I've got a brandnew hayabusa sprag clutch and billet assembly from Extreme Engines. These are the best you can get!

It stops the problems of starter mounts cracking, stripping starter teeth, also it allows backwards rotation ie if you spin.

All the above are the weak links with a Hayabusa engine

Link here.. http://extremeengines.com/cgi-bin/trolleyed_public.cgi?action=showprod_EXT10002

they cost £335+vat

I'll sell mine for £300 including recorded post(uk)

Also a 2001 onwards loom/ecu brought as a spare £100 posted