Join Date: Oct 2005
Location: Pensacola, Florida
Re: What COULD CAUSE EXCESSIVE MOTOR VIBRATION???
I had a similar problem, and it turned out to be the rubber diaphragm that is under the cover on the outside of each carb (two screws). I forget what it is called, but it controls the fuel mix when decelerating.
Anyway, mine for the front cylinder had a bunch of holes in it so it was dumping fuel into the front cylinder like it was choked. It's easy to check this, as you don't have to remove the carb . . . just the two screws. There is a spring in there also, and a very small "O"-ring so be careful! Also, you might want to take a look at the spark plugs. My front one showed a lot of carbon from the rich mixture. The fuel economy was also bad, about 31 mpg. After fixing it I now average about 50 mpg and the bike runs great.