QuestionI have experienced backfiring for a while when I start it and when I down shift. Now it doesn't even start. Someone has told me to check the timing. I tried the carb cleaner in the gas tank. Has new plugs and air filter. Do I need to put in a new fuel filter? It has been a while. Your expertise is greatly appreciated. I have been riding only 3 years, but really want to do some work myself.
AnswerHi Barbara,
Chances are good that the backfiring is only a product of a "rich" condition Which means a few things and reasons for them.
1 could be there are holes in the mufflers (common for that year shadow) producing insufficient back pressure in the engine.
2 could be the carbs have been rejetted for aftermarket exaust, and not RE-jetted correctly also causing a "rich" condition.
Rich meaning too much fuel in the system for the engine to burn...It usually will make its way to the mufflers in a "vapor" state, and eventually when A spark reaches it, you will experience the "popping/ backfiring" effect you made mention of.
Try replacing the spark plugs with a hotter plug, your local parts store should be able to tell you what a hotter plug is geven you give them one of yours.
Your best bet is to read your spark plug.
Black and sooty = rich, un-burnt fuel
Tan = Good
White = lean (not enough fuel)
Other than the NO START condition, the hotter plug should help burn off the excess fuel it sounds like you have, as far as the Backfiring sounds, as long as the bike is running, it needs not be a concern....as long as its running, it wont dammage anything...The hotter plug should cure it though...
Go from there...
Hope this helps!!
~Mark D. Panka
