps you misses the part where I addressed the trade-off in torque
> ratio.

Bwaaahahahahaha!

Makes *no* difference whatsoever. Power is power, and if you don't have
enough power to pull a taller gear, not even dilithium crystals will
help.

I stand by my previous assessment. You are a stupid sod.



--
BMW K1100LT 750SS CB400F CD250 Z650
GAGARPHOF#30 GHPOTHUF#1 BOTAFOT#60 ANORAK#06 YTC#3
BOF#30 WUSS#5 The bells, the bells.....
Zaphod Beeblebrock
2007-03-16 14:51:03 UTC
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On Fri, 16 Mar 2007 07:20:57 +0000, The Older Gentleman wrote:

> Zaphod Beeblebrock <***@TheUniverseTheRestaurant.com> wrote:
>
>> > If simply gearing up an engine (or bicycle) was all it took to hit
>> > high speed, every vehicle would travel at 500mph (or more).
>>
>>
>> Well, no shit, Sherlock.
>
> It does seem to have eluded you, though.
>>
>> Perhaps you misses the part where I addressed the trade-off in torque
>> ratio.
>
> Bwaaahahahahaha!
>
> Makes *no* difference whatsoever. Power is power, and if you don't have
> enough power to pull a taller gear, not even dilithium crystals will help.
>
> I stand by my previous assessment. You are a stupid sod.

That motor had the power. And it wasn't a fluke, I did it to two different
CL360s and it didn't take a whole lot of work to do it.

I will respect the other gentleman's high opinion of you and not respond
in kind to your repeated insult, though I would have thought that if you
were truly the sort he claims you would have the wisdom not to maintain
such a stubbornly entrenched position. Just because *you* cannot conceive
how a thing can be done doesn't mean that it can't be done.

If you have taken the time to peruse the link that Mr. Cortese so kindly
provided, you will have seen that my paltry 120mph out of that particular
machine pales in comparison to what others have done.

While you're talking about power, consider that power alone is not the
only factor- there's the power-to-weight ratio.

As far as wind resistance- scootching back on the seat, feet on the rear
set of pegs and literally lying down on top of the fuel tank with elbows
tucked in cuts the drag considerably.

This conversation reminds me of a guy who swore up and down that it was
*impossible* to run a V-8 motor using three 2bbl carbs, even while looking
at the motor in operation.

You can continue calling me a "stupid sod" if you like, but I would
suggest that it may reflect more poorly on your character than mine.


--
Falcon's Rest
Zymurgical Alchemy
First Inter-Galactic Guild House Of
The Brotherhood Of St. Cathode Of Anode
chateau.murray@btinternet.com,
2007-03-16 15:27:43 UTC
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On 16 Mar, 15:51, Zaphod Beeblebrock
<***@TheUniverseTheRestaurant.com> wrote:
> On Fri, 16 Mar 2007 07:20:57 +0000, The Older Gentleman wrote:
> > Zaphod Beeblebrock <***@TheUniverseTheRestaurant.com> wrote:
>
>
> That motor had the power.

No, it didn't.

>And it wasn't a fluke, I did it to two different
> CL360s

No, you didn't.

> I will respect the other gentleman's high opinion of you and not respond
> in kind to your repeated insult, though I would have thought that if you
> were truly the sort he claims you would have the wisdom not to maintain
> such a stubbornly entrenched position. Just because *you* cannot conceive
> how a thing can be done doesn't mean that it can't be done.
>
> If you have taken the time to peruse the link that Mr. Cortese so kindly
> provided, you will have seen that my paltry 120mph out of that particular
> machine pales in comparison to what others have done.

As I said, for dedicated record-breaking or race machines. Different
animals. You've been told this, so I can only assume that you're
trying the point again out of desperation.

>
> While you're talking about power, consider that power alone is not the
> only factor- there's the power-to-weight ratio.

God, you are ignorant. Weight hardly affects top speed. It affects
acceleration. This was told you earlier in the thread.[1]

>
> As far as wind resistance- scootching back on the seat, feet on the rear
> set of pegs and literally lying down on top of the fuel tank with elbows
> tucked in cuts the drag considerably.

OK, sweetie. Do you know how motorcycle magazines achieve their top
speed figures? They get the smallest tester they can find, and dress
him in skin-tight leathers. Top speed runs are effected by doing
exactly what you say - flat on the tank, and with naked bikes, if you
dare, left hand off the bars and gripping the fork leg. Mirrors are
frequently removed.[2] And nope, no way will you get a CB360 to do 120
with the mods you suggested, unless you're going down a very, very
steep hill with a hurricane tailwind.

If a mag gets an utter max of 100mph, then the average Joe can expect
90+.

>
> This conversation reminds me of a guy who swore up and down that it was
> *impossible* to run a V-8 motor using three 2bbl carbs, even while looking
> at the motor in operation.

Not the same thing at all.

>
> You can continue calling me a "stupid sod" if you like, but I would
> suggest that it may reflect more poorly on your character than mine.
>

Nope, it's an accurate reflection of your intellect. Erring on the
kind side, if anything.

[1] More than 20 years ago, Bike magazine here in the UK did a very
interesting exercise involving (IIRC) a Honda VF400 and a number of
staff members, ranging from Roland Brown (then a staffer, now an
international freelance) who stood six feet four in his socks and
weighed 160lbs or so, and at the other end, editorial assistant Ione
Holmes (five feet one and 112lbs or so)[3]. Top speed runs,
electronically timed, were within a couple of mph of each other.
Quarter-mile times varied immensely, in favour of the small girl, who
had little experience of quarter-miling. I've got the copy in my
archive.
[2] Guess how I know this?
[3] They married each other, believe it or not.
Zaphod Beeblebrock
2007-03-17 18:36:22 UTC
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On Fri, 16 Mar 2007 08:27:43 -0700, chateau.murray wrote:

> On 16 Mar, 15:51, Zaphod Beeblebrock
> <***@TheUniverseTheRestaurant.com> wrote:
>> On Fri, 16 Mar 2007 07:20:57 +0000, The Older Gentleman wrote:


>> While you're talking about power, consider that power alone is not the
>> only factor- there's the power-to-weight ratio.
>
> God, you are ignorant. Weight hardly affects top speed. It affects
> acceleration. This was told you earlier in the thread.[1]

Which was my point. Perhaps you missed that part.

Given a machine designed to particular specifications for a particular
maximum load capacity, why don't you explain to my ignorant self just
exactly what happens if you change the gear ratio by reducing the size of
the rear sprocket say, from 48 teeth to 42 teeth, a reduction of roughly a
bit under 15 percent?

Will it hurt acceleration performance?

Will it increase top speed?

Suppose we reduce the max load by 50 percent,
how will this reduction affect acceleration performance?

Suppose we reduce the max load by another 50 percent,
for a total reduction of 75 percent, how will this affect
acceleration performance?

Is a 50 to 75 percent reduction in load sufficient
to offset, if not negate, the loss of acceleration
performance of the 15 percent reduction in the rear
sprocket?



--
Falcon's Rest
Zymurgical Alchemy
First Inter-Galactic Guild House Of
The Brotherhood Of St. Cathode Of Anode
Mark Olson
2007-03-17 19:15:43 UTC
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Zaphod Beeblebrock wrote:
> On Fri, 16 Mar 2007 08:27:43 -0700, chateau.murray wrote:
>>On 16 Mar, 15:51, Zaphod Beeblebrock
>><***@TheUniverseTheRestaurant.com> wrote:
>>>On Fri, 16 Mar 2007 07:20:57 +0000, The Older Gentleman wrote:

>>>While you're talking about power, consider that power alone is not the
>>>only factor- there's the power-to-weight ratio.
>>
>>God, you are ignorant. Weight hardly affects top speed. It affects
>>acceleration. This was told you earlier in the thread.[1]

> Which was my point. Perhaps you missed that part.

No, TOG didn't miss anything. Power/weight ratio is nearly meaningless
when you are concerned with top speed.

> Given a machine designed to particular specifications for a particular
> maximum load capacity, why don't you explain to my ignorant self just
> exactly what happens if you change the gear ratio by reducing the size of
> the rear sprocket say, from 48 teeth to 42 teeth, a reduction of roughly a
> bit under 15 percent?

On almost all bikes, all this will do is make it an absolute slug,
acceleration-wise.

> Will it hurt acceleration performance?

Without a doubt.

> Will it increase top speed?

Almost certainly not. Most bikes have their gearing set up so their
top speed is limited by the engine's maximum available power, that
speed coincides more or less roughly with the engine's redline in
top gear. There are many exceptions to this rule (specifically
tourers with tall top gears optimized for low-rpm cruisng) but for
most bikes they're not too far off.

> Suppose we reduce the max load by 50 percent,
> how will this reduction affect acceleration performance?

It will help.

> Suppose we reduce the max load by another 50 percent,
> for a total reduction of 75 percent, how will this affect
> acceleration performance?

Any weight reduction helps improve acceleration-- that was never in
dispute.

> Is a 50 to 75 percent reduction in load sufficient
> to offset, if not negate, the loss of acceleration
> performance of the 15 percent reduction in the rear
> sprocket?

Maybe. Impossible to say without having a specific case to
consider.

Weight reduction has nothing to do with top speed, assuming
you have an essentially unlimited distance, otherwise you
are talking about an acceleration contest, as in drag racing.
Get that concept firmly entrenched in your mind. You keep
confusing acceleration with top speed.

I really don't know why I bother responding. At the risk of
being accused of resorting to an ad hominem attack, you appear
to be incapable of grasping the most basic concepts relating
to power, acceleration and top speed.

--
'01 SV650S '99 EX250-F13 '98 ZG1000-A13
OMF #7
The Older Gentleman
2007-03-17 19:30:54 UTC
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Mark Olson <***@tiny.invalid> wrote:

> you appear
> to be incapable of grasping the most basic concepts relating
> to power, acceleration and top speed.

Indeed. It's a long time since we had such an awesome demonstration of
total ignorance and stupidity here.


--
BMW K1100LT 750SS CB400F CD250 Z650
GAGARPHOF#30 GHPOTHUF#1 BOTAFOT#60 ANORAK#06 YTC#3
BOF#30 WUSS#5 The bells, the bells.....
Zaphod Beeblebrock
2007-03-18 16:40:52 UTC
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On Sat, 17 Mar 2007 14:15:43 -0500, Mark Olson wrote:

> Zaphod Beeblebrock wrote:


>> Is a 50 to 75 percent reduction in load sufficient to offset, if not
>> negate, the loss of acceleration performance of the 15 percent reduction
>> in the rear sprocket?
>
> Maybe. Impossible to say without having a specific case to consider.

We do have a specific case. Since I don't have the specific data as to the
gearing, etc. I left it general, allowing one to make reasonable
assumptions as regards the ratios and loads to arrive at a general idea.

> Weight reduction has nothing to do with top speed, assuming you have an
> essentially unlimited distance, otherwise you are talking about an
> acceleration contest, as in drag racing. Get that concept firmly
> entrenched in your mind. You keep confusing acceleration with top speed.
>
> I really don't know why I bother responding. At the risk of being accused
> of resorting to an ad hominem attack, you appear to be incapable of
> grasping the most basic concepts relating to power, acceleration and top
> speed.

I'll not accuse you of an ad hominem attack. If I read this right, you are
saying that you believe *I* am saying:

Less weight = higher top speed (period).



That is NOT my intention. What I am saying is that:

1) Taller gearing = higher top speed

2) Taller gearing imposes a performance hit on low-end acceleration

3) Less weight means I can AFFORD to sacrifice the low-end
performance in exchange for the top-end gain.

That's it.

--
Falcon's Rest
Zymurgical Alchemy
First Inter-Galactic Guild House Of
The Brotherhood Of St. Cathode Of Anode
The Older Gentleman
2007-03-18 16:44:31 UTC
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Zaphod Beeblebrock <***@TheUniverseTheRestaurant.com> wrote:



>
> I'll not accuse you of an ad hominem attack. If I read this right, you are
> saying that you believe *I* am saying:
>
> Less weight = higher top speed (period).
>
>
>
> That is NOT my intention. What I am saying is that:
>
> 1) Taller gearing = higher top speed
>
> 2) Taller gearing imposes a performance hit on low-end acceleration
>
> 3) Less weight means I can AFFORD to sacrifice the low-end
> performance in exchange for the top-end gain.
>

<Shakes head in amazement>

Fuck, you're stupid.


--
BMW K1100LT 750SS CB400F CD250 Z650
GAGARPHOF#30 GHPOTHUF#1 BOTAFOT#60 ANORAK#06 YTC#3
BOF#30 WUSS#5 The bells, the bells.....
Mark Clements
2007-03-18 16:45:00 UTC
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Zaphod Beeblebrock wrote:
> On Sat, 17 Mar 2007 14:15:43 -0500, Mark Olson wrote:
>
>> Zaphod Beeblebrock wrote:
>
>
>>> Is a 50 to 75 percent reduction in load sufficient to offset, if not
>>> negate, the loss of acceleration performance of the 15 percent reduction
>>> in the rear sprocket?
>> Maybe. Impossible to say without having a specific case to consider.
>
> We do have a specific case. Since I don't have the specific data as to the
> gearing, etc. I left it general, allowing one to make reasonable
> assumptions as regards the ratios and loads to arrive at a general idea.
>
>> Weight reduction has nothing to do with top speed, assuming you have an
>> essentially unlimited distance, otherwise you are talking about an
>> acceleration contest, as in drag racing. Get that concept firmly
>> entrenched in your mind. You keep confusing acceleration with top speed.
>>
>> I really don't know why I bother responding. At the risk of being accused
>> of resorting to an ad hominem attack, you appear to be incapable of
>> grasping the most basic concepts relating to power, acceleration and top
>> speed.
>
> I'll not accuse you of an ad hominem attack. If I read this right, you are
> saying that you believe *I* am saying:
>
> Less weight = higher top speed (period).
>
>
>
> That is NOT my intention. What I am saying is that:
>
> 1) Taller gearing = higher top speed

Sure: if unlimited power is available. The internal combustion engine
does not supply unlimited power.

> 2) Taller gearing imposes a performance hit on low-end acceleration
>
> 3) Less weight means I can AFFORD to sacrifice the low-end
> performance in exchange for the top-end gain.
>
> That's it.
>
Mark Olson
2007-03-18 16:55:11 UTC
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Mark Clements wrote:
> Zaphod Beeblebrock wrote:

>> 1) Taller gearing = higher top speed
>
> Sure: if unlimited power is available. The internal combustion engine
> does not supply unlimited power.

