I've got a new 200cc atv that backfires during deceleration after a hard aceleration. It shounds like a gunshot. I've check the exhaust mount to the engine and I think it isn't leaking. I've checked the carb seals on the engine side and they look good. I haven't tried adjusting the air screw on the carb yet. Any other ideas what to check?

thanks,
Brendin

 

exhaust mount to the engine and I think it isn't leaking

thats your problem. i would bet on it.

 

sounds like your running lean that will make it backfire after hard acc. check your spark plug and make sure it is not white. should be light brown or tan. If your not sure do a plug chop. wot for 15 seconds kill motor drop throttle pull clutch if you have one. pull the plug if its white your lean on main jet. You can also raise your needle all the way up by lowering clip. If you think your intake to engine is leaking try propane around the seals. If its leaking it will rev up with the propane