Wiseco 4828M03900 39.00mm 11:1 High Compression Piston Kit for Motorcycle Performance Upgrade - Perfect for Racing, Off-Road & Engine Rebuilds

Bore: 38.96mm Compression: 11:1 Compression Sizing: Standard BoreSPECIFICATIONS. Displacement: 49.5cc. Bore - Standard: 39.00mm. Bore - Actual: 39.00mm. Bore - Oversize: STD. Stroke: 41.40mm. Compression Ratio - Actual: 11:1. ITEM CONTENTS. 3900XZ - 39.00 mm Ring Set .8 X .8 X 2.0mm. CW13 - ROUND WIRE PIN LOCKS 13MM (PAIR). S671 - PistonPin 13 x 29.75mm NonChromed TW All Wiseco Pistons are forged from high silicon, low expansion aluminum which offers superior strength, reduced weight, improved heat transfer, and longer life. Diamond turned finish from one of the many CNC computer controlled turning centers guarantees you a perfect finish with no size variation. Wiseco pistons can be installed in any of todays cylinder bore compositions. Wisecos state-of-the-art computerized manufacturing facility is dedicated to supplying both the high-perfomance racer and recreational enthusiast with the finest forged piston available in todays market place.1982-1987 fits HON Z50R