ZB has been told this over and over, by different people, in
multiple ways, and apparently *still* hasn't twigged onto it.

--
'01 SV650S '99 EX250-F13 '98 ZG1000-A13
OMF #7
The Older Gentleman
2007-03-18 16:59:21 UTC
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Mark Olson <***@tiny.invalid> wrote:

> Mark Clements wrote:
> > Zaphod Beeblebrock wrote:
>
> >> 1) Taller gearing = higher top speed
> >
> > Sure: if unlimited power is available. The internal combustion engine
> > does not supply unlimited power.
>
> ZB has been told this over and over, by different people, in
> multiple ways, and apparently *still* hasn't twigged onto it.

I'm beginning to wonder if we aren't being subtly trolled here. *Nobody*
can be that ignorant of basic physics and mechanics, can they?


--
BMW K1100LT 750SS CB400F CD250 Z650
GAGARPHOF#30 GHPOTHUF#1 BOTAFOT#60 ANORAK#06 YTC#3
BOF#30 WUSS#5 The bells, the bells.....
John Johnson
2007-03-18 17:53:43 UTC
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In article
<1hv6kh8.1yzavix14iduyfN%***@dsl.pipex.com>,
***@dsl.pipex.com (The Older Gentleman) wrote:

> Mark Olson <***@tiny.invalid> wrote:
>
> > Mark Clements wrote:
> > > Zaphod Beeblebrock wrote:
> >
> > >> 1) Taller gearing = higher top speed
> > >
> > > Sure: if unlimited power is available. The internal combustion engine
> > > does not supply unlimited power.
> >
> > ZB has been told this over and over, by different people, in
> > multiple ways, and apparently *still* hasn't twigged onto it.
>
> I'm beginning to wonder if we aren't being subtly trolled here. *Nobody*
> can be that ignorant of basic physics and mechanics, can they?

Yes, yes they can. It's been said that most people are more-or-less
Aristotelians in their view of the world, and Zaphod certainly gives a
number of statements that would agree nicely with Aristotelian physics.
I've run into many other who believe similarly. The problem, as you
point out so often WRT B-12, isn't the ignorance so much as the
presentation of ignorance as knowledge.

Learning enough mechanics and aerodynamics to get a solid understanding
of the matter isn't difficult (from where I sit, but wait), but it's not
trivial either. I still get physics stuff wrong regularly, and I'm far
better at it than most my friends who aren't either physicists or
engineers.

> That is NOT my intention. What I am saying is that:
>
> 1) Taller gearing = higher top speed
>
Think of this question: where is the power that increases the top speed
coming from? Surely it takes more power to push a given machine faster?
Changing gearing doesn't change the hp output of the machine, so how
does it increase the top speed rather than only the time to reach top
speed?

Remember that we're not talking about distance-limited speed here, but
the speed achievable if we've got an unlimited straight distance to run.

--
Later,
John

***@indianahoosiers.edu

'indiana' is a 'nolnn' and 'hoosier' is a 'solkk'. Indiana doesn't solkk.
mk10
2007-03-18 18:19:16 UTC
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I must admit that this thread has indeed been amusing the past few
days...however all good things must come to an end...



ZB, just admit:

- your speedo probably read high about 10% (not uncommon for Japanese bikes
from that era and also of today)

- you were young and probably exaggerated a bit to the police/friends when
talking about your crash

- since it happened such a long time ago, your memory recollection wasn't
entirely accurate



You thought you were going 120mph, however in light of the facts presented,
you now realize that speed was impossible to attain and you were probably
only going about 85-90mph (which is still more than respectable and
ridiculously fast for that squirrelly, crappy handling bike).



Save face, admit your mistake, apologize, and let's move on.




"The Older Gentleman" <***@dsl.pipex.com> wrote in
message
news:1hv6kh8.1yzavix14iduyfN%***@dsl.pipex.com...
> Mark Olson <***@tiny.invalid> wrote:
>
>> Mark Clements wrote:
>> > Zaphod Beeblebrock wrote:
>>
>> >> 1) Taller gearing = higher top speed
>> >
>> > Sure: if unlimited power is available. The internal combustion engine
>> > does not supply unlimited power.
>>
>> ZB has been told this over and over, by different people, in
>> multiple ways, and apparently *still* hasn't twigged onto it.
>
> I'm beginning to wonder if we aren't being subtly trolled here. *Nobody*
> can be that ignorant of basic physics and mechanics, can they?
>
>
> --
> BMW K1100LT 750SS CB400F CD250 Z650
> GAGARPHOF#30 GHPOTHUF#1 BOTAFOT#60 ANORAK#06 YTC#3
> BOF#30 WUSS#5 The bells, the bells.....
Ted Mittelstaedt
2007-03-19 06:30:07 UTC
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"Zaphod Beeblebrock" <***@TheUniverseTheRestaurant.com> wrote in message
news:***@TheUniverseTheRestaurant.com...
>
> I'll not accuse you of an ad hominem attack. If I read this right, you are
> saying that you believe *I* am saying:
>
> Less weight = higher top speed (period).
>
>
>
> That is NOT my intention. What I am saying is that:
>
> 1) Taller gearing = higher top speed
>

Only if the existing gearing on the machine causes the engine RPM to
go higher than it's powerband at top speed.

What is happening on the stock machines is that due to gearing the
engine power starts falling off at higher and higher speeds, so an
equilibrium is reached between the wind drag and the engine output
power such that the machine will not go faster than a certain speed.

If you make the gearing taller you MAY make the engine RPM go
back into it's powerband and so at higher speeds have more available
horsepower and so a new equilibrium is reached that is at a higher speed.
Of course you may lose accelleration at lower end if you do not adjust
your shift points.

> 2) Taller gearing imposes a performance hit on low-end acceleration
>

maybe maybe not it all depends on how the factory did it.

> 3) Less weight means I can AFFORD to sacrifice the low-end
> performance in exchange for the top-end gain.
>

Ah, not exactly.

Ted
The Older Gentleman
2007-03-17 19:30:54 UTC
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Zaphod Beeblebrock <***@TheUniverseTheRestaurant.com> wrote:

> why don't you explain to my ignorant self just
> exactly what happens if you change the gear ratio by reducing the size of
> the rear sprocket say, from 48 teeth to 42 teeth, a reduction of roughly a
> bit under 15 percent?
>
> Will it hurt acceleration performance?

Substantially.

>
> Will it increase top speed?

No. It will almost certainly reduce it in top gear, meaning top speed
will be attainable in a lower gear. Unless, of course, the bike was
massively undergeared to begin with.

>
> Suppose we reduce the max load by 50 percent,
> how will this reduction affect acceleration performance?

If, by load, you mean weight, it will improve it.
>
> Suppose we reduce the max load by another 50 percent,
> for a total reduction of 75 percent, how will this affect
> acceleration performance?

See above

>
> Is a 50 to 75 percent reduction in load sufficient
> to offset, if not negate, the loss of acceleration
> performance of the 15 percent reduction in the rear
> sprocket?

We're not talking acceleration - we're talking top speed, in this
thread. They are two different things. You said gearing up a CB360 will
make it hit 120mph. Everyone else says you're talking shit, and you are.

You are truly, truly ignorant. And stupid.


--
BMW K1100LT 750SS CB400F CD250 Z650
GAGARPHOF#30 GHPOTHUF#1 BOTAFOT#60 ANORAK#06 YTC#3
BOF#30 WUSS#5 The bells, the bells.....
Mark Olson
2007-03-15 19:11:19 UTC
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Zaphod Beeblebrock wrote:
> On Wed, 14 Mar 2007 10:19:43 -0700, chateau.murray wrote:
>
>
>>On 14 Mar, 17:21, Mark Olson <***@tiny.invalid> wrote:
>>
>>>***@btinternet.com wrote:
>>>
>>>>On 14 Mar, 15:24, Zaphod Beeblebrock
>>>><***@TheUniverseTheRestaurant.com> wrote:
>>>
>>>>>I've owned a couple of the early '70s CL360s and, after a bit of
>>>>>tinkering[1], could get them up past 120mph. Carrying a passenger was
>>>>>never a problem either...but, I only weigh about 140lbs and it doesn't
>>>>>take too many horses to pull my bean-pole bod down the road.
>>>>>(Unfortunately, even at that light weight they don't fly very well,
>>>>>even at 120+mph, after leaving said road on a banked curve. They
>>>>>aren't much good for riding on afterward, either.)
>>>
>>>>>[1]The tinkering was mostly just fine-tuning the motor and changing
>>>>>the rear sprocket and the chain.
>>>
>>>>Blimey. To get a 360 to that sort of speed would need booster rockets,
>>>>I'd have thought.
>>>
>>>This sounds suspiciously like the guy who claimed he got his stock
>>>CB900C to 160 mph just by carefully tweaking the carbs. When a couple
>>>of people told him he was dreaming he got a bit upset.
>>>
>>>http://groups.google.com/group/rec.autos.makers.ford.explorer/msg/c5f...
>>>
>>>
>>
>>Heh. Yes, exactly the same. My old CB360 would do about 95+ indicated,
>>flat out. To get one to do a genuine 120mph would require serious deep
>>surgery. And a tuned speedometer as well. The old SOHC 750s would just
>>about hit 120 on a good day, but most of the time 110-115 was your lot. No
>>way would a 360 twin get anywhere near that speed.
>
>
>
> If you will think about it rationally for a moment gentlemen, before
> simply *assuming* that I am exaggerating, consider what I said about
> changing out the rear sprocket.

I don't care what you did to the sprockets, without a dustbin
fairing on that 360, or lots of very expensive engine work,
you don't have an icecube's chance in hell of getting it up
to 120 mph. There are certain basic facts that you can't weasel
out of-- and there's always somebody on Usenet who knows far,
far more about a subject than you or I do...

> Picture a multi-speed bicycle with different sized sprockets on the front
> and rear. Consider your legs to be the two cylinders. Pumping your legs at
> a given rate (RPM) will propel you at a given speed. If you shift the rear
> derailleur to a _smaller_ sprocket, then pumping your legs at the same
> rate as before will propel you at a *faster* speed.
>
> Granted, the smaller rear sprocket will change the torque(?) ratio, but at
> my relatively light body weight the sacrifice is an acceptable trade-off
> for the higher top speed.
>
> There is nothing magical or delusional about this:
>
> Smaller rear sprocket = higher top speed.

No. The faster you go, the more power it takes to get there.
If your engine doesn't make the raw power it takes to force
you and your bike through the air, no amount of messing with
gearing is going to make it faster. I learned this way back
in 6th grade when I hit on the idea of putting a large sprocket
on the centrifugal clutch of my doodle bug and a tiny sprocket
on the back wheel. Doing the simple math told me I could achieve
hundreds of miles per hour with a 5 hp Briggs and Stratton engine.
Thankfully the laws of physics have remained intact despite my
high hopes and it isn't going to work any better for you than it
did for me in my long-ago thought experiment.

> Now, if you would like to be helpful, I wouldn't mind a little advice on
> performing a similar modification on my current machine. It is a '96
> Yamaha Virago 1100 Special which produces *far* more horsepower than is
> necessary to pull my skinny ass down the road.

How much you weigh has *nothing* to do with top speed on a level
surface. It greatly affects acceleration, but air resistance
dominates your eventual top speed.

> This is the first bike I've owned with a shaft-drive. I am constantly
> wishing it had a sixth gear in it. I'm not as much as a speed-freak as I
> was when I was younger, I'd just like to lower the RPM for cruising and
> improve the fuel milage...especially since it seems like the alcohol mix
> I'm getting for fuel now has put a drastic hit on it. I used to be able to
> get 165-170 miles before the low-fuel light would come on, I ran dry the
> other day at 136mi.
>
> I experienced the same phenomenon on a trip to Texas last year. Straight
> regular gas gave me the expected milage, the alcohol mix reduced it,
> requiring more frequent fuel stops.
>
> I have my doubts about the feasibility of changing the gearing where the
> shaft meets the rear axle, which means that I'd probably have to change
> the transmission gears. Is either one of these ideas feasible, without
> going to extreme effort or expense?

You might be able to swap in the rear end from a different bike. Other
than that, there's no easy or cheap way to change the final drive ratio
on most shaft drive bikes.

--
'01 SV650S '99 EX250-F13 '98 ZG1000-A13
OMF #7
Zaphod Beeblebrock
2007-03-15 21:27:26 UTC
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Raw Message
On Thu, 15 Mar 2007 14:11:19 -0500, Mark Olson wrote:

> Zaphod Beeblebrock wrote:
>> On Wed, 14 Mar 2007 10:19:43 -0700, chateau.murray wrote:

>> If you will think about it rationally for a moment gentlemen, before
>> simply *assuming* that I am exaggerating, consider what I said about
>> changing out the rear sprocket.
>
> I don't care what you did to the sprockets, without a dustbin fairing on
> that 360, or lots of very expensive engine work, you don't have an
> icecube's chance in hell of getting it up to 120 mph. There are certain
> basic facts that you can't weasel out of-- and there's always somebody on
> Usenet who knows far, far more about a subject than you or I do...
>
>> Picture a multi-speed bicycle with different sized sprockets on the
>> front and rear. Consider your legs to be the two cylinders. Pumping your
>> legs at a given rate (RPM) will propel you at a given speed. If you
>> shift the rear derailleur to a _smaller_ sprocket, then pumping your
>> legs at the same rate as before will propel you at a *faster* speed.
>>
>> Granted, the smaller rear sprocket will change the torque(?) ratio, but
>> at my relatively light body weight the sacrifice is an acceptable
>> trade-off for the higher top speed.
>>
>> There is nothing magical or delusional about this:
>>
>> Smaller rear sprocket = higher top speed.
>
> No. The faster you go, the more power it takes to get there. If your
> engine doesn't make the raw power it takes to force you and your bike
> through the air, no amount of messing with gearing is going to make it
> faster. I learned this way back in 6th grade when I hit on the idea of
> putting a large sprocket on the centrifugal clutch of my doodle bug and a
> tiny sprocket on the back wheel. Doing the simple math told me I could
> achieve hundreds of miles per hour with a 5 hp Briggs and Stratton engine.
> Thankfully the laws of physics have remained intact despite my high hopes
> and it isn't going to work any better for you than it did for me in my
> long-ago thought experiment.
>
>
> How much you weigh has *nothing* to do with top speed on a level surface.
> It greatly affects acceleration, but air resistance dominates your
> eventual top speed.


Actually, it does. With a lighter load and less torque required for
acceleration, more of the engine's horsepower can be used for overcoming
wind resistance, etc. The less available horsepower you have, the bigger
the difference.

