2009 sportsman 400. Has me stumped. You can get it to fire but runs pretty rough, smokes a little and won’t idle. Checked valves, replaced head-gasket, cleaned carb, new plug, checked the timing 3 times. For life of me I can’t figure out the issue. Unfortunately I can’t find much info online with people with the same issues?? And suggestions ?

 

What is the compression? What color is the spark and will it jump a 3/16 gap? Did you use a good carb rebuild kit or just a clean and reuse old parts and gaskets?

 

Compression was 80+ pounds. Cleaned the carb, it did have a main jet was a little clogged up but everything else seemed to be fine so we cleaned it up and put it back on. I may get a new rebuild kit for it yet. As far as the spark color and gap goes I’ll have to look into that and get back with you.

 

Compression is pretty low, needs to be over 100. Add a squirt of oil in the cyl and check again, if it comes up you have a worn cyl, if it stays low, you have bad valves or out of time.

 

Service manual states 50-90 on compression. Also the four wheeler only has 300 miles on it.

 

Ok....that is a low one, most are 110 plus.....is this a 2 stroke? If you rebuild the carb, get a good kit for the factory carb and rebuild with new gaskets. It only takes a teeny tiney spec of dirt to cause problems