Having just traveled down the well worn path of searching for a top end refresh for my MC 11 ,the 56mm. bore makes it a oddball just like a 86 KX 125,I have decided to give the wiseco KX piston a try.Same nikasil,same wristpin,I might have to conture the crown profile or trim a skirt but it looks close.Am I just reinventing the wheel or has someone already ruined a perfectly good set of cylanders and can enlighten me.....lee