I have a 2008 yamaha raptor 350 and I always bump start it due to arrival of a starter clutch has been delayed and today I tried to start it and the wheels will turn but not the engine. Just wondering if a transmission gear has stripped out. It does make a grinding noise from that area and I can push the quad fairly easily with it in gear

 

Have you checked the chain is still on the engine sprocket? If it is and the sprocket goes round when you push the bike in gear, but the engine doesn't turn, then yes the gears have gone, or the clutch, but I wouldn't expect gear grinding noises if it was the clutch. Check that it isn't just the splines on the sprocket that have failed, but it looks like the clutch cover will have to come off and possibly a total sripdown, if it is actual gearbox parts that have failed.

 

Thank you for the info, have checked the clutch it looks fine and the shaft that the chain sprocket spin but not the motor im thinking it needs a trans