Wossner forged piston kit designed for superior strength and performance. Engineered for optimal heat transfer from the combustion chamber to cylinder walls. The elliptical design ensures uniform bearing surface under heat expansion, reducing localized pressure and distributing thrust loads evenly to prevent piston collapse. Manufactured in Germany.

Features

• Forged construction for enhanced durability


• Optimized heat transfer for improved performance


• Elliptical design prevents localized pressure and piston collapse


• Pro Series design with a two-ring configuration for enhanced sealing and longevity

Specifications

• Bore: 76.98 mm


• Piston Size: 77.02 mm


• Displacement: 249 cm³


• Stroke: 53.60 mm


• Clearance: 0.04 mm


• Wossner Compression Ratio: 12.80:1


• OEM Compression Ratio: 12.50:1


• Dome Volume: -4.80 cm³


• Compression Height: 20.50 mm

Cross-Reference OEM Part Numbers

• Lock: CW16


• Pin: WP059


• Ring Set: 770XAS


• Rod: P4006 / P4005

Vehicle Fitments

• Yamaha YZF250 (2001-2004)


• Yamaha WR250F (2001-2004)