Running on 3 cylinders


Hi, hoping someone can help with the issue I’m currently having. I have a 1981 Suzuki GS650E. Engine was running fine with good compression prior to taking the engine apart to fix a transmission problem.

Now that the engine is back together I can’t seem to fix the issue I’m having with cylinder 4. All other exhaust pipes will run hot except 4 which runs cold.

I completed the following with no success:
- check coil plug on 4 and it sparks. Tried swapping coils around and cutting the coil wire and it’s still cold.
- throughly cleaned the carbs and check float multiple times. No fix
- checked compression on 4 and it’s ~125psi

The spark plug on 4 is wet. Seems to be oil as it’s going through number 4 exhaust making it smoke white. Exhaust is now backfiring on idle and usually have to use choke every time I start the bike

any help will be much appreciated


Tried running again today. When removing the spark plug there is white smoke coming from the spark plug hole. Also, when the bike is running and I try to adjust the fuel mixture on carb 4 it makes no change to the idle speed both turning all the way in and all the way out- removing the screw keeps the bike running

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