Take your 5 horse B&S motor, take two of them actually, and build two
identical go-karts. Put me on one and a 300lb guy on the other and we do
10 laps around a quarter mile track. Who do you think is going to win the
race?

Granted, in this case wind resistance isn't much of an issue because the
top speed doesn't get high enough for it to matter much. But, put 12"
tires on those carts instead of 10" tires (we'll change tire size since it
accomplishes basically the same thing as changing the gear ratio) and what
happens?

If we do another 10 laps, I'm going to win by an even bigger
margin...assuming that my opponent can get moving at all.

Now take me and that same 300lb guy and put us both on identical stock
CL360s...I'm guessing that they might put out about, oh, 24 horses? We run
a straight 10 mile stretch of level highway- I'm faster off the line
because I have less load to accelerate, it requires less energy to
maintain my momentum AND, because I'm skinny and he's fat, *he* needs more
energy to overcome wind resistance than I do, which becomes an increasing
factor as speeds increase.

Now take those same machines and change out the rear sprockets for
sprockets with six fewer teeth. What's going to happen? Acceleration
becomes a greater factor, but more for him than for me. With a lighter
load and less wind resistance I'm going to beat him by an even bigger
margin. The change in gear ratio doesn't affect me as much as it affects
him because of his greater weight and larger size.

Give him back his larger sprocket and set us off again- I'll bet I'm still
faster off the line AND, because I have the taller gearing and less wind
resistance I'm going to go a LOT faster than he is.


On the other hand, if you were to put us both on bikes powered by 454 Olds
Rocket motors, my size and weight wouldn't mean diddly because of all the
excess horsepower available. With limited horsepower size and weight can
matter more.



>> This is the first bike I've owned with a shaft-drive. I am constantly
>> wishing it had a sixth gear in it. I'm not as much as a speed-freak as I
>> was when I was younger, I'd just like to lower the RPM for cruising and
>> improve the fuel milage...especially since it seems like the alcohol mix
>> I'm getting for fuel now has put a drastic hit on it. I used to be able
>> to get 165-170 miles before the low-fuel light would come on, I ran dry
>> the other day at 136mi.
>>
>> I experienced the same phenomenon on a trip to Texas last year. Straight
>> regular gas gave me the expected milage, the alcohol mix reduced it,
>> requiring more frequent fuel stops.
>>
>> I have my doubts about the feasibility of changing the gearing where the
>> shaft meets the rear axle, which means that I'd probably have to change
>> the transmission gears. Is either one of these ideas feasible, without
>> going to extreme effort or expense?
>
> You might be able to swap in the rear end from a different bike. Other
> than that, there's no easy or cheap way to change the final drive ratio on
> most shaft drive bikes.


Thanks, I had a feeling that might be the answer I was going to get.


--
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Zymurgical Alchemy
First Inter-Galactic Guild House Of
The Brotherhood Of St. Cathode Of Anode
Mark Olson
2007-03-15 21:47:05 UTC
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Zaphod Beeblebrock wrote:
> On Thu, 15 Mar 2007 14:11:19 -0500, Mark Olson wrote:

>> How much you weigh has *nothing* to do with top speed on a level surface.
>> It greatly affects acceleration, but air resistance dominates your
>> eventual top speed.
>
>
> Actually, it does. With a lighter load and less torque required for
> acceleration, more of the engine's horsepower can be used for overcoming
> wind resistance, etc. The less available horsepower you have, the bigger
> the difference.

NO IT DOESN'T. Take your CL360 out to the Bonneville Salt flats or
some other place where you've got miles and miles of flat in front
of you-- that's what I'm talking about WRT top speed. Once you reach
top speed, none of your engine's power is being used to accelerate
the mass of the bike + you, that's the definition of top speed, the
speed at which you stop accelerating.

There is of course a small penalty to pay in increased rolling resistance
because a heavier rider compresses the tires a bit more, the bearings
have an infinitesimally greater amount of friction, etc. but in the real
world, the only reason a lighter rider will acheive a top speed is because
he is physically skinnier, and presents less cross section to the wind,
than a more portly rider, not because he weighs less.

> Take your 5 horse B&S motor, take two of them actually, and build two
> identical go-karts. Put me on one and a 300lb guy on the other and we do
> 10 laps around a quarter mile track. Who do you think is going to win the
> race?

I don't care- you've moved the goalposts. Earlier you were talking
about top speed. Sure, the kart with the lighter driver will be faster,
assuming it's not a technical track and the fat guy is a better driver.

Look, I know you mean well, but you're wrong about a stock CL360 hitting
120 mph on the flat, without a fairing or a tailwind. Never happened,
never will. Not even riding it Rollie Free style, I'll wager.

--
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OMF #7
Ian Singer
2007-03-15 23:12:00 UTC
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Mark Olson wrote:

>
> Look, I know you mean well, but you're wrong about a stock CL360 hitting
> 120 mph on the flat, without a fairing or a tailwind. Never happened,
> never will. Not even riding it Rollie Free style, I'll wager.
>
OK so based on what you are saying how fast should a CB160 be able to go
with a full windshield and no fairing? Driver wearing 3/4 helmet with a
curved molded bubble and not flat on the tank.

Ian Singer

--


=========================================================================
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hosted on http://www.1and1.com/?k_id=10623894
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The Older Gentleman
2007-03-16 07:20:57 UTC
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Ian Singer <***@sympatico.ca> wrote:

> OK so based on what you are saying how fast should a CB160 be able to go
> with a full windshield and no fairing? Driver wearing 3/4 helmet with a
> curved molded bubble and not flat on the tank.

In stock trim? Maybe 75mph. I've had a few dozen CD and CB175s, which
aren't so different in terms of size, weight and power output.

Screens and fairings make precious little difference at that sort of
speed, except to rider (dis)comfort.


--
BMW K1100LT 750SS CB400F CD250 Z650
GAGARPHOF#30 GHPOTHUF#1 BOTAFOT#60 ANORAK#06 YTC#3
BOF#30 WUSS#5 The bells, the bells.....
Zaphod Beeblebrock
2007-03-16 00:01:47 UTC
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On Thu, 15 Mar 2007 16:47:05 -0500, Mark Olson wrote:


> Look, I know you mean well, but you're wrong about a stock CL360 hitting
> 120 mph on the flat, without a fairing or a tailwind. Never happened,
> never will. Not even riding it Rollie Free style, I'll wager.

OK, one more time. If you go back to my original post, you will see that I
DID NOT say it was a "stock" CL360.

I changed out the rear sprocket for a smaller one, sacrificing some
acceleration/torque(?) on the low end in exchange for a higher top speed.
Changing the rear sprocket changes the gear ratio.

My reference to my weight was primarily an indication that I could afford
that sacrifice.

Does it make more sense now?


--
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Zymurgical Alchemy
First Inter-Galactic Guild House Of
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Mark Olson
2007-03-16 02:47:30 UTC
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Zaphod Beeblebrock wrote:
> On Thu, 15 Mar 2007 16:47:05 -0500, Mark Olson wrote:
>
>
>> Look, I know you mean well, but you're wrong about a stock CL360 hitting
>> 120 mph on the flat, without a fairing or a tailwind. Never happened,
>> never will. Not even riding it Rollie Free style, I'll wager.
>
> OK, one more time. If you go back to my original post, you will see that I
> DID NOT say it was a "stock" CL360.
>
> I changed out the rear sprocket for a smaller one, sacrificing some
> acceleration/torque(?) on the low end in exchange for a higher top speed.
> Changing the rear sprocket changes the gear ratio.
>
> My reference to my weight was primarily an indication that I could afford
> that sacrifice.
>
> Does it make more sense now?

To you, perhaps.

Changing the size of the sprockets doesn't affect the engine's maximum
power output at all. Power output is the limiting factor keeping a
CL360 from achieving 120 mph, not gearing. There just isn't enough
energy per unit time being emitted by that engine to overcome the
aerodynamic drag.

--
'01 SV650S '99 EX250-F13 '98 ZG1000-A13
OMF #7
Zaphod Beeblebrock
2007-03-16 13:40:52 UTC
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On Thu, 15 Mar 2007 21:47:30 -0500, Mark Olson wrote:

> Zaphod Beeblebrock wrote:
>> On Thu, 15 Mar 2007 16:47:05 -0500, Mark Olson wrote:
>>
>>
>>> Look, I know you mean well, but you're wrong about a stock CL360
>>> hitting 120 mph on the flat, without a fairing or a tailwind. Never
>>> happened, never will. Not even riding it Rollie Free style, I'll
>>> wager.
>>
>> OK, one more time. If you go back to my original post, you will see that
>> I DID NOT say it was a "stock" CL360.
>>
>> I changed out the rear sprocket for a smaller one, sacrificing some
>> acceleration/torque(?) on the low end in exchange for a higher top
>> speed. Changing the rear sprocket changes the gear ratio.
>>
>> My reference to my weight was primarily an indication that I could
>> afford that sacrifice.
>>
>> Does it make more sense now?
>
> To you, perhaps.
>
> Changing the size of the sprockets doesn't affect the engine's maximum
> power output at all. Power output is the limiting factor keeping a CL360
> from achieving 120 mph, not gearing. There just isn't enough energy per
> unit time being emitted by that engine to overcome the aerodynamic drag.

OK, have it your way. Practical and professional experience rebuilding
motors and racing since age 12 counts for nothing and is negated by your
theoretical calculations. Nobody has ever taken a 350/360cc motor to 120+,
if you say it can't be done, then it can't be done. I bow to the awesome
power of your mind which has the ability to cancel reality.

Why don't you tell that to these guys, that the one with the 350 didn't go
to 189, and the other guy with the 100cc motor didn't go to 140:

http://www.scta-bni.org/Bonneville/records/BNIrecs_bikes.htm

(Thanks to Rick Cortese for the link.)

120mph out of a CL360 is not particularly difficult. 189, on the other
hand, takes a bit more doing.


--
Falcon's Rest
Zymurgical Alchemy
First Inter-Galactic Guild House Of
The Brotherhood Of St. Cathode Of Anode
Mark Olson
2007-03-16 14:19:45 UTC
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Zaphod Beeblebrock wrote:
> On Thu, 15 Mar 2007 21:47:30 -0500, Mark Olson wrote:
>
>
>>Zaphod Beeblebrock wrote:
>>
>>>On Thu, 15 Mar 2007 16:47:05 -0500, Mark Olson wrote:

>>>>Look, I know you mean well, but you're wrong about a stock CL360
>>>>hitting 120 mph on the flat, without a fairing or a tailwind. Never
>>>>happened, never will. Not even riding it Rollie Free style, I'll
>>>>wager.
>>>
>>>OK, one more time. If you go back to my original post, you will see that
>>>I DID NOT say it was a "stock" CL360.
>>>
>>>I changed out the rear sprocket for a smaller one, sacrificing some
>>>acceleration/torque(?) on the low end in exchange for a higher top
>>>speed. Changing the rear sprocket changes the gear ratio.
>>>
>>>My reference to my weight was primarily an indication that I could
>>>afford that sacrifice.
>>>
>>>Does it make more sense now?
>>
>>To you, perhaps.
>>
>>Changing the size of the sprockets doesn't affect the engine's maximum
>>power output at all. Power output is the limiting factor keeping a CL360
>>from achieving 120 mph, not gearing. There just isn't enough energy per
>>unit time being emitted by that engine to overcome the aerodynamic drag.

> OK, have it your way. Practical and professional experience rebuilding
> motors and racing since age 12 counts for nothing and is negated by your
> theoretical calculations. Nobody has ever taken a 350/360cc motor to 120+,
> if you say it can't be done, then it can't be done. I bow to the awesome
> power of your mind which has the ability to cancel reality.

Ah, the old 'appeal to authority' argument. Never fails, when you can't
weasel out of some bullshit you tried to pull, the old, 'I've been doing
this for years, why do you doubt me' wheeze. I've got news for you, there
are people on this newsgroup that actually do know what they are talking
about and you are making yourself

Nope. I never said a 350/360cc engine couldn't get to 120mph. What I did
say, was your stock CL360 didn't do it, can't do it, because it was a
stock bike without any sort of engine mods or fairing on it. Changing
the sprockets doesn't make your bike 'custom', if you want to cling to
that 'mod' as somehow elevating your CL360 to non-stock, fine. But it
doesn't change how much power the engine puts out, and if the power isn't
there, it won't get to 120 mph, no matter how much you want it to.

> Why don't you tell that to these guys, that the one with the 350 didn't go
> to 189, and the other guy with the 100cc motor didn't go to 140:
>
> http://www.scta-bni.org/Bonneville/records/BNIrecs_bikes.htm

Do you know what those various class designations mean? Somehow I doubt
a stock 100cc bike is going to hit 140, and I will bet my life that the
189 mph 350cc bike was a streamliner. But keep on ignoring the fact that
your CL360 isn't a streamliner, as TOG says, you keep on showing how
little you know about bikes and simple physics.

> (Thanks to Rick Cortese for the link.)
>
> 120mph out of a CL360 is not particularly difficult. 189, on the other
> hand, takes a bit more doing.

Go on. Get 120 mph out of your CL360. It *can* be done. But it won't
be done simply by changing the sprockets and giving the bike a tune up.

--
'01 SV650S '99 EX250-F13 '98 ZG1000-A13
OMF #7
chateau.murray@btinternet.com,
2007-03-16 14:22:32 UTC
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On 16 Mar, 14:40, Zaphod Beeblebrock
<***@TheUniverseTheRestaurant.com> wrote:
> On Thu, 15 Mar 2007 21:47:30 -0500, Mark Olson wrote:
> > Zaphod Beeblebrock wrote:


> OK, have it your way. Practical and professional experience rebuilding
> motors and racing since age 12 counts for nothing and is negated by your
> theoretical calculations.

No, it doesn't. Try riding a few bikes, and by a few, I mean 'several
hundred'. Dunno about Mark, but I reckon I've owned something like
250-300 bikes in the last 30+ years, and ridden probably another
couple of hundred. This tends to give one a fairly empirical and
accurate view.


>Nobody has ever taken a 350/360cc motor to 120+,
> if you say it can't be done, then it can't be done. I bow to the awesome
> power of your mind which has the ability to cancel reality.

Oh, it can be done. The CB350 is quite keenly sought after by the
classic racing boys here in Europe, and can be tuned to go
surprisingly quickly. What Mark is saying, and what I'm saying, is
that a couple of basic mods will not make one do 120. It just won't.

