I have a 1992 yamaha big bear 350cc and I took it out yesterday to get across the corn field and it would drive fine and then suddenly lose power and stall. It would then start right back and drive fine a couple hundred feet and do it again. It happened about 12 times in a quarter mile. When I got back up to the road I got on the throttle and it spitted and backfired. any suggestions?

 

Is your quad equiped with an emergency brake? My 05 has one and they put a safety switch on the left brake lever adjacent to the emergency brake. This switch is meant as a safety and works like a rev limiter. Check it out

 

Check carb and gas tank vent tubes too. Could be kinked or stopped up.

 

My son's quad did something similar. I was going nuts trying to figure out why it was erratically stalling and shutting off and was hard to restart.

One night while jacking with it, I got down to ensure that I was shutting the choke off all the way and saw where the spark pug wire was touching the cylinder head and it was arcing across the wire to the head. Short term, I zip tied the plug wire away from any metal but I really need to replace the plug wire. Since then, no issues.

Check that plug wire in dark, if you see arcing then that's your problem.