My 2002 CBR 600 F4I is not running as smoothly as it used to. It has just recently starting backfiring. it seems to stop as it reaches temp but its never done this before. (separate issue) Also when I accelerate from a stop, there is a lag almost like the bike is going to stall. Then it just just lurches forward and accelerates like normal. I have checked all the fluids, changed the plugs, air filter, oil filter. It had a tune up less than four months ago. Need some clues as to what might be going on.


Thanks.

 

What fuel are you running? Does it have ethanol in it? I run premium no ethanol in mine

 

Maybe a fuel injector issue?