The NSR250 flywheel sounds and feels like it is heavy to me and could do with lightening. TYGA sell a 20% lighter flywheel, though it is out of stock, however I'd probably just modify the one that I have on the bike. Who has had it done and what was the result? I've tried searching for info, but it's sparse.
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MC21 Honda NSR250. TYGA 300 conversion.

Hi , search under my 300 posts and you will get answers , I just posted a graph in Alzazorgs piston comparison . I have a spare one

Looks like you got 1hp over 9,000rpm. Looks worthwhile, does it feel better and rev nicer at idle?