PISTON KIT XR400 TRX400 85.50 FORGED WOSSNER 8604D050

Wössner forged piston kit with an 85.50mm bore, designed for Honda XR400R motorcycles and TRX400 series ATVs. Manufactured in Germany, this high-performance piston enhances strength, heat transfer, and durability. The elliptical design ensures uniform bearing surface distribution, reducing localized pressure and preventing piston collapse.

Features

• Forged construction for superior strength and durability
• Optimized heat transfer to cylinder walls
• Elliptical design for uniform bearing surface under heat expansion
• Increased compression ratio for improved engine performance
• Made in Germany

Specifications

• Bore: 85.50mm (85.44mm actual)
• Display: 397 cm³
• Stroke: 70.00mm
• Clearance: 0.06mm
• Wössner Compression Ratio: 11.00:1
• OEM Compression Ratio: 10.00:1
• Dome Volume: +3.20 cm³

Cross-Reference OEM Part Numbers

• Wössner Piston: 8604D050
• Lock: CW20
• Pin: WP052
• Ring Set: 855XSY
• Rod: P4021

Vehicle Fitments

• Honda XR400R (1996-2004)
• Honda TRX400EX (1999-2008)
• Honda TRX400X (2009-2012)

Majority of our listings are for a direct replacement for your original part.

Our parts are made of quality and are designed to meet or exceed the original OEM Standards.

Our products are often a cost effective alternative to genuine OEM Parts.

Please note: the models of bike we state in our listings are for general guidance only. Please make sure this item will fit your bike before purchasing. Also, we cannot guarantee fitment to any non-UK models.