Grabbing Clutch

1977 KZ900 with an 1170 kit built by Perry Fink of Ohio, with a clutch By Fink Racing. Has been sitting for about 5 years, the engine runs strong but I'm having a problem with the clutch letting go when the engine warms up. When it is cold shifts fine, nuetral is easy to find all is well. Drive a few blocks and when it gets warm it's whoa boy. Pull in the clutch and it's still hoked up and pulling forward and the warmer it gets the more it pulls. What could be the problem here.

In my particular case (750 twin) it was a bad needle bearing in the clutch basket that caused the thrust washer to weld itself to the clutch basket. Unlikely to be the same problem with yours though.

Get you a shop manual which has specs for the clutch springs. Sounds like the hot-rod shop that built your engine didn't change out the clutch springs. Lots of folks have installed heavy duty spring although I hate them as they make clutch pull pretty stiff. The plates are not disengaging and the ONLY function of the springs is to push the pressure plate outwards along with the clutch plates. Yours aren't so I am guessing springs are tired.

wiredgeorge wrote:

Get you a shop manual which has specs for the clutch springs. Sounds like the hot-rod shop that built your engine didn't change out the clutch springs. Lots of folks have installed heavy duty spring although I hate them as they make clutch pull pretty stiff. The plates are not disengaging and the ONLY function of the springs is to push the pressure plate outwards along with the clutch plates. Yours aren't so I am guessing springs are tired.

I would surmize that were the springs weak the clutch pack would slip.
The way I read his post he is saying that the clutch fails to properly release when warmed up.
I would believe that there would be some expansion in the pack when warmed up. This would possibly indicate that the release mechanizm is faulty or not properly adjusted

im leaning towards harrys idea here id try adjusting clutch,if that doesnt do it maybe check clutch pusher rod to see if it welded itself on.

WG kinda has that backwards, the only function of the springs is to push the pressure plate inwards and clamp the clutch plates, and I'd say yours are doing a real fine job of that

I think thermal expansion is a real good possibilty, but I don't think the problem is in the clutch pack. I'd pull the clutch basket and take a real good look at the bushing/bearing.

Post edited by: steell, at: 2006/09/19 20:47

steell wrote:

WG kinda has that backwards, the only funtion of the springs is to push the pressure plate inwards and clamp the clutch plates, and I'd say yours are doing a real fine job of that

I think thermal expansion is a real good possibilty, but I don't think the problem is in the clutch pack. I'd pull the clutch basket and take a real good look at the bushing/bearing.

it looks like hes got the drop on both us now!

My dragbike used to do that. My cause was because my oil level was too low. Was trying to run minimal oil level so as crank was not being slowed up by splashing through oil. A half quart more solved problem for me.