Not entirely sure where you're going with that question!
Based on the info you provided, you have MC28 engine cases in an MC21 chassis (well, frame at least). There's no difference between the later MC21 cases and the MC28 cases. The MC21 GPS (gear position sensor) will have been fitted in place of the MC28 neutral switch to enable the PGM-III to operate correctly.
Running an MC28 with MC21 clocks is a completely different question, and an entirely different kettle of fish! _________________ Andy.
NSR-WORLD.COM
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Like maybe of us here, I love NSRs and was lucky enough to be able to purchase one.
I have purchased a NSR250 MC21 and it's in need of being restored. She's not running as she is half assembled and quite tired.
I started looking up MC21 parts and in the process noticed that the engine number falls into the range of a MC28. This surprised me since the bike was sold to me as a MC21. More importantly, the frame, fuel tank and instrument clocks are indeed all MC21 parts! I was thinking perhaps the engine number is incorrect, or perhaps it's a mutant bike.
This leads me on to believe that the next step for me on the journey of restoring this motorcycle is to truly identify what engine I have so that I can follow the corresponding parts and info on rebuilding/tuning.
So I have started this thread to look for other factors to identify if I have a MC21 or MC28, besides from the engine number itself....
I hope this helps clarity where I'm trying to go with this thread!
Again, based on the information, it's almost certainly just an MC21 (bike) with an MC28 bottom-end.
There is no difference between the two bottom-ends, other than slightly different gearing in the transmission [if the complete motor was fitted] and the aforementioned GPS/neutral switches.
If you are going to try and convert what you have to an MC28, based purely on the engine number, you are in for an extremely expensive, and not particularly straightforward rebuild! _________________ Andy.
NSR-WORLD.COM
Please keep all responses to Forum posts on the Forum so that others may benefit.
Please DO NOT PM me for technical advice. My time is precious, and you will probably receive a faster response on the Forum anyway.
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