As a very rough rule of thumb, production road bikes need something
like 28-30bhp in order to reach 100mph. To get to 120, you need about
60bhp. Obviously there are other factors here, like the bike size:
Honda racing 125 two-strokes will hit high speeds on considerably less
than 60bhp, but we're talking road bikes here.

The old 360 twin made a claimed 34bhp, in an era when bikes weren't
routinely dyno tested. Assuming something like 25-28bhp at the rear
wheel gives it a top speed of round about 100 - a good one might do
it, and an average one might not, but let's be generous.

To get 120 out of one, you'd need to raise the rear wheel horsepower
to around 50bhp, given the size/bulk of the old 360. Take the Ducati
750SS in my(other) sig: that has a claimed 64bhp and will do
125-127mph, according to differing road test measurements. Most I have
ever seen on the clock is 125: a racer friend managed 130. I reckon
rear wheel horsepower is about 55-60bhp. So we're talking about a bike
that's twice the capacity, nearly twice the rated horsepower, which
manages a mere 5-10mph faster than you claim for your old shonker.

Sorry, you're living in a dream world, unless you paid for some very,
very expensive surgery. Or had a speedo that was more inaccurate than
usual. Or conceivably, laced a smaller diameter front rim to the hub,
which would cause the speedo to do silly things.

>
> Why don't you tell that to these guys, that the one with the 350 didn't go
> to 189, and the other guy with the 100cc motor didn't go to 140:
>
> http://www.scta-bni.org/Bonneville/records/BNIrecs_bikes.htm
>
> (Thanks to Rick Cortese for the link.)

These are pukka race/record breaking bikes, you utter imbecile, not
played-with soggy old Honda road twins.
>
> 120mph out of a CL360 is not particularly difficult.

Yes, it is.

Right, your basic ignorance of physics and other things have been
adequately pointed out. Other matters like faulty insturments have
been flagged up. If you're not prepared to admit you've made a howling
monkey of yourself, not prepared to admit that your speedo might be
lying as much as your President, and not prepared to admit you might
be in error, what does that leave?

Fancy running for President?
Zaphod Beeblebrock
2007-03-17 21:38:03 UTC
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On Fri, 16 Mar 2007 07:22:32 -0700, chateau.murray wrote:



> Right, your basic ignorance of physics and other things have been
> adequately pointed out. Other matters like faulty insturments have been
> flagged up. If you're not prepared to admit you've made a howling monkey
> of yourself, not prepared to admit that your speedo might be lying as much
> as your President, and not prepared to admit you might be in error, what
> does that leave?

I will concede that the speedo *could* have been off, but not by all that
goddam much. Certainly not enough to justify the trash-talking that was
dished out right out of the gate. Seems to me that some people are just a
little too eager to flame.

The front wheel was the factory wheel. I didn't check the calibration of
the speedo, in those days I didn't care much about speed limits.

--
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The Older Gentleman
2007-03-17 22:06:07 UTC
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Zaphod Beeblebrock <***@TheUniverseTheRestaurant.com> wrote:

> I will concede that the speedo *could* have been off, but not by all that
> goddam much.

Oh yes, it could.

> didn't check the calibration of the speedo

No shit.


--
BMW K1100LT 750SS CB400F CD250 Z650
GAGARPHOF#30 GHPOTHUF#1 BOTAFOT#60 ANORAK#06 YTC#3
BOF#30 WUSS#5 The bells, the bells.....
The Older Gentleman
2007-03-16 07:20:57 UTC
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Zaphod Beeblebrock <***@TheUniverseTheRestaurant.com> wrote:

> OK, one more time. If you go back to my original post, you will see that I
> DID NOT say it was a "stock" CL360.
>
> I changed out the rear sprocket for a smaller one, sacrificing some
> acceleration/torque(?) on the low end in exchange for a higher top speed.
> Changing the rear sprocket changes the gear ratio.
>
> My reference to my weight was primarily an indication that I could afford
> that sacrifice.
>
> Does it make more sense now?

<VBG>

No, it doesn't. You're giving us a lot of amusement, though. Please keep
playing.


--
BMW K1100LT 750SS CB400F CD250 Z650
GAGARPHOF#30 GHPOTHUF#1 BOTAFOT#60 ANORAK#06 YTC#3
BOF#30 WUSS#5 The bells, the bells.....
Rick Cortese
2007-03-15 21:16:45 UTC
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Zaphod Beeblebrock wrote:
> On Wed, 14 Mar 2007 10:19:43 -0700, chateau.murray wrote:

<snip>
>>Heh. Yes, exactly the same. My old CB360 would do about 95+ indicated,
>>flat out. To get one to do a genuine 120mph would require serious deep
>>surgery. And a tuned speedometer as well. The old SOHC 750s would just
>>about hit 120 on a good day, but most of the time 110-115 was your lot. No
>>way would a 360 twin get anywhere near that speed.
>
>
>
> If you will think about it rationally for a moment gentlemen, before
> simply *assuming* that I am exaggerating, consider what I said about
> changing out the rear sprocket.

I don't think you are exagerating the speedometer reading, I think you
just had a very optimistic speedometer.

Consider
http://www.scta-bni.org/mcycle_classes.htm
where first comes frame, next comes engine
and
http://www.scta-bni.org/Bonneville/records/BNIrecs_bikes.htm

Shows the 350cc LSR for P(roduction)/P(roduction) to be 128mph I kind of
suspect that may be a 350cc two stroke twin but you get the idea.
For comparison purposes since it probably puts out about eh same hp as a
stock 360 a P(r0duction)/P(roduction)P(ush rod) of 90.75MPH.

Now if you had a stock 360 that could do that, well get it back, have it
tuned up a bit, get a jockey sized rider in a wet suit, and you will be
the LSR holder.
Zaphod Beeblebrock
2007-03-16 12:32:17 UTC
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On Thu, 15 Mar 2007 21:16:45 +0000, Rick Cortese wrote:

> Zaphod Beeblebrock wrote:
>> On Wed, 14 Mar 2007 10:19:43 -0700, chateau.murray wrote:
>
> <snip>
>>>Heh. Yes, exactly the same. My old CB360 would do about 95+ indicated,
>>>flat out. To get one to do a genuine 120mph would require serious deep
>>>surgery. And a tuned speedometer as well. The old SOHC 750s would just
>>>about hit 120 on a good day, but most of the time 110-115 was your lot.
>>>No way would a 360 twin get anywhere near that speed.
>>
>>
>>
>> If you will think about it rationally for a moment gentlemen, before
>> simply *assuming* that I am exaggerating, consider what I said about
>> changing out the rear sprocket.
>
> I don't think you are exagerating the speedometer reading, I think you
> just had a very optimistic speedometer.
>
> Consider
> http://www.scta-bni.org/mcycle_classes.htm where first comes frame, next
> comes engine and
> http://www.scta-bni.org/Bonneville/records/BNIrecs_bikes.htm
>
> Shows the 350cc LSR for P(roduction)/P(roduction) to be 128mph I kind of
> suspect that may be a 350cc two stroke twin but you get the idea. For
> comparison purposes since it probably puts out about eh same hp as a stock
> 360 a P(r0duction)/P(roduction)P(ush rod) of 90.75MPH.
>
> Now if you had a stock 360 that could do that, well get it back, have it
> tuned up a bit, get a jockey sized rider in a wet suit, and you will be
> the LSR holder.

Nice. I see where one guy got 140+ out of a 100cc motor, and the highest
in the 350cc class of just over 189. I ran a "go cart" race track for a
while, we used 100cc McCulloch racing motors, with 12" tires we could
squeeze out a top speed of about 107...but those motors were finicky and
had to be torn down and rebuilt just about every day.

I bought my CL used and I don't know if it had been bored out previously,
or any other mods of that nature. I just tuned it and changed out the rear
sprocket and the chain. Unfortunately, I crashed that one and the frame
wasn't salvageable. (The Docs didn't think *I* was salvageable either, and
told me I'd never walk again, but I fooled them.)

--
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Zymurgical Alchemy
First Inter-Galactic Guild House Of
The Brotherhood Of St. Cathode Of Anode
Rick Cortese
2007-03-16 17:40:48 UTC
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Zaphod Beeblebrock wrote:
> On Thu, 15 Mar 2007 21:16:45 +0000, Rick Cortese wrote:
>
>
>>Zaphod Beeblebrock wrote:
>>
>>>On Wed, 14 Mar 2007 10:19:43 -0700, chateau.murray wrote:
>>
>><snip>
>>
>>>>Heh. Yes, exactly the same. My old CB360 would do about 95+ indicated,
>>>>flat out. To get one to do a genuine 120mph would require serious deep
>>>>surgery. And a tuned speedometer as well. The old SOHC 750s would just
>>>>about hit 120 on a good day, but most of the time 110-115 was your lot.
>>>>No way would a 360 twin get anywhere near that speed.
>>>
>>>
>>>
>>>If you will think about it rationally for a moment gentlemen, before
>>>simply *assuming* that I am exaggerating, consider what I said about
>>>changing out the rear sprocket.
>>
>>I don't think you are exagerating the speedometer reading, I think you
>>just had a very optimistic speedometer.
>>
>>Consider
>>http://www.scta-bni.org/mcycle_classes.htm where first comes frame, next
>>comes engine and
>>http://www.scta-bni.org/Bonneville/records/BNIrecs_bikes.htm
>>
>>Shows the 350cc LSR for P(roduction)/P(roduction) to be 128mph I kind of
>>suspect that may be a 350cc two stroke twin but you get the idea. For
>>comparison purposes since it probably puts out about eh same hp as a stock
>>360 a P(r0duction)/P(roduction)P(ush rod) of 90.75MPH.
>>
>>Now if you had a stock 360 that could do that, well get it back, have it
>>tuned up a bit, get a jockey sized rider in a wet suit, and you will be
>>the LSR holder.
>
>
> Nice. I see where one guy got 140+ out of a 100cc motor, and the highest
> in the 350cc class of just over 189. I ran a "go cart" race track for a
> while, we used 100cc McCulloch racing motors, with 12" tires we could
> squeeze out a top speed of about 107...but those motors were finicky and
> had to be torn down and rebuilt just about every day.

I seem to recall a girl on 175 2smoke getting up to ~154. Her father
built the bike and she looked like she weighed maybe a buck 10. But to
get to that speed it was about as far away from stock as you could get
w/o going to a full streamliner/belly tank. The bike had full fairing
and she was in a speed suit with aerodynamic helmet.

I mention that 175 as a somewhat known quantity. Probably puts out about
the same HP as a really highly tuned 350ish OHC 4 stroke. The point is
it takes engine modifications, streamlining, and a pint sized rider to
get to that speed.

The problem I have with a stock bike going that fast vs. what I think
happened<you had a very optimistic speedo> isn't just the HP so much as
the drag at that speed. There's a guy who did several articles for IIRC
Motorcycle Shopper which you may want to look at for just exactly how
much modification was required. He has before and after picts of the
heads and the stock Hondas were pretty restricted. Yeap, you could have
had a hot one where the previous owner hogged out the head, replaced cam
and valve springs, et cetera.

Why I feel this way without personally seeing you ride that bike is I've
been to 110 mph and everything gets light and squirrelly. Frightening
would be more like it. At 120 you are pretty much at what may be
terminal velocity if you were dropped out of a plane. IOW: 1g of air
resistance. The coefficient of friction of a tire of that era was
probably around .75g. This is a common problem<ibid physics> with all
wheel driven vehicles i.e. the other reason why they put wings on
everything from dragsters to formula one cars. It isn't just traction
though, you have a tendency to get light and flutter like a leaf in the
wind at that speed.

Let's use 120mph for terminal velocity => 633,600 ft/hour => 176 ft/sec.

1HP = 550ft lbs/sec.

To keep it simple, bike + rider falling out of that airplane is 550 lbs.
In my case an accurate estimate considering my non aerodynamic lard
ass. Assuming 120mph is terminal velocity, it would take 176hp to push
me and a Honda 360 that fast. Just too much crap like turn signals and
mirrors fluttering in the wind.

Now you can plug any numbers you like in there. Say terminal velocity is
240mph and it would only require 1/4 the HP to go 1/2 as fast, but you
are still talking 44HP. I think 240 is an optimistic terminal velocity
and some people may laugh at the thought of getting 44 rear wheel HP out
of a Honda 360, but heck, it could happen in an alternate universe. The
numbers will work out, I mean you can pretty much expect an 11 hp bike
to go ~60mph.

At one time I was a subscriber to a couple of car magazines. Me being
the anal retentive I was a the time, I graphed hp/lb vs.
acceleration/top speed. It was a smooth curve for everything from a
Bentley to a Volkswagen. Physics works and in the absence of a miracle I
trust it.

Rick
Mark Olson
2007-03-16 19:34:20 UTC
Permalink
Raw Message
Rick Cortese wrote:

> Let's use 120mph for terminal velocity => 633,600 ft/hour => 176 ft/sec.
>
> 1HP = 550ft lbs/sec.
>
> To keep it simple, bike + rider falling out of that airplane is 550 lbs.
> In my case an accurate estimate considering my non aerodynamic lard
> ass. Assuming 120mph is terminal velocity, it would take 176hp to push
> me and a Honda 360 that fast. Just too much crap like turn signals and
> mirrors fluttering in the wind.

Hmmm. How do the 300km/hr or 186 mph bikes (limited by manufacturer's
agreement, some capable of exceeding 200 mph) get going that fast, with
less than 176 hp?

> Now you can plug any numbers you like in there. Say terminal velocity is
> 240mph and it would only require 1/4 the HP to go 1/2 as fast, but you
> are still talking 44HP. I think 240 is an optimistic terminal velocity
> and some people may laugh at the thought of getting 44 rear wheel HP out
> of a Honda 360, but heck, it could happen in an alternate universe. The
> numbers will work out, I mean you can pretty much expect an 11 hp bike
> to go ~60mph.

Doesn't the power required to overcome aerodynamic drag increase as
the cube of the velocity? <cheats, via google> Yep.

This guy (if you squint hard) has a spreadsheet

http://www.msgroup.org/forums/mtt/topic.asp?TOPIC_ID=869

that says for some particular bike & rider, it takes 18.2 hp to go 75, so
to go 120, it takes...

e(3*l(120/75)) * 18.2
74.54719999999999999963

about 75 hp.

With 11 hp, that mythical bike would go about...

75 * (e(l(11/18.2)/3))
63.41154904466300639475

63 mph. You are a genius!

