Turned down stock M900 flywheel:
On a kitchen scale it weighted in at 930 g, on a fishermans scale 0.95 kg, maybe symptomatic for that sport .... we´ve had a flywheel like this one on out SSie900 rain day track bike with no problem.
The steel in the flywheel is quite hard, and I would not do it if I did not have the sintered-steel machineing tips, don´t know what they´re called in english.
In about 2009 I started a project for a St2-based track day bike, but due to family and work obligations and some other things that turned up, I never got beyond the engine:
Kämna 45/39 heads, Pistal hicomp pistons, Autoverdi rods, balanced and lightened crank, lightest Kämna alu flywheel, new crankcases (with piston cooling jets), close-ratio gearbox from a Monster900 / 2002. The motor has been standing in my garage since 20012 or so, and in the meantime everybody running 2V bikes have turned up with 1100 motors.Powerwise, the 1100´s more or less take off where this engine might end, I´d be happy with 98-100 horses in this one.
The motor in the rain bike now has something like 80k km on it, has started to sound very rough, so time permitting I´ll put this motor in it, just to see how it works. We´ll see ...
For track days, I´ve given in, an now have a 749R with a HYM1100 motor in it, Stock, so far,, and otherwise work in progress ...