I've got a 99 kdx 220 with mild porting, Bored carb, cut box and an FMF exhaust. I'm experiencing some clutch slippage and want to replace. I ride the woods and roost alittle. Also does anyone recommend any change in the clutch springs?
Call Jeff Fredette at Fredette Racing. He has a great setup: a set of stronger springs and some replacement XR250 friction disks. The disks are same thickness as the stock KDX disks, but have more surface area for a "wider" engagement. They fit perfectly.
I did it this spring and the result has been great, the clutch is very robust, but the pull is not noticeably harder that stock. The feel is different, in that the engagement "window" is narrower - but I like it that way.
I followed your advice and got the new wider contact plates and stronger springs from Jeff. But when i took the old ones out there was a large conical spring-washer on the outside stack and a almost flat shim about the same thickness as the clutch plate between the inside diameter of the plate and the center clutch hub these two parts don't seem to fit with the wider plates. Do i need to install and origional on each end of the stack? or what.
Those two things are the "coned disc spring" and it's seat. My theory is that they are as useless as you-know-what on a bull. Seriously, their function appears to be to soften the engagement feel (e.g to make it less abrupt) - not exactly a huge KDX problem, IMHO. After asking around and studying the situation, I left mine out and have not regretted it. The clutch feel is fine and it's one less thing to break. The other thing the shop manual tells you to do is to offset the last friction plate in the special little notch the basket has for it. This did not seem like a good idea either and I installed the last one to line up with the rest. I'm happy with the way my clutch has been working this season.