The Wossner 89mm Bore Piston Kit (Part No. 8702D400) is a high-performance forged piston designed for Honda TRX400EX and TRX400X models. Built for superior strength and durability, it enhances heat transfer within the combustion chamber and features an elliptical design for even load distribution, preventing piston collapse. Manufactured in Germany, this piston kit offers a compression ratio of 12.5:1 for improved engine performance.

Features

• High-strength forged piston construction


• Optimized heat transfer for better combustion efficiency


• Elliptical design for uniform bearing surface expansion


• Manufactured in Germany

Specifications

• Bore Size: 89mm


• Actual Bore Diameter: 88.94mm


• Compression Ratio: 12.5:1


• OEM Compression Ratio: 10.0:1


• Displacement: 397cc


• Stroke: 70.00mm


• Clearance: 0.06mm


• Dome Volume: +8.40cm³


• Compression Height: 26.20mm

Cross-Reference OEM Part Numbers

• Lock P/N: CW20


• Pin P/N: WP052


• Ring Set P/N: 890XSY


• Rod P/N: P4021

Vehicle Fitments

• Honda TRX400EX (1999-2008)


• Honda TRX400X (2009-2012)