I have a 1987 Yamaha Moto4 250 I got cheaply off someone I know and got it running. Pretty much everything seems sound but the clutch doesn't disengage. It can still be ridden by just putting it into neutral when wanting to stop, but it is quite annoying. Anyone one have ideas?

 

They have two clutches, a lawnmower style centrifugal, and a normal motorcycle multiplate, three if you count the one way clutch in the middle of the centrifugal, this is to keep the drive engaged on the overrun and can be put in backwards by mistake on some machines, Put the bike in gear, engine off, and roll the bike forwards, it should try to turn the engine, then roll it backwards, it should freewheel, if this is reversed, someone has fitted the one way clutch backwards, if it grabs both ways, or works correctly, a shoe spring in the centrifugal may have gone. Either way, the centrifugal clutch has to be removed for a visual check.

 

[QUOTE=dassaul;3457249]I have a 1987 Yamaha Moto4 250 I got cheaply off someone I know and got it running. Pretty much everything seems sound but the clutch doesn't disengage. It can still be ridden by just putting it into neutral when wanting to stop, but it is quite annoying. Anyone one have ideas? I have the same quad mine only does that when ive got the idle at the carb turned up too much. the Idle screw is on the left side of the quad on the carb its the knurled screw. with the quad running turn that screw back and forth to see which way is faster and slower. Your idle should be set low. it should be set slightly higher than than stall.