| Forged from high-silicon aluminum alloy for maximum strength and dependability.. Innovative forging design and piston skirt provide maximum horsepower and torque.. Wiseco High-Performance piston kits are priced with piston, rings, pins and circlips (unless noted otherwise).. Oversize pistons require cylinder sleeving.. SPECIFICATIONS. Displacement: 66cc. Bore - Standard: 44.50mm. Bore - Actual: 45.00mm. Bore - Oversize: 0.50mm. Stroke: 41.60mm. Note: Cylinder sleeving required. Note: Cylinder replating required. Note | Electrofusion Bore. ITEM CONTENTS. 1772CD - 45.00 mm Ring Set. CW12 - ROUND WIRE PIN LOCKS 12MM (PAIR). S595 - PistonPin 12mmx 1.417 NonChromed SW |