I have a recently developed problem with my 2006 Yamaha Bruin 350.

I start the engine with the gearshift in neutral, but after starting, when I try to shift into Forward, there is either a grinding sound followed by a severe jerk, or just a severe jerk as the transmission engages. This occurs even with the engine at low rpm and it hasn't started happening until just recently.

Any ideas as to the problem and how to fix it???

 

Bruins have a centrifugal clutch so it seems like this is stuck in the engaged position, it is just possible the belt pulley sheaves are sticking and giving too high a gear when you set off, but I would have thought the belt wouldn't move until the centrifugal clutch engaged anyway. Take the belt cover off and check if the front pulley is free to rotate by hand with the gearbox in neutral.

 

Are you sure it isn't idiling a little fast especially if the choke is still on yet.