My Problem is this:
I have a set of 308cc Polini barrels and heads.
I managed to source piston kits for these, but they are actually NSR125 big bore kits.
So, the gudgeon pins are 16mm. Is there any way that I'll be able to use this on the 250 bottom end?
Option I have at this stage looks like I have to get 2 NSR125 rod kits and then get a set of big end bearings to fit the crank (25/31 x 16).
Unless one of the MC18 cranks that I have has a 24mm big end crank pin.
I was hoping to use the MC21 crank though.

Neal: Is there anywhere(in South Africa) I can get the center main bearing for the MC21 crank?
TBR engineering replaced the outer mains, but he couldn't source the center one.