Was the pressure plate indexed to the flywheel? It should have been if it was balanced.

Have you checked compression and leakdown for a weak cylinder? If you can eliminate differences in power between cylinders, the vibraiton is coming from an out of balance mechanical part. Do you have a balance sheet that shows what everything was balanced to??

chip


Preaching the Hot Rod Gospel according to the 4-stroke apostles:

Suck, Squish, Fire and Fumes