Clutch weirdness

[Y0ssarian]

I had a weird problem recently and I wanted to see what thoughts people had about it. 2008 Conc' with 57,000 rootin', tootin' miles.


Problem: About a week ago I noticed that as I let the clutch out the amount of effort needed to keep it squeezed would drop and recover from about 80-90% lever travel. It's a very weird feeling to have the lever "do something" while you're squeezing it. When I headed up an on-ramp the engine "spun up" in fifth gear; the clutch was slipping. When I pulled in the lever it was obvious there was no "free play"; the lever was slammed outward. The thing is:
- it was slipping pretty badly, and I hadn't noted any slippage before
- I've been on two forums specific to this bike for years and I don't recall anyone ever changing their clutch
- I'm usually really gentle on my clutches
So I limped home to think about it. I figured the problem was either "external" (in the "actuation" part of the clutch system; the master cylinder/hose/slave cylinder) or "internal" (the clutch stack or part of it was moving). Since the problem was something I could feel through the lever, I knew I was way behind on changing the fluid (maybe 3 or 4 years) and I always use a fluid with high boiling point (which usually means lower lubricity) I figured the next logical step was to flush the system. I got some good fluid and flushed the clutch as well as both brake systems and went for a test ride.
The problem was still there. The first thing I did was a few roll-ons in fourth, fifth and sixth to test the clutch and got no slippage. I did a loop of maybe 20 miles, and by the time I got most of the way home, it was completely normal. I kept riding and after a first-gear blast it returned, but much less pronounced. After two or three more pulls on the clutch it went back to normal. On subsequent "blasts" everything was normal.
So as it sits I think I'm ok. I think the problem was a sticking slave cylinder and that fresh fluid acts as a much better lubricant. The only thing I can't explain is why it came back to a degree after "spirited acceleration". If I have any problems with it in the future I think the correct procedure is to replace the slave cylinder.

[Daytona_Mike]

I would be doing a master kit first. What your describing to me sounds like a master cylinder issue.   Slaves do not normally do what your saying but the master sure can.  No free play is a sure sign the small bypass  orifice in the master piston is blocked or partially blocked. The master will not release pressure and then  it causes the clutch to slip.

[Freddy]

Checking the star springs is fairly easy.  I'd do that.

[Boomer]

That "pulse" in the clutch lever as you let it out is almost always caused by busted star-springs.
The Back Torque Limiter (or slipper clutch) is momentarily engaging and that feels like something pulled the clutch in for you, since that is what it does.
Common problem on the C10 and other 80's/90's Kawasakis.

[VirginiaJim]

I don't think that we've seen that many with star spring issues but the bikes are getting on in years...

[MAN OF BLUES]

C14 clutch issues, are pretty much hidden.. just saying, since introduction on '07, there is a very limited database on them,... I tried, but hell, it's almost impossible to document. spring issues, even tho they have "added" stars and an aux multi spring setup to the slipper, are and could b a cause, but more likely it is a hydraulic issue..