Assuming our favorite bike, the CL360, with an advertised hp of 34 at the
crank, IIRC, has all of that available at the rear wheel, and it's roughly
the same frontal area and coefficient of drag:

75 * (e(l(34/18.2)/3))
92.36989283019552082575

It's going to go about 90 mph tops.

FURTHERMORE...

1/4 the hp to go 1/2 as fast? I think you mean 1/8 the hp to go 1/2 as
fast.

> At one time I was a subscriber to a couple of car magazines. Me being
> the anal retentive I was a the time, I graphed hp/lb vs.
> acceleration/top speed. It was a smooth curve for everything from a
> Bentley to a Volkswagen. Physics works and in the absence of a miracle I
> trust it.

<AOL>

--
'01 SV650S '99 EX250-F13 '98 ZG1000-A13
OMF #7
The Older Gentleman
2007-03-16 19:47:10 UTC
Permalink
Raw Message
Mark Olson <***@tiny.invalid> wrote:

> http://www.msgroup.org/forums/mtt/topic.asp?TOPIC_ID=869
>
> that says for some particular bike & rider, it takes 18.2 hp to go 75, so
> to go 120, it takes...
>
> e(3*l(120/75)) * 18.2
> 74.54719999999999999963
>
> about 75 hp.

I'd query those figures: a decent 14bhp 125 will hit 75, and the
original Honda CB750 did 120+ on a claimed 67bhp.

Pretty close, though.


--
BMW K1100LT 750SS CB400F CD250 Z650
GAGARPHOF#30 GHPOTHUF#1 BOTAFOT#60 ANORAK#06 YTC#3
BOF#30 WUSS#5 The bells, the bells.....
Mark Olson
2007-03-16 20:19:31 UTC
Permalink
Raw Message
The Older Gentleman wrote:
> Mark Olson <***@tiny.invalid> wrote:
>
>
>>http://www.msgroup.org/forums/mtt/topic.asp?TOPIC_ID=869
>>
>>that says for some particular bike & rider, it takes 18.2 hp to go 75, so
>>to go 120, it takes...
>>
>>e(3*l(120/75)) * 18.2
>>74.54719999999999999963
>>
>>about 75 hp.

> I'd query those figures: a decent 14bhp 125 will hit 75, and the
> original Honda CB750 did 120+ on a claimed 67bhp.

I didn't look too closely to figure out what sort of bike he was modeling.
Maybe it was a tourer with a big fairing and windshield. Actually,
my ZG1000 does about 127 tops, with 91 hp at the wheel, and using the
mythical 75mph/18.2hp bike as the model:

e(3*l(127.2/75)) * 18.2
88.78690795519999999818

It agrees rather well with their measured dyno reading of 91.0 hp peak,
assuming that the top speed actually occurred at the exact power peak,
which can't be guaranteed of course, due to gearing (I wonder if Mr.
CL360 will jump up and claim he can get my ZG to go another 10 or 20
mph faster if I change out the final drive :)

> Pretty close, though.

That's the point, it's close enough.
When the power required increases as the cube of the speed, and you
know you've got 34 hp at the most to work with, knowing a little bit of
1st year physics[2] won't let you wiggle out with a simple hand-wave.

It's easy enough for anyone who's ridden a few similar bikes up to their
real world top speeds, and knows where to dig up dyno numbers for them,
to conclusively prove that without major modifications to power output
or to the coefficient of drag, and/or frontal area, a similar bike isn't
going to magically be the lone exception to the laws of physics.

[1] 127 and 91 hp,
http://www.aquariumfish.com/mcn/model_eval/Kawasaki%20Concours,%20Part%204.pdf

[2] Of course if you don't know physics and can't do simple maths,
you can be untroubled by such concepts, and believe anything you want.

--
'01 SV650S '99 EX250-F13 '98 ZG1000-A13
OMF #7
The Older Gentleman
2007-03-16 21:27:26 UTC
Permalink
Raw Message
Mark Olson <***@tiny.invalid> wrote:

> It's easy enough for anyone who's ridden a few similar bikes up to their
> real world top speeds, and knows where to dig up dyno numbers for them,
> to conclusively prove that without major modifications to power output
> or to the coefficient of drag, and/or frontal area, a similar bike isn't
> going to magically be the lone exception to the laws of physics.

Yep.

I've owned *a lot* of small low-powered bikes. I just like playing with
them. In fact, I've just bought a 1974 Honda SL125, which I'm planning
to restore to "rather nice" condition....

Anyway, you don't even need to dig up the dyno numbers. After a while,
you hop on something and have a pretty good idea how it'll perform.

You still get exceptions to the rule - my 1988 Yamaha RD350 power-valve
was one. Christ, that was a fun bike. Claimed 60bhp: easily pulled into
the red in top, at an indicated 120+.

I actually geared it up, and it still pulled it (I'd heard it was
capable of doing so) but the "odd spot" at 6000 rpm (when the
power-valve was making its mind up whether to open or not) moved from
70+ mph to 75+, which made it a real pain, so I put the gearing back to
stock.

Thereby proving, I suppose, that the OE manufacturer usually gets it
right.


--
BMW K1100LT 750SS CB400F CD250 Z650
GAGARPHOF#30 GHPOTHUF#1 BOTAFOT#60 ANORAK#06 YTC#3
BOF#30 WUSS#5 The bells, the bells.....
Zaphod Beeblebrock
2007-03-17 20:00:14 UTC
Permalink
Raw Message
On Fri, 16 Mar 2007 15:19:31 -0500, Mark Olson wrote:

> (I wonder if Mr. CL360
> will jump up and claim he can get my ZG to go another 10 or 20 mph faster
> if I change out the final drive :)

No.

I don't know diddly squat about your machine or what modifications could
be done to it.

Yeah, I know, you're inclined to say that I don't know diddly squat about
_anything_.


--
Falcon's Rest
Zymurgical Alchemy
First Inter-Galactic Guild House Of
The Brotherhood Of St. Cathode Of Anode
The Older Gentleman
2007-03-17 20:01:11 UTC
Permalink
Raw Message
Zaphod Beeblebrock <***@TheUniverseTheRestaurant.com> wrote:

> Yeah, I know, you're inclined to say that I don't know diddly squat about
> _anything_.


The evidence for that is overwhelming.


--
BMW K1100LT 750SS CB400F CD250 Z650
GAGARPHOF#30 GHPOTHUF#1 BOTAFOT#60 ANORAK#06 YTC#3
BOF#30 WUSS#5 The bells, the bells.....
Rick Cortese
2007-03-16 21:36:29 UTC
Permalink
Raw Message
Mark Olson wrote:
> Rick Cortese wrote:
>
>> Let's use 120mph for terminal velocity => 633,600 ft/hour => 176 ft/sec.
>>
>> 1HP = 550ft lbs/sec.
>>
>> To keep it simple, bike + rider falling out of that airplane is 550
>> lbs. In my case an accurate estimate considering my non aerodynamic
>> lard ass. Assuming 120mph is terminal velocity, it would take 176hp to
>> push me and a Honda 360 that fast. Just too much crap like turn
>> signals and mirrors fluttering in the wind.
>
>
> Hmmm. How do the 300km/hr or 186 mph bikes (limited by manufacturer's
> agreement, some capable of exceeding 200 mph) get going that fast, with
> less than 176 hp?
>
>> Now you can plug any numbers you like in there. Say terminal velocity
>> is 240mph and it would only require 1/4 the HP to go 1/2 as fast, but
>> you are still talking 44HP. I think 240 is an optimistic terminal
>> velocity and some people may laugh at the thought of getting 44 rear
>> wheel HP out of a Honda 360, but heck, it could happen in an alternate
>> universe. The numbers will work out, I mean you can pretty much expect
>> an 11 hp bike to go ~60mph.
>
>
> Doesn't the power required to overcome aerodynamic drag increase as
> the cube of the velocity? <cheats, via google> Yep.

I am under the perhaps mistaken chemical engineering guesstimate of
flow. Flow in a pipe probably doesn't have as much to do with flow
around a motorcycle as I would like. I am going over to fellow chemist's
house this afternoon. He's a real chemical engineer with a resume that
includes Boeing vs. straight chemist such as myself. If he has anything
of value to add I will report back.
>
> This guy (if you squint hard) has a spreadsheet
>
> http://www.msgroup.org/forums/mtt/topic.asp?TOPIC_ID=869
>
> that says for some particular bike & rider, it takes 18.2 hp to go 75, so
> to go 120, it takes...
>
> e(3*l(120/75)) * 18.2
> 74.54719999999999999963
>
> about 75 hp.
>
> With 11 hp, that mythical bike would go about...
>
> 75 * (e(l(11/18.2)/3))
> 63.41154904466300639475
>
> 63 mph. You are a genius!
>
> Assuming our favorite bike, the CL360, with an advertised hp of 34 at the
> crank, IIRC, has all of that available at the rear wheel, and it's roughly
> the same frontal area and coefficient of drag:
>
> 75 * (e(l(34/18.2)/3))
> 92.36989283019552082575
>
> It's going to go about 90 mph tops.
>
> FURTHERMORE...
>
> 1/4 the hp to go 1/2 as fast? I think you mean 1/8 the hp to go 1/2 as
> fast.

I'll make it clear: No genus at this keyboard, so anything you see me
post is GUESSTIMATE! Your or anyone else's numbers are probably as good
as mine IMO.

*BUT* I remember seeing odd measurements of what drag is produced by
what equipment. Really so esoteric I can't imagine that anyone other
then myself would find it interesting. It was about drag in production
cars being reduced ~in half. They mentioned things like a conventional
1960s side mirror took the equivalent of 2hp to move through the air at
65mph. I wouldn't be surprised if motorcycles have undergone the same
reductions in drag what with partial fairings and what not.

I'm really that odd. I find the accounting for things like that
fascinating. Free float fan vs. fixed, 5hp to run your air
conditioning<on a car anyway>. I'm surprised I didn't tattoo the numbers
to my chest so I wouldn't lose it.<grin>

I mean when you can say side view mirror => 2hp at 65 and can calculate
the extra speed you would get by removing it... heaven is a place on
earth with a calculator, raw data, a number 2 pencil, and a blank sheet
of paper!
Mark Olson
2007-03-16 22:13:06 UTC
Permalink
Raw Message
Rick Cortese wrote:
> Mark Olson wrote:

>> Doesn't the power required to overcome aerodynamic drag increase as
>> the cube of the velocity? <cheats, via google> Yep.

> I am under the perhaps mistaken chemical engineering guesstimate of
> flow. Flow in a pipe probably doesn't have as much to do with flow
> around a motorcycle as I would like. I am going over to fellow chemist's
> house this afternoon. He's a real chemical engineer with a resume that
> includes Boeing vs. straight chemist such as myself. If he has anything
> of value to add I will report back.

The aerodynamic drag force increases as the square of the velocity, which
makes the power increase by the cube of V.

Despite Wikipedia's dubious reputation, I am pretty sure they've got
it correct, I didn't explicitly quote them before, but since the
question was raised:

http://en.wikipedia.org/wiki/Drag_%28aerodynamics%29#Power

(Apologies if the character encoding gets screwed up)

The power required to overcome the aerodynamic drag is given by:

Pd = Fd (dot product) v = -1/2 ρ v^3 A Cd

Fd is the force of drag,
ρ is the density of the fluid (Note that for the Earth's atmosphere,
the density can be found using the barometric formula. It is
1.293 kg/m3 at 0°C and 1 atmosphere.),
v is the velocity of the object relative to the fluid,
A is the reference area,
Cd is the drag coefficient (a dimensionless constant, e.g. 0.25 to 0.45 for a car), and
[v] is the unit vector indicating the direction of the velocity (the
negative sign indicating the drag is opposite to that of velocity).

The important bit is the v^3.

--
'01 SV650S '99 EX250-F13 '98 ZG1000-A13
OMF #7
Rick Cortese
2007-03-17 00:30:46 UTC
Permalink
Raw Message
Mark Olson wrote:
> Rick Cortese wrote:
>
>> Mark Olson wrote:
>
>
>>> Doesn't the power required to overcome aerodynamic drag increase as
>>> the cube of the velocity? <cheats, via google> Yep.
>
>
>> I am under the perhaps mistaken chemical engineering guesstimate of
>> flow. Flow in a pipe probably doesn't have as much to do with flow
>> around a motorcycle as I would like. I am going over to fellow
>> chemist's house this afternoon. He's a real chemical engineer with a
>> resume that includes Boeing vs. straight chemist such as myself. If he
>> has anything of value to add I will report back.
>
>
> The aerodynamic drag force increases as the square of the velocity, which
> makes the power increase by the cube of V.
>
> Despite Wikipedia's dubious reputation, I am pretty sure they've got
> it correct, I didn't explicitly quote them before, but since the
> question was raised:
>
> http://en.wikipedia.org/wiki/Drag_%28aerodynamics%29#Power
>
> (Apologies if the character encoding gets screwed up)
>
> The power required to overcome the aerodynamic drag is given by:
>
> Pd = Fd (dot product) v = -1/2 ρ v^3 A Cd
>
> Fd is the force of drag,
> ρ is the density of the fluid (Note that for the Earth's atmosphere,
> the density can be found using the barometric formula. It is
> 1.293 kg/m3 at 0°C and 1 atmosphere.),
> v is the velocity of the object relative to the fluid,
> A is the reference area,
> Cd is the drag coefficient (a dimensionless constant, e.g. 0.25 to
> 0.45 for a car), and
> [v] is the unit vector indicating the direction of the velocity (the
> negative sign indicating the drag is opposite to that of velocity).
>
> The important bit is the v^3.
>

OK, I think I am going to disagree with their numbers and analysis.

"Since power is the rate of doing work, four times a work in half the
time requires eight times the power."

I think this is wrong because of the distance component they add. I mean
this is important for mileage. If your car is burning 4 times as much
gas to go 60 miles per hour then at 30 miles per hour then you will be
using gas at 4 times the rate but for 1/2 as long or mileage would be
1/2 instead of 1/4. IMO: It should factor out in something stationary,
wind tunnel for instance.

There is no "in half the time" that needs to be factored the way they
did. It is four times the work in the same time. Distance is not
relevant except from an efficiency standpoint.

*BUT* once again, close enough for government work. I mean if you take
the derivative of it, it works out to 3/2pAC(v)^2. IOW: The
instantaneous slope/derivative is ~3/2pAC(v)^2 (small p for rho) by
their equation right? The numbers used for drag are in the range of .25
to .45 for a car, another set of numbers I contest as it is silly low to
represent a true crossection of cars on the road. It is the same cross
sectional area, drag, and the same media so they factor out. So you end
up with the slope/rate of change at any point on the plot will be
(3/2)(.45)(v)^2 or .675v^2. This is dangerously close to power being
v^2. The accuracy of using the slope vs. the full equation is valid if
you only use it over a narrow range. That is, going from 45 mph to 90
mph it is probably pretty good. Going from 45 mph to 450 mph it would
run into problems.

