http://www.wiseco.com/Catalogs/DirtBike.aspx
While they may not have something for the NS250R, the PDF catalogues are good for cross-referencing piston and gudgeon pin sizes. That could narrow down the selection to a few pistons. You may find you need to modify the barrel if you use a different manufacturers piston, so it would make sense (if that is the case) to do both barrels so matching pistons are used.
I would hate to say all is lost though, when you see people with all kinds of old vintage 2-strokes restored and running. The NS isn't that old just yet!
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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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