lightening rotational mass is all well and good, but removing a harmonic damper is a bad idea. I've seen engines knock out main bearings with the non damped resonance you get. Also if you look at balancing data, you will always find the flywheel end will have a greater degree of unbalance. all you do by lightening the pulley end is widen the error, end to end. No need, no benefit, no bloody point