I am unable to get my 96 sportsman 400 to run, I have cleaned the carb multiple times and have a brand new plug in it, it also has fresh gas and have also has the flywheel removed to check keyway and checked fine, has spark but will not start, will backfire every once in a while while using electric starter.. any ideas?

 

Welcome! Since you have spark and have cleaned the carb I would check the compression next. If it's less than 120 psi could be time for a top end. Could be the cause of the backfiring. Check this out and get back to us. If compression is decent could be a couple other things. OPT