I had PM'd Banshee. He got the Piston 'no mark' kit from Jap4 / Tyga, which is the match for his B size barrels.

But for others with A & C barrels, I would take care when ordering a 'Top End Kit', Tyga's website only lists the kit with Piston 'No Mark' and for barrel sizes A & C you will need Piston sizes B & D, according to the OEM manual.
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Rich
MC21 Track Bike / RS250 NF5 'Spencer', NX5 'Cadalora' & NXA 'Aoyama' / RS500 / Two Brothers Racing RC30