I was racing this weekend at red bank and I was doing great until my quad randomly shut off. It wouldnt start back up unless i pop started it and every time i was going down a hill and pulled in the clutch and didnt hit the throttle it would just shut off and not start. As soon as i got it back to my truck and let it sit for a little it fired right up no problem and has been running great ever since? Valves are dead on to so its not that.