Hey my son has a 1998/1999 Yamaha Bear Tracker 250/300. The other day it started making a terrible noise when put into gear and will not drive. It cranks good and idles fine but starts the noise when gear is changed out of neutral. I appreciate any information for it is better than my novice knowledgr

 

If you are lucky, something in the rear axle may have worn out or broken. If you are unlucky it could be in the gearbox. Not sure if you can see the crownwheel with the diff filler plug removed, if you can, check it goes round with the axle shaft, as the splines can wear out. If that is OK, you may be able to feel the UJ through the rubber boot between the gearbox and swinging arm. Engine off, in first gear, roll the bike backwards and forwards feeling this UJ, if it is turning your problem is either clutches or gearbox. If it isn't, the diff or a UJ has broken.