749 to 928 worth doing for sure. I'm not sure about this unless it were dead easy by swapping standard parts around. Do you have to buy the kit linked?
999 barrel is the same height as the 749. It's the Gudgeon pin - crown diamention that's the issue. Hence the need for the Pistal pistons. I consulted one of the designers at work. Who is ex Ilmore, Cosworth & Mercedes hpp designer. Who said no need to rebalance the crank. I replaced & re-shimmed the main bearings reducing the pre- load. And did the head work as per Brad Black report. Plus a bit of polishing and seats re cut. On the dyno there was no noticeable vibrations or nastiness. If you need any more pointers give me a shout.
Pin diameter and rod are the same. Crown height is increased to compensate. Crank pre-load I measured (granite surface plate and micron height gauge) cases mating face to bearing inner race mating face. For both sides of the cases. Added figures together. Then measured the width of the crank and shim washer with the same kit. Subtracting crank width from case width. I had .316mm of bearing pre -load. A quick chat with our mechanical design guys (with the bearing specs ) they came back with the close to the same pre-load I was thinking. So shims under the surface grinder and I reduced the pre- load to .160mm I checked for end float and radial float @ 90 *c all was good. Crank rotated nicely when cold. :Cigar:
I hate gushy 999 bike threads like this.. They make me end up with another motorcycle in the Garage! Not so many 999S 's around just right now.. 2 or 3 "R" versions, but they seem to be rising in price fairly quickly. Will keep an eye out for a decent S from now on.
