PISTON KIT YFM400FW 00-06, FORGED WOSSNER 8901DA 5GH-11631-00-00

This Wossner piston kit features a standard 92.00mm bore with a measured diameter of 84.42mm, engineered for Yamaha YFM400FW Kodiak (2000–2006) and YFM4 Grizzly 400 (2007–2008) models. Built for durability and thermal efficiency, this forged piston is optimised for four-stroke engine performance in utility ATV applications.

Features

• Forged piston construction for superior strength and reliability

• Advanced heat transfer design from combustion chamber to cylinder walls

• Elliptical profile promotes uniform bearing surface under thermal expansion

• Even thrust load distribution reduces localised stress and prevents piston collapse

• Manufactured in Germany

Specifications

• Bore: 92.00mm

• Diameter: 84.42mm

• Display: 400 cm³

• Stroke: 70.50 mm

• Clearance: 0.08 mm

• Compression Ratio (Wossner): 8.50:1

• Compression Ratio (OEM): 10.50:1

• Dome Volume: -2.90 cm³

• Compression Height: 26.90 mm

• Clips P/N: CW20

• Pin P/N: WP052

• Ring Set P/N: 845XSY

Cross-Reference OEM Part Numbers

• Part No. 56-W9924.00A.WO

• Wossner Piston 8901DA

• 5GH-11631-00-00

• 40076M08450

Vehicle Fitments

• Yamaha YFM400FW Kodiak 2000–2006

• Yamaha YFM4 Grizzly 400 2007–2008