Discussion:
Clutch slips. Discs or springs?
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mike
2017-07-01 00:13:46 UTC
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Clutch slips. Discs or springs?

I have a 1983 Honda Shadow VT500C.
The clutch slips at full throttle. I'm using 20W50 oil to keep the
valve train noise down, and that doesn't help.

About 20 years ago, with the original engine, I had the same problem.
The clutch disc thickness was within the wear limit, so I put heavy duty
springs in it. That fixed the problem. Problem is that the clutch lever
was so hard to pull, my arm was sore by the end of the day.

I replaced the engine with one from a 1984 VT500C.
It's having the same problem.
I don't want the heavier springs if I can help it.
Is it possible that the springs are just old and weak.
Will replacing with new standard springs fix it?

I drive it every day, so I'm not wanting to take it apart and measure
the discs before I order parts. It's a big hassle and will be all
over the garage floor while I wait for parts. I'm far to lazy to
disassemble
the original engine to get the heavy-duty springs.

I'm assuming that it's a bad idea to use two regular and two
heavy duty springs. Opinions on that?

Is there any magic way to guesstimate the disc thickness from the
position of the actuator lever?
The 83 engine with the heavy springs has about 90,000 miles on it.
The 84 engine has about 60,000 miles.
If I look at the arc the actuator lever moves through from the back
stop until it engages the clutch mechanism, the older engine has about
twice the angle as the newer one. It would be easy to conclude that
the discs in the 84 engine are thicker, but I realize there are a lot
of tolerances involved.

I'd also like recommendations on where to buy reasonable quality
clutch springs and discs for cheap. I looked at several online shops
and they have cheap prices on similar clutch parts, but no
listing for mine.

It's old and I don't want to pour a lot of money into it.
I'm old and nearing the end of my motorcycle days.
I'd just like to add a little more duct tape and keep it
running a while longer.

My strategy depends on whether clutch springs normally get weaker
over 30 years and I might get by just replacing the springs with
standard ones?
Futility Man
2017-07-01 01:28:07 UTC
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Post by mike
My strategy depends on whether clutch springs normally get weaker
over 30 years and I might get by just replacing the springs with
standard ones?
I stopped a clutch from slipping on a V65 Magna (very similar clutch setup,
just bigger). All the plate measurements were within tolerance, but it would
slip at full power. I removed the clutch plates and media blasted all the
smooth metal plates to roughen the surface. Bingo, new clutch. It lasted until
I sold the bike a year later and I was not kind to it.

--
Futility Man
The Older Gentleman
2017-07-02 08:20:53 UTC
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Post by mike
The clutch slips at full throttle. I'm using 20W50 oil to keep the
valve train noise down, and that doesn't help.
The VT500 clutch was basically the same - if I remember correctly - as
the 250/400 Super Dream unit, and was always prone to early wear and
slipping because of the extra power. And, as you say, the heavier grade
oil will only make it worse.

New friction plates and springs should fix it. Don't fuck about trying
to do it on the cheap - just buy new. It's not that costly anyway.

I can't believe that you are unable to find clutch parts for this bike.
Improve your Google-fu.
--
Kawasaki Ninja H2 Honda CB400 Four CD200 CG125
BMW R60/6 & R100RS 660 Tenere Street Triple
More garages needed....
neil underscore murray at fastmail dot fm
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