Sorry if this has been asked before but I am a fairly new owner of a 1988 NSR PGM1. The crank on the engine I have needs to be replaced sometime in the future. It still runs allright but the carb needs to be adjusted from time to time to stop fouling the plugs so frequently.

My question is whether it is possible to buy a rebuilt MC21 engine and use that in the MC18. What modifications would need to be made to make that work? Would there be any cutting involved or is it just a matter of matching up the correct wires? Basically what would be a best case scenario is if you could straight bolt everything in and use the carburators and everything from the previous engine. I really have no idea what the best option would be but any advice would be much appreciated.

I won't be performing any procedures myself and will be leaving this one up to the mechanic. Although he is not an NSR expert, he is an expert in 2 stroke engines so any information about possibilities of engine swaps or compatible parts would be great. I am in Japan so it seems parts are abundant just not for the MC18.

Thanks alot for any opinions!