PISTON KIT 86-88 YZ125 57.50, WOSSNER 8118D150 YAMAHA MX

This Wossner 57.50mm (+1.50 oversize) forged piston kit is designed for Yamaha YZ125 models from 1986 to 1988. Produced in Germany, the piston is built using a forged process for enhanced durability and strength. Its elliptical shape helps maintain a consistent bearing surface during thermal expansion, reducing localised stress and evenly distributing thrust loads to prevent piston collapse. The piston also supports efficient heat transfer from the combustion chamber to the cylinder walls, ensuring reliable performance in two-stroke engines.

Features

• Forged piston for increased structural strength and durability

• Elliptical design provides uniform bearing surface during heat expansion

• Minimises localised pressure and evenly distributes thrust loads

• Supports efficient combustion heat transfer to cylinder walls

• Manufactured in Germany

Specifications

• Bore: 57.50mm

• Actual diameter: 57.44mm

• Displacement: 123 cm³

• Stroke: 50.00mm

• Clearance: 0.06mm

• Compression height: 30.00mm

• Compression ratio: 2-stroke

Cross-Reference OEM Part Numbers

• Piston Kit Part No.: 56-W559+150.WO

• Wossner Piston Kit No.: 8118D150

• Lock: CW16

• Pin: WP036

• Ring Set: RSB5750

Vehicle Fitments

• Yamaha YZ125 1986

• Yamaha YZ125 1987

• Yamaha YZ125 1988