WSM Piston Kit (639cc) - 0.25mm Oversize to 76.25mm Bore 010-810-04K Competitively priced forged pistons Coated with MOS2 for high performance and heat absorption Ported to match WSM Banshee sleeves Four piston categories from standard, big bore, 5mm long rod and big bore with 5mm long rod Piston pin is 5mm higher on long rod pistons to accommodate long rod