PISTON KIT 87-07 YFS200 66.25, WOSSNER 8101D025 YAMAHA ATV

The Wossner 8101D025 piston kit is designed for Yamaha YFS200 Blaster models from 1988 to 2006, featuring a 66.25 mm bore for +0.25 mm oversize applications. Manufactured in Germany using forged construction, this piston delivers superior durability and efficient thermal conductivity. The elliptical design ensures even thrust load distribution during piston expansion, reducing localised pressure and minimising the risk of piston collapse. The kit includes all necessary components for a dependable engine rebuild.

Features

• Forged piston construction for high strength and heat resistance

• Optimised combustion chamber heat transfer to cylinder wall

• Elliptical profile provides uniform bearing surface under thermal expansion

• Minimises localised stress and helps prevent piston collapse

• Precision-manufactured in Germany

Specifications

• Bore Size: 66.25 mm

• Actual Bore Diameter: 66.19 mm

• Stroke: 57.00 mm

• Display Displacement: 199 cm³

• Clearance: 0.06 mm

• Compression Ratio (Wossner and OEM): 2-stroke

• Compression Height: 29.90 mm

Cross-Reference Wossner Part Numbers

• Piston Kit: 8101D025

• Lock: CW16

• Pin: WP027

• Ring Set: RSB6625 (Quantity: 2)

• Rod: P2030

• Part No.: 56-W573+025.WO

Vehicle Fitments

• Yamaha YFS200 Blaster (1988–2006)