I bought a non running sportsman 400 2001 it has been sitting for 3 years I needed somthing to use around the house so I figured I could get it running to use after getting a service manuel I checked compression, valve adjustment, and confirmed the timming marks line up and all checked out also changed all fluids flushed fuel tank and put new gas in tank cleaned carb out to checked for spark and didn't have any I did some checking around and found out the ingnition switch was constantly applying ground to the kill wire unplugged wire and 4wheeler started right up and idled great but when you rev up the motor it pops back throu the carb also blows the gas out toured the air filter it's almost like exhaust is comming out the carb but like I sead before all the mechanics of the motor check out is it running lean? any help would be greatly appreciated. thanks

 

Have you adjusted etc? If it is out of adjustment then it will cause it to backfire. If the exhaust lobe on the cam is worn out then it can cause this. But it would most likley run better at idle and when reved it would choke down

 

It has great compression and cam lobes are in good shape. what is the etc?

 

The etc is "electronic throttle control" It basiclly has a kill switch built in to the throttle lever so if the cable were to hang it would kill the spark when you let off. You should have no more than 1/16 inch of play in the throttle lever before it starts pulling the cable. You can adjust the cable at the juction just below the throttle lever . Pull the rubber boots back and adjust the play. Make sure you turn the handle bars to make sure you don't get it so tight that it makes the engine rev when you turn the handle bars.

 

thanks, that's also adjusted correctly

 

you can also pull the carb off put your hand up to the intake port spin the motor over and it sucks your hand right up and their is no exhaust blowing out