Look tidy but a single ring piston. Is this for track/race bike? I've been running single ring wiseco pistons in my MC28SP and have been on the cautious side of rebuilds and have been replacing every 10-12 hours. The pistons and rings have always been to spec but with that run time, I'm getting blowby on piston wall. Bike also has NF5 porting.

Take one for the team!
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MC28SP, '16 KTM 500EXC, '16 Beta Xtrainer, '07 BMW 1200GS, '96 Ducati 900SS