Yeah, the MC18 and MC21 motors are identical... except the cranks, the barrels, the heads, the ignition, the left crankcase, and the inlet... apart from that, it's pretty much the same!! Oh, there are some other bits too, but...

Seriously though, the motor will bolt straight in, and run perfectly fine with the different crank/barrels etc., but you will need to use the MC21 stator and flywheel, and look into what you want to do with the G.P.S. as the MC18 doesn't have one!

NOTE: Cranks are NOT interchangeable between MC16/MC18/MC21.

Andy.
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