Wossner forged piston kit designed for Yamaha YFM660R Raptor and YFM660F Grizzly models, featuring a 100mm bore and 99.93mm size for high compression performance. Manufactured in Germany, this piston is engineered to enhance heat transfer, ensuring uniform expansion and even thrust load distribution. The elliptical design prevents localized pressure and piston collapse, making it ideal for high-performance applications.

Features

• High-strength forged piston for durability


• Optimized heat transfer for improved combustion efficiency


• Elliptical design to ensure uniform expansion and reduced localized pressure


• High compression ratio for enhanced engine performance


• Manufactured in Germany

Specifications

• Bore: 100mm


• Size: 99.93mm


• Part Number: 8577DA


• Compression Ratio: OEM


• OEM Compression Ratio: 19.20:1


• Lock Part Number: CW22


• Ring Set Part Number: 1000XSY


• Rod Part Numbers: P4037 (2001) P4038 (2002-2005)


• Displacement: 660 cm³


• Stroke: 84.00mm


• Clearance: 0.07mm


• Dome Volume: +18.20 cm³


• Compression Height: 27.00mm


• Theoretical Weight: Not specified

Cross-Reference OEM Part Numbers

• 3YF-11631-00-X0


• 44737M10000

Vehicle Fitments

• Yamaha YFM660R Raptor (2001-2009)


• Yamaha YFM660F Grizzly (2001-2009)