Rick
Mark Olson
2007-03-17 01:01:00 UTC
Permalink
Raw Message
Rick Cortese wrote:
> Mark Olson wrote:

>> http://en.wikipedia.org/wiki/Drag_%28aerodynamics%29#Power

>> The important bit is the v^3.
>>
>
> OK, I think I am going to disagree with their numbers and analysis.
>
> "Since power is the rate of doing work, four times a work in half the
> time requires eight times the power."

That's quite clear, (except for "times a work" should be "times THE
work") and I see nothing wrong with it.

> I think this is wrong because of the distance component they add. I mean
> this is important for mileage. If your car is burning 4 times as much
> gas to go 60 miles per hour then at 30 miles per hour then you will be
> using gas at 4 times the rate but for 1/2 as long or mileage would be
> 1/2 instead of 1/4. IMO: It should factor out in something stationary,
> wind tunnel for instance.

All I will say is in my experience, cars don't typically burn 4x as much
gas at 60 mph than they do at 30 mph... but it does indeed take 8x as
much power _to overcome aerodynamic drag_ at 60 mph as it does at 30 mph,
_assuming their equation holds true_ at those sorts of speeds.

The critical sentence in that paragraph gives them enough wiggle room
to push an elephant through:

"It should be emphasized here that the drag equation is an
approximation, and does not necessarily give a close approximation
in every instance. Thus one should be careful when making
assumptions using these equations."

I had stayed in Aero Engineering instead of the engineering major I
did pursue, I could talk about this with a bit more certainty, but I
am not in any doubt about the likelihood of a stock engined CL360
attaining 120mph without going downhill and/or pushed by a tailwind.

--
'01 SV650S '99 EX250-F13 '98 ZG1000-A13
OMF #7
Rick Cortese
2007-03-17 18:29:06 UTC
Permalink
Raw Message
Mark Olson wrote:

> Rick Cortese wrote:
>
>> Mark Olson wrote:
>
>
>>> http://en.wikipedia.org/wiki/Drag_%28aerodynamics%29#Power
>
>
>>> The important bit is the v^3.
>>>
>>
>> OK, I think I am going to disagree with their numbers and analysis.
>>
>> "Since power is the rate of doing work, four times a work in half the
>> time requires eight times the power."
>
>
> That's quite clear, (except for "times a work" should be "times THE
> work") and I see nothing wrong with it.
>
>> I think this is wrong because of the distance component they add. I
>> mean this is important for mileage. If your car is burning 4 times as
>> much gas to go 60 miles per hour then at 30 miles per hour then you
>> will be using gas at 4 times the rate but for 1/2 as long or mileage
>> would be 1/2 instead of 1/4. IMO: It should factor out in something
>> stationary, wind tunnel for instance.
>
>
> All I will say is in my experience, cars don't typically burn 4x as much
> gas at 60 mph than they do at 30 mph... but it does indeed take 8x as
> much power _to overcome aerodynamic drag_ at 60 mph as it does at 30 mph,
> _assuming their equation holds true_ at those sorts of speeds.

First I want to make it sure you know exactly where I am coming from.
Should just take a second.

I say power by square, that Wiki guy says power by cube with a fudge
factor. They have the approximately the same results over the interval
tested.

The truth may be somewhere in between.

I don't think his numbers fit well. Let's say a ~5hp scooter goes 35-40
mph which has been my experience. By his method you would need 40 hp to
do 70-80 mph which I think is high. Three times the speed or 105-120mph
would be 27x the hp or 135 hp. I think we all pretty much ack a 60-70hp
machine like a 750cc Honda will approach that. It gets even crazier when
you start going to 320 hp for 160 mph. I mean remember that guy in a
speedo laying down on a Vincent?

http://en.wikipedia.org/wiki/Rollie_Free

He approached that speed and a vintage Vincent puts out NOTHING like
320hp! My method is much closer to my own experience in that I would go
5, 20, 45, 80 hp respectively for 40ish, 80ish, 120ish, 150ish mph. My
estimate method may be bad but it certainly isn't worse. Who knows?
Maybe v^2.237 would be a better fit.

I just question why he uses that cube thing and the reasons he gives. It
isn't obvious to even a person that did it for a living at Boeing.

On to your statement about mileage, true the reason being at which RPM
an engine is designed to be most effiecent, but I can think of one
example off hand. On the series Mythbusters when they revisited one of
their mileage tests they used a flow meter to check mileage. As I recall
the numbers were very close to what I described if you calculated them
out. i.e. ~.7 gal/hour at 30 mph and ~2.6 gal/hour at 60 mph. I remember
thinking my square energy thing worked for their speed range => 4
times the energy to move at twice the rate, but they covered twice the
distance in that time so ~50% of the mileage. 30/.7 => 42 mpg, 60/2.6 =>
24 mpg. It was an SUV IIRC. It could have been 45 and 70 mph, it could
of been .9 and 2.4 gals, I really don't remember, just approximations.

I *think* it was on their show after being challenged about method where
they were testing with the air conditioner vs. windows rolled down to
see which produced the better milage. If I see the show again I will get
some hard numbers and/or tell you when it comes on.

But this factors out when we use top speed for a measurement. That is
the engines in question are running at their maximum output. A lot of
assumptions such as the gearing is right to produce maximum speed too.

I did see my Boeing ChemE friend and took exception to the cube in
Wikipedia. He went so far as to pull out one of his reference books and
show me the sections on flow. I glanced through it and didn't come
across any equations for flow that used the cube vs. the square. He said
that there are some models that use the cube and even some that use the
4th power but they are only used in flow through a small orifice/nozzle.

He suggested I look into 'Reynold's Number as that is what they used in
the wind tunnel at Boeing when he was there for testing models.

http://en.wikipedia.org/wiki/Reynolds_number

So engineer who worked at Boeing who said Reynolds is what they used, he
questioned cube in anything other then a nozzle/special case, chemical
engineering handbook, along with a Wikipedia reference that shows
Reynolds square vs. cube, I am sticking to my guns. I think the Wiki
Cube guy made a mistake if not several.

http://auto.howstuffworks.com/question477.htm

Uses square and cube with fudge factors. Once again, with fudge factors
that probably end up with approximately the same number as I use. Just
another hyperbola.

Once you've seen one hyperbola you've seen them all. Over a narrow range
there just isn't a big difference between the three [^2, ^3, av^2+bv^3]
forms.
Mark Olson
2007-03-17 18:38:06 UTC
Permalink
Raw Message
Rick Cortese wrote:
> Mark Olson wrote:
>
>> Rick Cortese wrote:
>>
>>> Mark Olson wrote:
>>
>>
>>
>>>> http://en.wikipedia.org/wiki/Drag_%28aerodynamics%29#Power
>>
>>
>>
>>>> The important bit is the v^3.
>>>>
>>>
>>> OK, I think I am going to disagree with their numbers and analysis.
>>>
>>> "Since power is the rate of doing work, four times a work in half the
>>> time requires eight times the power."
>>
>>
>>
>> That's quite clear, (except for "times a work" should be "times THE
>> work") and I see nothing wrong with it.
>>
>>> I think this is wrong because of the distance component they add. I
>>> mean this is important for mileage. If your car is burning 4 times as
>>> much gas to go 60 miles per hour then at 30 miles per hour then you
>>> will be using gas at 4 times the rate but for 1/2 as long or mileage
>>> would be 1/2 instead of 1/4. IMO: It should factor out in something
>>> stationary, wind tunnel for instance.
>>
>>
>>
>> All I will say is in my experience, cars don't typically burn 4x as much
>> gas at 60 mph than they do at 30 mph... but it does indeed take 8x as
>> much power _to overcome aerodynamic drag_ at 60 mph as it does at 30 mph,
>> _assuming their equation holds true_ at those sorts of speeds.
>
>
> First I want to make it sure you know exactly where I am coming from.
> Should just take a second.
>
> I say power by square, that Wiki guy says power by cube with a fudge
> factor. They have the approximately the same results over the interval
> tested.
>
> The truth may be somewhere in between.
>
> I don't think his numbers fit well. Let's say a ~5hp scooter goes 35-40
> mph which has been my experience. By his method you would need 40 hp to
> do 70-80 mph which I think is high. Three times the speed or 105-120mph
> would be 27x the hp or 135 hp. I think we all pretty much ack a 60-70hp
> machine like a 750cc Honda will approach that. It gets even crazier when
> you start going to 320 hp for 160 mph. I mean remember that guy in a
> speedo laying down on a Vincent?
>
> http://en.wikipedia.org/wiki/Rollie_Free
>
> He approached that speed and a vintage Vincent puts out NOTHING like
> 320hp! My method is much closer to my own experience in that I would go
> 5, 20, 45, 80 hp respectively for 40ish, 80ish, 120ish, 150ish mph. My
> estimate method may be bad but it certainly isn't worse. Who knows?
> Maybe v^2.237 would be a better fit.
>
> I just question why he uses that cube thing and the reasons he gives. It
> isn't obvious to even a person that did it for a living at Boeing.
>
> On to your statement about mileage, true the reason being at which RPM
> an engine is designed to be most effiecent, but I can think of one
> example off hand. On the series Mythbusters when they revisited one of
> their mileage tests they used a flow meter to check mileage. As I recall
> the numbers were very close to what I described if you calculated them
> out. i.e. ~.7 gal/hour at 30 mph and ~2.6 gal/hour at 60 mph. I remember
> thinking my square energy thing worked for their speed range => 4 times
> the energy to move at twice the rate, but they covered twice the
> distance in that time so ~50% of the mileage. 30/.7 => 42 mpg, 60/2.6 =>
> 24 mpg. It was an SUV IIRC. It could have been 45 and 70 mph, it could
> of been .9 and 2.4 gals, I really don't remember, just approximations.
>
> I *think* it was on their show after being challenged about method where
> they were testing with the air conditioner vs. windows rolled down to
> see which produced the better milage. If I see the show again I will get
> some hard numbers and/or tell you when it comes on.
>
> But this factors out when we use top speed for a measurement. That is
> the engines in question are running at their maximum output. A lot of
> assumptions such as the gearing is right to produce maximum speed too.
>
> I did see my Boeing ChemE friend and took exception to the cube in
> Wikipedia. He went so far as to pull out one of his reference books and
> show me the sections on flow. I glanced through it and didn't come
> across any equations for flow that used the cube vs. the square. He said
> that there are some models that use the cube and even some that use the
> 4th power but they are only used in flow through a small orifice/nozzle.
>
> He suggested I look into 'Reynold's Number as that is what they used in
> the wind tunnel at Boeing when he was there for testing models.
>
> http://en.wikipedia.org/wiki/Reynolds_number
>
> So engineer who worked at Boeing who said Reynolds is what they used, he
> questioned cube in anything other then a nozzle/special case, chemical
> engineering handbook, along with a Wikipedia reference that shows
> Reynolds square vs. cube, I am sticking to my guns. I think the Wiki
> Cube guy made a mistake if not several.
>
> http://auto.howstuffworks.com/question477.htm
>
> Uses square and cube with fudge factors. Once again, with fudge factors
> that probably end up with approximately the same number as I use. Just
> another hyperbola.
>
> Once you've seen one hyperbola you've seen them all. Over a narrow range
> there just isn't a big difference between the three [^2, ^3, av^2+bv^3]
> forms.

Hey, I have to admit that I am not married to the idea of power increasing
by the cube of the velocity. It wouldn't be the first time someone put up
impressive-looking BS on Wikipedia.

After doing a few sample calcs of my own it blows up pretty quickly into
the ridiculous range for real world examples of 300 km/hr bikes that make
about 150+ hp. So you are probably right when you say it's something
between the 2nd and 3rd power for the velocities and bike-shaped objects
that we are interested in.

Thanks for an interesting discussion.

--
'01 SV650S '99 EX250-F13 '98 ZG1000-A13
OMF #7
The Older Gentleman
2007-03-17 19:30:55 UTC
Permalink
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Mark Olson <***@tiny.invalid> wrote:

> Thanks for an interesting discussion.

May I second that? All this maths goes way over my head, bud it's always
interesting to see a well-reasoned argument.


--
BMW K1100LT 750SS CB400F CD250 Z650
GAGARPHOF#30 GHPOTHUF#1 BOTAFOT#60 ANORAK#06 YTC#3
BOF#30 WUSS#5 The bells, the bells.....
Zaphod Beeblebrock
2007-03-18 16:00:25 UTC
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Raw Message
On Sat, 17 Mar 2007 19:30:55 +0000, The Older Gentleman wrote:

> Mark Olson <***@tiny.invalid> wrote:
>
>> Thanks for an interesting discussion.
>
> May I second that? All this maths goes way over my head, bud it's always
> interesting to see a well-reasoned argument.

LOL, to think you might have missed out if I weren't so "ignorant" and
such a "stupid sod".

--
Falcon's Rest
Zymurgical Alchemy
First Inter-Galactic Guild House Of
The Brotherhood Of St. Cathode Of Anode
The Older Gentleman
2007-03-18 16:26:48 UTC
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Zaphod Beeblebrock <***@TheUniverseTheRestaurant.com> wrote:

> On Sat, 17 Mar 2007 19:30:55 +0000, The Older Gentleman wrote:
>
> > Mark Olson <***@tiny.invalid> wrote:
> >
> >> Thanks for an interesting discussion.
> >
> > May I second that? All this maths goes way over my head, bud it's always
> > interesting to see a well-reasoned argument.
>
> LOL, to think you might have missed out if I weren't so "ignorant" and
> such a "stupid sod".

You are.

As has been noted, you display an ignorance that's truly impressive. The
refusal to acknowledge that means your stupidity is just as impressive.


