My 440EX has had some pretty hard hours put on it. It was raced before I got it couple of years ago. Since then I have put the 440 piston in it. Today I noticed that I am getting a pretty bad vibration from the engine starting about mid throttle and on up. While riding I can feel it vibrating though the foot pegs. I am prolly gona tear it down completely and go through it, but was wondering if anyone had any ideas about what I should be looking for. I know I will replace all the crank bearings and seals and maybe this is where its coming from. But if someone has seen this before and found the problem, I sure would like to know.
Thanks,
REX

 

Mine vibrates like a mother fo and I can feel it through the throttle and handlebars. M thumb and hand actually hurt after a short ride down the road going fast. I'm trying to find the source of the problem as well.

 

That motor is well know to be a vibrator.