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hey guys i have a 79 suzuki gs 550 and it is backfireing bad. I start it and it will idle for about thirty seconds then backfire. It is only happening from the right exhaust. the bike was sitting for about 8 months and i did take apart and clean the carbs twice in that time. Not sure if it could have anything to do with my fuel petcock cause that does leak a bit through the face plate, and the other day i was looking over the bike after having it sit for a while and one of the carbs on the side of the backfire problem was overflowing with a bit of gas.... also the air box and carbs are not perfectly together....not sure if this would cause the problem on both sides though...thanks for any help and suggestions
 

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Well fix what you know to be an issue first and go from there. You obviously have to fix the leaking gas and gap between the carbs and the air box. Address those issues and see if the problem persists as much.

Does the bike backfire through the exhaust or the carbs? Backfiring is a result of a lean condition in which incomplete combustion can lead to unburnt fuel igniting in the exhaust (which by the way is made hotter by the lean condition).

I would say you can idle your motor for a few minutes and then check your spark plugs and see what they look like. If they are dark black, the air to fuel mixture at idle is too rich. If they are white, you are lean. If they are a light brown, that is a good mixture. If the bike was fine before you stored it, I would be stumped as to what is causing a lean condition all of the sudden - other than the carbs still being gunked up and having this condition restrict fuel delivery.

If you gas it, does the backfiring get worse or smooth out?


EDIT: I re-read your post and must have missed the line about the carb overflowing. This is usually due to a worn out needle, or a needle that is gunked up. This will cause the fuel bowl to overflow. I suspect because it was sitting that the needle is gunked up. If the above doesn't work, get back in the floats and carefully clean the needles again.
 

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oil coming out tailpipe after backfire-loss of power

new to this. my suzuki DR650 backfired and lost power while i was flying down the interstate and now it won't run and oil is spritsing out the tailpipe when i do get it started. please help
 

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I had a 2008 650 Vstar custom that would do this after I put an aftermarket exhaust on it. The dealership did not jet it properly, and when going from a high RPM to letting off the throttle, my bike would backfire and die. My brother had an issue like this on his harley. It had something to do with the camshaft I believe. He needed a new head. Ill take that as being worst case scenario.
 
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