Clutch going from 75% enagaged to 0% engaged instantly

[maxh]

I recently got a used YZ250. First time out it ran for about 15 miles and then the clutch stopped engaging entirely. It had seemed to have been slipping during the day, but was a fun ride. Seemed odd that it just stopped dead.

I put in new fibers, steels, and springs and took it back out. It ran 10 miles and then we took a break and changed the oil (hoping to get things cleaner in there b/c of recent clutch issues. After about 15 minutes we went to head back out but my bike once again had 0% engage in the clutch. I could push it forward in gear with no resistance and when started I could let out the clutch and no movement at all.

Why would a bike go from 75% to 0% instantly?

I double checked that it was a 2000 and that the fibers/steels were the right size. I then removed the clutch cable entirely so it wouldn't be a factor and with the new steels, springs, fibers I was still able to turn the pressure plate w/o effort. There seems to be extra gap in there, but if that is the case, then why would it run for an hour pretty well and die instantly? If there was extra room it seems it would not run at all.

I'm perplexed. What would cause a clutch to stop engaging so suddenly? I would love any thoughts and suggestions of things I can test out or look into. I'd rather not start replacing expensive parts simply because I am currently stumped.

 

[wirefryer#85]

Get ahold of a schematic diagram and go over it, it almost sounds like something is missing. Odd that it hooks up for awhile then slips when its hot.

 

[sick 96 250]

not sure how the yamaha dirt bikes are but i know sometimes there are arrows on the pressure plate that have to match up with the inner basket, if its not set in correctly it can cause your clutch to act all weird

 

[xcracer72]

install an extra metal plate in the middle of the stack next to another metal plate. this will make up some gap. temporary fix but i have had a bit of success with it