--
BMW K1100LT 750SS CB400F CD250 Z650
GAGARPHOF#30 GHPOTHUF#1 BOTAFOT#60 ANORAK#06 YTC#3
BOF#30 WUSS#5 The bells, the bells.....
oldgeezer
2007-03-17 00:38:53 UTC
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On Mar 16, 11:13 pm, Mark Olson <***@tiny.invalid> wrote:
> Rick Cortese wrote:
> > Mark Olson wrote:
> >> Doesn't the power required to overcome aerodynamic drag increase as
> >> the cube of the velocity?  <cheats, via google>  Yep.
> > I am under the perhaps mistaken chemical engineering guesstimate of
> > flow. Flow in a pipe probably doesn't have as much to do with flow
> > around a motorcycle as I would like. I am going over to fellow chemist's
> > house this afternoon. He's a real chemical engineer with a resume that
> > includes Boeing vs. straight chemist such as myself. If he has anything
> > of value to add I will report back.
>
> The aerodynamic drag force increases as the square of the velocity, which
> makes the power increase by the cube of V.
>
> Despite Wikipedia's dubious reputation, I am pretty sure they've got
> it correct, I didn't explicitly quote them before, but since the
> question was raised:
>
> http://en.wikipedia.org/wiki/Drag_%28aerodynamics%29#Power
>
> (Apologies if the character encoding gets screwed up)
>
> The power required to overcome the aerodynamic drag is given by:
>
>      Pd = Fd (dot product) v = -1/2 ρ v^3 A Cd
>
>      Fd is the force of drag,
>      ρ is the density of the fluid (Note that for the Earth's atmosphere,
>        the density can be found using the barometric formula. It is
>         1.293 kg/m3 at 0°C and 1 atmosphere.),
>      v is the velocity of the object relative to the fluid,
>      A is the reference area,
>      Cd is the drag coefficient (a dimensionless constant, e.g. 0.25 to 0.45 for a car), and
>      [v] is the unit vector indicating the direction of the velocity (the
>      negative sign indicating the drag is opposite to that of velocity).
>
> The important bit is the v^3.
>
> --
> '01 SV650S  '99 EX250-F13  '98 ZG1000-A13
> OMF #7

They tought me that some 40 years ago.
It still is correct.

Cd relates to the shape of the body. A square block
has a higher Cd-value than a smoothly curved
shape.

btw, the CD-value for a body is simply measured (in a wind tunnel).
They place the body in an airstream and
measure the force needed to keep it
in place.
Cd is then calcultated by
dividing that force by
'half rho v-squared times A' (I cannot type
better than this).

The term 'reference area' sounds
a bit misleading to me.
It is just the area of the cross section in the wind. Like the frontal
area of a car. Or the frontal area of you and
the bike together. In square meters.

Laying flat on the bike thus helps in
two ways. You lower both Cd and A.

It always amuses me when a car manufacturer
proudly states a low Cd for the car, and forgets
to mention anything about
the A.
The Older Gentleman
2007-03-17 08:35:41 UTC
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Raw Message
Rick Cortese <***@earthlink.net> wrote:

> I mean when you can say side view mirror => 2hp at 65

See my remark about removing the mirrors when speed-testing bikes.


--
BMW K1100LT 750SS CB400F CD250 Z650
GAGARPHOF#30 GHPOTHUF#1 BOTAFOT#60 ANORAK#06 YTC#3
BOF#30 WUSS#5 The bells, the bells.....
The Older Gentleman
2007-03-16 19:44:49 UTC
Permalink
Raw Message
Rick Cortese <***@earthlink.net> wrote:

> Physics works and in the absence of a miracle I
> trust it.

Amen.


--
BMW K1100LT 750SS CB400F CD250 Z650
GAGARPHOF#30 GHPOTHUF#1 BOTAFOT#60 ANORAK#06 YTC#3
BOF#30 WUSS#5 The bells, the bells.....
Zaphod Beeblebrock
2007-03-17 14:39:57 UTC
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On Fri, 16 Mar 2007 17:40:48 +0000, Rick Cortese wrote:


> I seem to recall a girl on 175 2smoke getting up to ~154. Her father built
> the bike and she looked like she weighed maybe a buck 10. But to get to
> that speed it was about as far away from stock as you could get w/o going
> to a full streamliner/belly tank. The bike had full fairing and she was in
> a speed suit with aerodynamic helmet.
>
> I mention that 175 as a somewhat known quantity. Probably puts out about
> the same HP as a really highly tuned 350ish OHC 4 stroke. The point is it
> takes engine modifications, streamlining, and a pint sized rider to get to
> that speed.
>
> The problem I have with a stock bike going that fast vs. what I think
> happened<you had a very optimistic speedo> isn't just the HP so much as
> the drag at that speed. There's a guy who did several articles for IIRC
> Motorcycle Shopper which you may want to look at for just exactly how much
> modification was required. He has before and after picts of the heads and
> the stock Hondas were pretty restricted. Yeap, you could have had a hot
> one where the previous owner hogged out the head, replaced cam and valve
> springs, et cetera.
>
> Why I feel this way without personally seeing you ride that bike is I've
> been to 110 mph and everything gets light and squirrelly. Frightening
> would be more like it. At 120 you are pretty much at what may be terminal
> velocity if you were dropped out of a plane. IOW: 1g of air resistance.
> The coefficient of friction of a tire of that era was probably around
> .75g. This is a common problem<ibid physics> with all wheel driven
> vehicles i.e. the other reason why they put wings on everything from
> dragsters to formula one cars. It isn't just traction though, you have a
> tendency to get light and flutter like a leaf in the wind at that speed.

I don't happen to think that 120 is a particularly outrageous speed, and
you'd need to put airplane wings on the thing in order to get enough lift
to worry about getting light. A bike isn't much more aerodynamic than a
brick. A 200+mph F1 car, yeah, you want a little down-pressure
to get your tires to stick a little better in the turns...

On a bike, in a straight line under 150mph, the friction coefficient of
the tires isn't particularly relevant. NASCAR drivers run around, what,
180-190(?) and I don't recollect seeing much in the way of wings on them.
Some ground-effects stuff maybe.

If you wanted to talk about how tight a turn one could make at 120mph,
using the street tire rubber compounds that were available 30 years ago,
well, friction coefficient would factor in. But not in a straight line.

> Let's use 120mph for terminal velocity => 633,600 ft/hour => 176 ft/sec.
>
> 1HP = 550ft lbs/sec.
>
> To keep it simple, bike + rider falling out of that airplane is 550 lbs.
> In my case an accurate estimate considering my non aerodynamic lard
> ass. Assuming 120mph is terminal velocity, it would take 176hp to push me
> and a Honda 360 that fast. Just too much crap like turn signals and
> mirrors fluttering in the wind.

Your calculations are incorrect because you are starting with a faulty
premise. Wind resistance is not a primary factor in terminal velocity in a
non-aerodynamic object. An ordinary red brick would have considerably more
wind resistance than a perfectly round lead sphere, would it not? But if
you drop them from the same height, at the same time they will both reach
terminal velocity at the same time and hit the ground at the same time.

Frankly, 120mph isn't all that fast and it really didn't take any
engineering or mechanical wizardry to reach it with that machine, just a
simple sprocket/chain change to get a little more out of the top end.

If I had had any inkling that a bunch of otherwise supposedly
knowledgeable people in a "tech" newsgroup would take the stand that this
relatively easy feat was a ludicrous impossibility and start a shitstorm
of pronouncements that "it couldn't be done", I'd have kept silent.

Would I start another shitstorm if I said the same modification to a
Suzuku TS100 would get it to 85mph?


> Now you can plug any numbers you like in there. Say terminal velocity is
> 240mph and it would only require 1/4 the HP to go 1/2 as fast, but you are
> still talking 44HP. I think 240 is an optimistic terminal velocity and
> some people may laugh at the thought of getting 44 rear wheel HP out of a
> Honda 360, but heck, it could happen in an alternate universe. The numbers
> will work out, I mean you can pretty much expect an 11 hp bike to go
> ~60mph.

It doesn't matter what numbers you plug in, your answer will be
meaningless because the starting assumption is incorrect.

I am *amazed* at how many people are jumping to tell me I'm full of shit,
while backing that up with nothing more than theoretical musings of how
"it can't be done", instead of coming up with some actual, FACTUAL
information on this machine such as the original factory specs from the
manual such as horsepower, speed, gearing and ratios and the number of
teeth on the stock rear sprocket.

Armed with that information, it would be a relatively simple task to
calculate just how little (or much) effort it takes to do what I said.
Since it's been 30+ years, I can't be *completely* sure, but I think that
I used a sprocket that had only 6 or 8 fewer teeth. Then you all could
really pound me into the sand with REAL info instead of bullshit...or is
everybody here unwilling to get the real facts because they might be shown
to be wrong?

To that end, I have located someone who owns one of these machines and
requested that he send me any available info. I will also check any other
sources I can find such as the local Honda shop, etc.

--
Falcon's Rest
Zymurgical Alchemy
First Inter-Galactic Guild House Of
The Brotherhood Of St. Cathode Of Anode
The Older Gentleman
2007-03-17 15:11:04 UTC
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Zaphod Beeblebrock <***@TheUniverseTheRestaurant.com> wrote:

> Frankly, 120mph isn't all that fast and it really didn't take any
> engineering or mechanical wizardry to reach it with that machine, just a
> simple sprocket/chain change to get a little more out of the top end.

Nonsense. It still won't do 120mph without a very steep hill and a
hurricane tailwind. Do you *really* think that a sprocket change makes
it as fast a CB750?

>
> If I had had any inkling that a bunch of otherwise supposedly
> knowledgeable people in a "tech" newsgroup would take the stand that this
> relatively easy feat was a ludicrous impossibility and start a shitstorm
> of pronouncements that "it couldn't be done", I'd have kept silent.

We wish.

You are still, and it grieves me to say this, full of shit.

--
BMW K1100LT 750SS CB400F CD250 Z650
GAGARPHOF#30 GHPOTHUF#1 BOTAFOT#60 ANORAK#06 YTC#3
BOF#30 WUSS#5 The bells, the bells.....
Rick Cortese
2007-03-17 16:28:26 UTC
Permalink
Raw Message
Zaphod Beeblebrock wrote:
> On Fri, 16 Mar 2007 17:40:48 +0000, Rick Cortese wrote:
<snip>
> Your calculations are incorrect because you are starting with a faulty
> premise. Wind resistance is not a primary factor in terminal velocity in a
> non-aerodynamic object. An ordinary red brick would have considerably more
> wind resistance than a perfectly round lead sphere, would it not? But if
> you drop them from the same height, at the same time they will both reach
> terminal velocity at the same time and hit the ground at the same time.

One more time and I am as serious as a broken leg on this. If you can
really ride a production 350 anything to those speeds, go set the land
speed record. I mean you could probably own everything from vintage
class to late models.

BTW: Will also respond to Mark, my ChemE friend gave a "whaaa???" and a
puzzled look on his face when I mentioned Wikipedia said resistance
cubed for the calculation. He went to his reference books to show me
that he thought it was squared too. He said the only time things go to
cube or 4th power is in things like a spray nozzle or pin hole.
<snip>
>>Now you can plug any numbers you like in there. Say terminal velocity is
>>240mph and it would only require 1/4 the HP to go 1/2 as fast, but you are
>>still talking 44HP. I think 240 is an optimistic terminal velocity and
>>some people may laugh at the thought of getting 44 rear wheel HP out of a
>>Honda 360, but heck, it could happen in an alternate universe. The numbers
>>will work out, I mean you can pretty much expect an 11 hp bike to go
>>~60mph.
>
>
> It doesn't matter what numbers you plug in, your answer will be
> meaningless because the starting assumption is incorrect.

And you are?

Got a pHd in aeronautical engineering or a space shuttle pilot or something?

You are being kind of a real asshole here. I mean I have said
guesstimate and everyone elses numbers are as valid as mine and you
attack my comments as meaningless and incorrect?
>
> I am *amazed* at how many people are jumping to tell me I'm full of shit,
> while backing that up with nothing more than theoretical musings of how
> "it can't be done",

Wrongo. I have never said anything but guesstimate. I stand by my
estimates/guesstimates. You really kind of piss me off as I have bent
over backwards trying to give you wiggle room. I have said stuff to the
effect that maybe a previous owner modified the bike et cetera. This
does not speak well of you by choosing to attack the only guy who was
doing this for you. I take back every bit of wiggle room I gave you now
and apologize to other group members for doing it.

I have never said you are full of shit. I have always had a show
me/prove it/something else i.e. badly calibrated speedo had to account
for it.

I have repeatedly said prove it. By definition this makes me a
experimentalist vs. a theorist.

> instead of coming up with some actual, FACTUAL
> information on this machine such as the original factory specs from the
> manual such as horsepower, speed, gearing and ratios and the number of
> teeth on the stock rear sprocket.

I was the one who brought the motorcycle LSR into the discussion. You
can't get much harder facts and numbers then those. Further I think
someone posted raw HP for at least a CB350.
>
> Armed with that information, it would be a relatively simple task to
> calculate just how little (or much) effort it takes to do what I said.
> Since it's been 30+ years, I can't be *completely* sure, but I think that
> I used a sprocket that had only 6 or 8 fewer teeth. Then you all could
> really pound me into the sand with REAL info instead of bullshit...or is
> everybody here unwilling to get the real facts because they might be shown
> to be wrong?

LSR ibid.
>
> To that end, I have located someone who owns one of these machines and
> requested that he send me any available info. I will also check any other
> sources I can find such as the local Honda shop, etc.
>
Mark Olson
2007-03-17 17:02:36 UTC
Permalink
Raw Message
Rick Cortese wrote:

> BTW: Will also respond to Mark, my ChemE friend gave a "whaaa???" and a
> puzzled look on his face when I mentioned Wikipedia said resistance
> cubed for the calculation. He went to his reference books to show me
> that he thought it was squared too. He said the only time things go to
> cube or 4th power is in things like a spray nozzle or pin hole.

Drag _resistance_ (force) does indeed go up by the square of the
velocity. Power consumed by aerodynamic drag goes up by the third
power of velocity, since

Power (scalar) = Force (vector) (dot product) velocity (vector).

This isn't the first time I've seen the v^3 relationship, unfortunately
I don't know any aeronautical engineers personally or I'd ask one. I
do know well a couple of ChemEs, many MechEs, and I've asked a couple,
so far no one has contradicted Wikipedia's formulae.

Again, the disclaimer on Wikipedia's page leaves a hole big enough to
drive a dump truck through, their simple formula is only correct for
'some' ranges of viscosity, shape, velocities, etc.

--
'01 SV650S '99 EX250-F13 '98 ZG1000-A13
OMF #7
The Older Gentleman
2007-03-17 17:04:16 UTC
Permalink
Raw Message
Rick Cortese <***@earthlink.net> wrote:

> I have never said you are full of shit. I

Er, that was me.... ;-)

>
> Further I think
> someone posted raw HP for at least a CB350.

Er, that was me. For a 360, anyway.


