fritz:
i went thru this when i updated my '02 650. i started with an '06 honda f4i starter and found it didn't spin up well, and ended with a '99 yamaha r6. it seemed to turn the engine over faster. to get to where the start was reliable, i eventually modded the cam to use the '04-up auto decomp (dutch clog) because after replacing the original autodecomp, the new one only lasted 60 hrs before eating the lobe.
the starter is a mitsuba sm-14 and the only mod was to redrill the mount holes for the stock 650 bracket. the part of the yam starter that stuck out was used to mount the solenoid.
pics in the doc under engine upgrades.