Torsional vibration (harmonics) dampening and reducing the whip (actual bending and reflexing) of the crank are two different things.
The extra weight is the only thing that would affect the whip problem by acting as a stronger counter balance. However in that case then the opposite can be said that a lighter flywheel would actually make the problem worse.
This is why I state the 3L crank and it's already heavier integral counterweights would be a better deterent.
I never weighed the 3L crank but was told the difference is fairly significant. Weight that is integral to the crankshaft itself plays an exponentially greater factor on whip, vibration, and harmonics.
From a layman's terms my 3L with the stock damper is smoother then my 2.5L with the DMD was. Even with just a 9lb flywheel out back.
