Hey, could someone tell me what causes backfire, I reved up my 81 honda 200 a couple of times and it backfired, was wondering if that was a sign of something else wrong with it? Just wondering,,
Thank you,

 

Probably a dirty carb idle jet.??

 

could be you need a valve adjustment my 400 outlander was doing the same and i had did a complete carb cleaning 2 befor it started doing this did a valve adjustment and now i can ride wheelies on my 4x4 and could never do that befor

 

That could be, the bike has been sitting for a while, I noticed a little rust inside the fuel tank,