hey i was wondering if anybody could help me. about a week ago my bike started to backfire. i thought it was maybe bad gas so i drained the whole tank and refueled. when i started it it ran fine for about 20 minutes then it just died i could not get it started. so i changed the plugs. they were fouled, they needed to be changed. i got the bike started and it does not want to stay running i messed with the idle and i can get it to stay running for a little while. but the bike runs like crap still, does any one have any ideas what could be causeing the problem. i also that it might be from my brother he decieded to dump a full bottle of fuel injector cleaner a while back when i found out i drained that fuel because i did not want anything to happen to the bike. but that was like 4 weeks ago so if any one has any ideas please help me this is my only transportation, the bike is a 2004 cbr 600rr stock all i have done to it is 1 touth down front sprocket and a yosh slip on.

 

A backfire can be caused by several things, but is usually a spark at the wrong time. On our four-cylinder bikes, one cylinder is firing on the exhaust stroke. If there is unburned gas (running rich), it will explode out the exhaust (backfire). You say the plugs were "shot". That is your clue to what's wrong. Dry plugs that are black with carbon, or wet black, or white, or flecks of metal on the plugs? What did they look like.

 

Sounds a lot like you jumped timing -- although the bike seems to new for that. Could also be a sensor that's gone south -- intake air pressure or throttle position sensor can cause the bike to run like crap. It's almost impossible to diagnose over the net -- you just have to eliminate stuff til you find out what it is. Good luck.

 

slowpoke the plugs were really wet black

 

running rich
take it to a shop

 

running rich can cause.....fouled plugs, bad gas mileage, lower hp. however it won't actually damage anything
check your sensor in the air box filter
If the O2 sensors are just left unplugged, the ECU reverts back to a super rich failsafe map.

 

You guys got O2 sensors in 600RR's? Must be a CA specific thang cause they didn't have 'em here last time I checked.

 

hey dont worry mine aint running at all lol damn thing wont start still[&:]