Rotational inertia of the pulley is *much* less than that of the flywheel because it's so much smaller. Not much point in balancing the pulley on it's own since it's so poorly located that it's centre of rotation will almost certainly be different when mounted on the crank than when mounted on the balancing machine. Difficult to balance on it's own anyway since it actually mounts on the cam belt pulley which in turn mounts on the crank.
Location of the front pulley is the thing which prevents the whole crank assembly from being balanced to the nth degree, since just unbolting it and bolting it back on can result in very measurable unbalance variations - so don't believe any BS from a balancing 'expert' telling you they can balance the whole assembly to a few gmm, 'cos it's just not repeatable. Rant over...
Oh meant to say... the damper is the rubber insert which isolates the inner section of the pulley from the outer. The standard pulley does the alternator and dry sump (utilising the otherwise redundant power steering pump drive part of the pulley), whilst the cambelt is driven via a toothed pulley which is sandwiched between the front pulley and the crank.
Another way of gearing down your alternator is to get a bigger pulley for it (and a longer belt).
Mike
Edited by - Mike Bees on 3 Feb 2005 13:49:50