Total Motorcycle Community Forums

I bought this bike about three weeks ago and it ran great for the first 250 miles. Now it is fouling plugs on just the right cylinder. THey are brand new NGk plugs, correct heat number and all. It only fouls it on the right cylinder. I had cleaned the carbs when I first bought it and didn't bother installing an in-line fuel filter. Also the air filter appears to be clean. This bike runs off a single coil and looks to be getting a nice spark. The plug lead is not cracked or deteriorated. So what could be cousing the plug to foul on just one cylinder?

Thanks,
Nate

Difficult one to trace down. Try swapping the plugs around and see if it is firing ok on the right cylinder, and not on the other where you put the plug. This would point to a defective plug. This can happen even on new plugs, especially if it has been dropped on the floor or anything. Assuming it still fouls up the right cylinder, then you need to start looking at the HT lead or the carb.

Hope this helps.
S

Replace your plug cap & wire.