Okay first we have a 2000 yamaha blaster .30 over with newer exaust. We were riding one day and once you would get into the higher gears it would miss fire... Then another day we were riding it would miss fire when we he was down shifting. and at one point it the atv stalled and then he started it back up and it would move forward and it was like stuck and it would not shift into any other gears and after about 10 mins we got it and that hasnt happend again so far any ideas would be great..