So I had purchased my first atc ever and got it for an awesome price. Initially there was a problem with it not starting up at all and after trying multiple things decided to pull the head off and noticed that the previous owner had managed to completely destroy the piston. Had it bored and new piston and rings are currently installed. After installing it and putting everything back together again it seemed to run just fine, except it would seem to choke out a bit when you would punch on the gas. We thought it was surely the carb but I didn't have time after all of this to work on it so it got put off to the side for about 2 weeks. We came back to it thinking it was just something simple as cleaning out the carb and making sure all adjustments were set correctly but when we pulled it out to try adjusting the carb it wouldn't even start at this point. We can manage to get it going initially but it dies after a couple of seconds and then any attempt to start it after that seems to foul the plug so we have to clean it off and try again. We replaced the carb with a different one to see if there was something else that we over looked with the other one but still have the same problem and the second carb is a known good carb. To shorten the story up a bit we have looked over everything we can think of that could cause this problem except an electrical and timing issue. It is frustrating because the damn thing at least worked after putting it back together the first time so what could be causing this issue now? Any help is greatly appreciated.

 

well thats a long story lol so it starts than dies my atc dose the same thing my best quess would take the air filter off and try with out it and also get a brand new plug make shure in the head the ports are nice and clean check for compression or check for bad gas make shure you have the right oil weight and last if you have a rider or something that runs tie a rope to it and the other and pull it that will get the motor going always dose for me lol oh take the plug out and this might seem a little nuts but hold the spark plug with it attatched to the cord and kick it over and if the spark barrley hurts you you have week spark like me the spark should run up you arm and put you on the ground hope this helps

 

not sure man but i would say electrical if youve eliminated the possiblility of being jetted wrong. Sounds like its not fireing right and the gas/oil is fouling the plug. I'd start with messing with the timing and if that doesnt do the trick then get on ebay and buy a coil and cdi box. Good luck, long live the trikes!!!

 

my older brother has the same bike, and if you are running regular gas,it will only run for little while and cut off, try running higher octane gas and a hotter burning spark plug, hope this helps

 

I had a 250r bored about twenty years ago. I hadit bored then i purchased the piston to fit the bore, which was a total mistake. It was doing the same as your discribing. I was told by the guy at the machine shop that you have to have the piston that is going in the bike while you bore it so you don't get the bore too big. It would run till it heated up and lost compression. Maybe yours will be easier to fix.