Wiseco PK1063 Yamaha YFM660 11:1 CR 102mm Piston Top End Kit

The Wiseco PK1063 is a complete top-end piston kit designed for the Yamaha YFM660 engine, featuring a performance 11:1 compression ratio and a 102.0mm (4.015") bore diameter (Wiseco piston code 4811M). This kit provides everything needed for an oversize bore rebuild or top-end refresh, delivering the precision fit and durability Wiseco is known for in the powersports industry.

Wiseco pistons are forged from aerospace-grade aluminum alloy, offering superior strength and heat resistance compared to cast pistons. The forging process produces a denser, tighter grain structure that withstands the demands of high-performance and off-road riding.

Kit Includes:

• Forged aluminum piston (102.0mm / 4811M bore)
• Piston rings
• Wrist pin (piston pin)
• Circlips (wrist pin retaining clips)
• Top-end gasket set

Key Specifications:

• Manufacturer Part Number: PK1063
• Wiseco Piston Code: 4811M
• Bore Size: 102.0mm (4.015")
• Compression Ratio: 11:1
• Application: Yamaha YFM660

Wiseco's forged piston kits are manufactured in the USA and are a trusted choice for ATV engine rebuilds. The 11:1 compression ratio provides a strong power increase over stock, making this kit ideal for performance builds and oversize bore applications requiring reliable, race-proven components.