a few yrs back i had 2 steel hubs made up that sit behind
the disc rotors,basically like the drum off a drum brake.still wheelied.
a mate got a brick made up for his gen2,modelled off the gen1
brick i had but reshaped to suit a gen2,from memory
it was 6.3kg.i gave up on ballast a while back and just
learnt to ride better and pull ignition timing in first gear,that way the power returns
when u need it.