PISTON KIT 01-04 YFM660 101.00, WOSSNER 8507D100 YAMAHA ATV

This Wossner Piston Kit features a 101mm bore (oversize +1.00) and is specifically designed for Yamaha XTZ660 and select ATV models. Engineered with a forged construction for maximum strength and longevity, this piston delivers precise thermal performance and uniform thrust load distribution. Its elliptical design and superior metallurgy make it ideal for high-performance and heavy-duty applications. Made in Germany.

Features

• Forged design ensures enhanced durability and strength

• Optimised heat transfer from the combustion chamber to cylinder walls

• Elliptical profile distributes load evenly and reduces risk of piston collapse

• Manufactured in Germany

Specifications

• Bore: 101.00 mm

• Measured Bore: 100.93 mm

• Clearance: 0.07 mm

• Compression Ratio: OEM

• OEM Compression Ratio: 9.20:1

• Dome Volume: -0.30 cm³

• Compression Height: 27.00 mm

• Display: 660 cm³

• Hub Stroke: 84.00 mm

• Part No.: 56-W8507+100.WO

• Piston Kit Model: 8507D100 (+1.00)

Vehicle Fitments

• Yamaha XTZ660 Tenere 1991–1998

• Yamaha XTZ660 Raptor 1991–1998

• Yamaha YFM660R Raptor 2001–2009

• Yamaha YFM660F Grizzly 2001–2009