The mc16 is nearest to an NF5 RS and (if you've got the right year bits) the only one you're going to be able to come near to just bolting togeather, the F3 mc16 manual just reads "fit RS crank", "fit RS pistons", "fit RS gearbox", "fit RS electrics" etc.

By the time we get to the '18 nothing just fits though the crank is still RS style, MC21 and MC28 are not.

But Matt's right, it can all be presuaded to go in, after all an RD350 motor fits in an mc21 if you try hard enough.

There is a wicked F250 (uk club proddy race series) bike there to be built as RS cases are banned but RS internals, barrels and electrics are not, nor is RS running gear. An RS with an NSR frame and crankcase would be legal though possibly not in the spirit of things.
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