[MikeK]

Originally Posted by BRENT in 10-uh-C

. . . He wants one that works, ...yours does not!

True dat!


The cause:



Below, graphed, you can see that the severity of rotational deviation
is greater as you move forward from the flywheel mass.
This is why a damper is placed at the FRONT of the crank:

Anyone who claims they can prevent this by adding dampening
at the flywheel end is a good snake-oil salesman.

Anyone who claims they can feel smoother running in the seat of their pants
from addition of any "harmonic" device is simply describing improved
primary balance after rebuild. The harmonic torsional flex of the crank
cannot be felt while driving. It is not an 'out-of-balance' condition.