2006-2012 Honda TRX90 TRX90EX/X Service Manual, Page 176Get this manual
CRANKCASEITRANSMISSIONCRANKSHAFT
TROUBLESHOOTING
Hard to shift Incorrect clutch adjustment Bent shift fork Bent shift fork claw Damaged shift drum cam grooves Incorrect engine oil weight Transmission jumps out of gear Wo-'n gear dogs or slots Worn or bent sh ift fork Broken shift drum stopper arm Crankshaft noise Worn crankshaft big end bearing Worn crankshaft journal bearing