--
BMW K1100LT 750SS CB400F CD250 Z650
GAGARPHOF#30 GHPOTHUF#1 BOTAFOT#60 ANORAK#06 YTC#3
BOF#30 WUSS#5 The bells, the bells.....
Zaphod Beeblebrock
2007-03-17 21:21:43 UTC
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On Sat, 17 Mar 2007 16:28:26 +0000, Rick Cortese wrote:

> You are being kind of a real asshole here. I mean I have said guesstimate
> and everyone elses numbers are as valid as mine and you attack my comments
> as meaningless and incorrect?

I apologize if it appeared to be an attack. I just feel that the use of
the term "terminal velocity" is not correct in this discussion. As I
understand the usage of "terminal velocity", it refers to the speed to
which an object will accelerate (at a rate of 32 feet/sec/sec) when
dropped from a sufficient height.

To me, assuming that "terminal velocity" has anything to do with the
discussion is a faulty premise and renders any equations meaningless.

If I misunderstood what you were trying to say, again, I apologize.

Yes, I realize that you are the one who has been giving the greatest
latitude in this discussion, and I appreciate it.

No, I do not have a degree. I do have, however, *some* education in
various disciplines as well as practical experience.

I might concede that two speedometers could be off by some percentage, but
not by a huge margin. I didn't check their calibration. But I will go to
my grave swearing that that both of those machines would reach an
"indicated" (a term someone else used elsewhere in this thread) 120mph.
When it comes to something *I* experienced*, something that I saw with my
own eyes, I will not be convinced that it didn't happen no matter how many
numbers are thrown out to say it "didn't" happen. Yeah, I put the motors
way past redline.

After reading some of the other responses I realize that the speedos
*could* have been off and lacking any calibration data I should not be
saying it was an "absolutely guaranteed 120mph". But how much error are we
talking about here?

I certainly didn't intend to start a shitstorm like this. I only wanted to
say that those were some pretty damn good motors as far as I was
concerned. But insinuating that I'm a liar and being flamed as a "stupid
sod"? I damned sure would have kept silent had I known this would happen.

That speedo hit 120, and broke there. The cops were pissed about all of
the time they spent looking for my body because, as bad as the bike looked
after the wreck, they didn't think the rider could have survived, let
alone leave the scene under his own power.

--
Falcon's Rest
Zymurgical Alchemy
First Inter-Galactic Guild House Of
The Brotherhood Of St. Cathode Of Anode
The Older Gentleman
2007-03-17 22:06:07 UTC
Permalink
Raw Message
Zaphod Beeblebrock <***@TheUniverseTheRestaurant.com> wrote:

> I should not be
> saying it was an "absolutely guaranteed 120mph". But how much error are we
> talking about here?

10-15%. At an indicated 120mph, that means a true top speed of as little
as 103mph, and that under "favourable" conditions.



--
BMW K1100LT 750SS CB400F CD250 Z650
GAGARPHOF#30 GHPOTHUF#1 BOTAFOT#60 ANORAK#06 YTC#3
BOF#30 WUSS#5 The bells, the bells.....
Gene Cash
2007-03-17 08:49:59 UTC
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Zaphod Beeblebrock <***@TheUniverseTheRestaurant.com> writes:

> I've owned a couple of the early '70s CL360s and, after a bit of
> tinkering[1], could get them up past 120mph. Carrying a passenger was
> never a problem either...but, I only weigh about 140lbs and it doesn't
> take too many horses to pull my bean-pole bod down the road.
> (Unfortunately, even at that light weight they don't fly very well, even
> at 120+mph, after leaving said road on a banked curve. They aren't much
> good for riding on afterward, either.)
>
> [1]The tinkering was mostly just fine-tuning the motor and changing the
> rear sprocket and the chain.

Oh crikey. How did this twit escape from my killfile?

Did the "tinkering" also include painting new numbers on the speedometer?

-gc

--
I'm so old I remember when you got manuals with your software.
The Older Gentleman
2007-03-17 09:19:00 UTC
Permalink
Raw Message
Gene Cash <***@autobogonzap.cfl.rr.com> wrote:

> Oh crikey. How did this twit escape from my killfile?

<VVBG>

>
> Did the "tinkering" also include painting new numbers on the speedometer?

Heh. welcome to the party.


--
BMW K1100LT 750SS CB400F CD250 Z650
GAGARPHOF#30 GHPOTHUF#1 BOTAFOT#60 ANORAK#06 YTC#3
BOF#30 WUSS#5 The bells, the bells.....
Rick Cortese
2007-03-13 17:54:41 UTC
Permalink
Raw Message
Ig wrote:
> Greetings. I have a general question and very much grateful for any
> feedback.
> I have recently moved from the flat midwest to the hilly san francisco
> area.
> I found a beautiful deal on a 73 Honda cb350... I realize that these
> engines need constant tinkering. that is not the problem, this one has
> low milage and lots of life still left.
> My question is whether a 350 engine can generate enough juice to be
> more than just a recreational bike. I would love to become the owner
> of this if it can actually be expected to climb some hills (and even
> carry a pasenger). Is this just wishful thinking?
> Back in chicago i was riding a 76 CB750.. Not looking for lots of of
> power necessarily, just functionality. what do you think?
> Thanks in advance.
> IR
>

Amoung other problems IIRC: you have to remember the 350 was really only
a ~323cc bike. There's only so much water in the well.

I thought by '73 they switched from CV to regular carbs which derated
the engine a bit. If it has the CV carbs, the good news is it probably
produces a few more HP then later models. The bad news is the silicon
diaphrams in those go out. In any case if it is running right you can
expect speeds in the 70-80 MPH range.

The 350s do seem to have their fan base. I think a ~1971 350SL recently
sold for ~$10k.
.***@see_my_sig_for_address.com
2007-03-13 20:14:14 UTC
Permalink
Raw Message
On Tue, 13 Mar 2007 17:54:41 GMT, Rick Cortese
<***@earthlink.net> wrote:

>Ig wrote:
>> Greetings. I have a general question and very much grateful for any
>> feedback.
>> I have recently moved from the flat midwest to the hilly san francisco
>> area.
>> I found a beautiful deal on a 73 Honda cb350... I realize that these
>> engines need constant tinkering. that is not the problem, this one has
>> low milage and lots of life still left.
>> My question is whether a 350 engine can generate enough juice to be
>> more than just a recreational bike. I would love to become the owner
>> of this if it can actually be expected to climb some hills (and even
>> carry a pasenger). Is this just wishful thinking?
>> Back in chicago i was riding a 76 CB750.. Not looking for lots of of
>> power necessarily, just functionality. what do you think?
>> Thanks in advance.
>> IR
>>
>
>Amoung other problems IIRC: you have to remember the 350 was really only
>a ~323cc bike. There's only so much water in the well.
>
>I thought by '73 they switched from CV to regular carbs which derated
>the engine a bit. If it has the CV carbs, the good news is it probably
>produces a few more HP then later models. The bad news is the silicon
>diaphrams in those go out. In any case if it is running right you can
>expect speeds in the 70-80 MPH range.
>
>The 350s do seem to have their fan base. I think a ~1971 350SL recently
>sold for ~$10k.

Ummm... yeh.

But that's a Mercedes convertible sports coupe.


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The Older Gentleman
2007-03-13 19:47:24 UTC
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Raw Message
<***@see_my_sig_for_address.com> wrote:

> >The 350s do seem to have their fan base. I think a ~1971 350SL recently
> >sold for ~$10k.
>
> Ummm... yeh.
>
> But that's a Mercedes convertible sports coupe.

<VVVBG>


--
BMW K1100LT 750SS CB400F CD250 Z650
GAGARPHOF#30 GHPOTHUF#1 BOTAFOT#60 ANORAK#06 YTC#3
BOF#30 WUSS#5 The bells, the bells.....
samual.witkamp@gmail.com
2015-08-05 17:52:29 UTC
Permalink
Raw Message
On Tuesday, March 13, 2007 at 1:54:41 PM UTC-4, ricortes wrote:
> Ig wrote:
> > Greetings. I have a general question and very much grateful for any
> > feedback.
> > I have recently moved from the flat midwest to the hilly san francisco
> > area.
> > I found a beautiful deal on a 73 Honda cb350... I realize that these
> > engines need constant tinkering. that is not the problem, this one has
> > low milage and lots of life still left.
> > My question is whether a 350 engine can generate enough juice to be
> > more than just a recreational bike. I would love to become the owner
> > of this if it can actually be expected to climb some hills (and even
> > carry a pasenger). Is this just wishful thinking?
> > Back in chicago i was riding a 76 CB750.. Not looking for lots of of
> > power necessarily, just functionality. what do you think?
> > Thanks in advance.
> > IR
> >
>
> Amoung other problems IIRC: you have to remember the 350 was really only
> a ~323cc bike. There's only so much water in the well.
>
> I thought by '73 they switched from CV to regular carbs which derated
> the engine a bit. If it has the CV carbs, the good news is it probably
> produces a few more HP then later models. The bad news is the silicon
> diaphrams in those go out. In any case if it is running right you can
> expect speeds in the 70-80 MPH range.
>
> The 350s do seem to have their fan base. I think a ~1971 350SL recently
> sold for ~$10k.

i own a 1971 350cb and ive had it up to 95 mph
Futility Man
2015-08-06 00:39:20 UTC
Permalink
Raw Message
On Wed, 5 Aug 2015 10:52:29 -0700 (PDT), "***@gmail.com"
<***@gmail.com> wrote:

>i own a 1971 350cb and ive had it up to 95 mph

You also just replied to an 8 year old pissing contest that was over long ago.
But I'm sure they're glad to hear from you.

I had a '74 CB360 and while it would eventually do 90 with a light passenger, I
wouldn't want to do it very often. And I doubt if it would do 100.

--
Futility Man
Kevin Bottorff
2015-08-06 20:45:20 UTC
Permalink
Raw Message
Futility Man <***@futile.org> wrote in
news:***@4ax.com:

> On Wed, 5 Aug 2015 10:52:29 -0700 (PDT), "***@gmail.com"
> <***@gmail.com> wrote:
>
>>i own a 1971 350cb and ive had it up to 95 mph
>
> You also just replied to an 8 year old pissing contest that was over
> long ago. But I'm sure they're glad to hear from you.
>
> I had a '74 CB360 and while it would eventually do 90 with a light
> passenger, I wouldn't want to do it very often. And I doubt if it
> would do 100.
>
> --
> Futility Man
>

yea the 360 had a poor frame, pretty loose. KB
M***@yahoo.com
2007-03-14 23:37:43 UTC
Permalink
Raw Message
On Mar 13, 12:17 am, "Ig" <***@gmail.com> wrote:
> Greetings. I have a general question and very much grateful for any
> feedback.
> I have recently moved from the flat midwest to the hilly san francisco
> area.
> I found a beautiful deal on a 73 Honda cb350... I realize that these
> engines need constant tinkering. that is not the problem, this one has
> low milage and lots of life still left.
> My question is whether a 350 engine can generate enough juice to be
> more than just a recreational bike. I would love to become the owner
> of this if it can actually be expected to climb some hills (and even
> carry a pasenger). Is this just wishful thinking?
> Back in chicago i was riding a 76 CB750.. Not looking for lots of of
> power necessarily, just functionality. what do you think?
> Thanks in advance.
> IR

More than 'just a recreational bike`? Thats all the 350 was.
Two up on Frisco hills? - It'll get you there, even with a passenger,
but you'll have to do some fancy clutchwork & shifting.
If you're coming off a 750, you probably won't enjoy it, and if
you're
over 5' 9" or so, you might feel folded kinda small.

O.T. That coast highway is a ride not to be missed, you luck dog you.

MadDog
holysmokes via MotorcycleKB.com
2007-03-17 20:14:42 UTC
Permalink
Raw Message
stock gearing is calculated to allow the power band to be fully utilized in
highway speeds

over gearing a bike engine will overheat the crank bearings and kill the
engine

I have owned afew 350 hondas, 65 mph is a comfortable spped for them, 1 up,
get on the highway, 2 up, come to a steep hill and all is lost, I presently
have a 1980 750 custom, 4cylinder 80 hp

top speed 115, if i went beserk and increased gearing. it would do 120mph +,
but it isnt meant or built for that speed

a 350 in a high speed traffic situation will get you run over, around the
city,1 up, itll be okay,

***@yahoo.com wrote:
>> Greetings. I have a general question and very much grateful for any
>> feedback.
>[quoted text clipped - 11 lines]
>> Thanks in advance.
>> IR
>
>More than 'just a recreational bike`? Thats all the 350 was.
>Two up on Frisco hills? - It'll get you there, even with a passenger,
>but you'll have to do some fancy clutchwork & shifting.
>If you're coming off a 750, you probably won't enjoy it, and if
>you're
>over 5' 9" or so, you might feel folded kinda small.
>
>O.T. That coast highway is a ride not to be missed, you luck dog you.
>
>MadDog

--
Message posted via http://www.motorcyclekb.com
The Older Gentleman
2007-03-17 22:06:07 UTC
Permalink
Raw Message
"holysmokes via MotorcycleKB.com" <***@uwe> wrote:

> over gearing a bike engine will overheat the crank bearings and kill the
> engine

Fuck me sideways, this thread is bringing out every ignoramus on the
planet.


--
BMW K1100LT 750SS CB400F CD250 Z650
GAGARPHOF#30 GHPOTHUF#1 BOTAFOT#60 ANORAK#06 YTC#3
BOF#30 WUSS#5 The bells, the bells.....
Grizz
2007-03-20 14:44:21 UTC
Permalink
Raw Message
Ig wrote:
...
> My question is whether a 350 engine can generate enough juice to be
> more than just a recreational bike. I would love to become the owner
> of this if it can actually be expected to climb some hills (and even
> carry a pasenger). Is this just wishful thinking?
> Back in chicago i was riding a 76 CB750.. Not looking for lots of of
> power necessarily, just functionality. what do you think?
> Thanks in advance.
> IR
>

My first reliable bike (after a short lived Kawasaki A1, SN A1 00000
fifty something that melted it's engine)
was a KZ400, my friend had a CB350 and we took a road trip around the
north end of lake Superior together.

For the first several days I wondered why my friend always wanted
a rest stop before I needed one ... then we switched bikes.

The 350 was fine up to about 50 MPH, but at higher speeds it had
too much engine vibration, wasn't comfortable to ride on the highway.
Would be a fine city bike but I wouldn't get it if you're planning
on spending much time at highway speeds. We were normally traveling
about 75 MPH, my KZ400 was smooth at that speed, but the CB350 would
buzz yer kidneys off.
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