Hi everyone first post here

Ok I have a 99 sportsman 500 that acted up one day with the backfiring and wouldn't go over 15mph then we put new plug in it worked fine took it out couple days later in the snow here in MN and started to act up again did the new plug deal but it still backfires at anything past half throttle this machine has a k&n cone filter and the bag that goes around it which now has a hole where it was backfiring through. Oh went through the carb everything was good but what does anyone think bout the feul pump not putting out enough? Going to pick up a replacement jet anyways and maybe a rebuild for th fuel pump too.

thanx

 

Had the valve lash checked lately?

 

check the throttle control , take the cap fff the throttle and adjust the slack so there is just a little bit, Ive seen this happen before.

 

make sure you dont water in your gas as well. it will back fire sometimes if its running too lean