i am woundering i have a 1995 polaris sportsman 400 4x4 2 stroke.i had it run 2 week ago and run good i put in away to the snow came took it out and running good for 1/2hr then it stared to back fire and losting power.so i took out the old oil and gas and put in a new Uni-Filter Two-Stage Air Filter and a new BR8ES Spark Plug.stared it and it will idle good but u give it gas and it bogs down now sure what to do can any one help

 

Welcome! First thing I would do is to check compression. If compression is at least 120 or so,you might want to check the carb for stopped up jets,needle and seat problems. Backfiring and loosing power on a two stroke can be a partial seizure of the piston/rings. They can continue to idle,but will not take any throttle. Have had this happen on low compression engines also. Plus slightly leaking crank seals(especially the one behind the front clutch) can cause lean fuel/air mixture problems causing it to bog. You can also check that the throttle lever doesn't have more than 1/8" slack,but don't think that is the problem.Usually they would die if there's too much slack. OPT