If you take a look at the Online Parts Manual, you will see there are notes regarding piston matching on the crankshaft page:
A "no mark" piston is required for a "B" barrel, but please be aware these bikes are 20-30 years old now, depending on model, and can have had barrels replated (several times in some cases) and may no longer be standard sizes.
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Andy.
NSR-WORLD.COM
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