There are 2 types avaliable, road and race.

A stock MC21 flywheel weighs around 1102g, on the "for road use" fly wheels this is reduced by almost 10% to around 1000g. We've found this to be good for the road as there is a noticable increase in engine pick up but very little loss in torque.

The race flywheel on the other had is almost 30% lighter than the stock item. This has the magnets removed as well as the flywheel itself reduced in all areas. This can't be used on the road as, of course, it will no longer charge the batt.
_________________
If I have to take the carbs off once more...