PISTON KIT 1989 YZ125 57.00, WOSSNER 8131D100 YAMAHA MX

Wossner Forged Piston Kit 57.00mm Bore – Yamaha YZ125 1989 (8131D100 +1.00)
This Wossner forged piston kit is designed for the 1989 Yamaha YZ125 and features a +1.00mm oversize bore (actual 56.94mm). Specifically developed for 2-stroke engines, the piston’s forged construction delivers high strength and excellent heat dissipation. The elliptical design promotes uniform thrust load distribution during heat expansion, preventing localised pressure points and reducing the likelihood of piston failure. Precision-manufactured in Germany.

Features

• Forged aluminium piston for superior durability and strength

• Optimised for efficient heat transfer from combustion to cylinder walls

• Elliptically shaped to ensure even pressure distribution under heat expansion

• Designed for use in 2-stroke engines

• Made in Germany

Specifications

• Bore Size: 57.00mm (+1.00 oversize)

• Actual Bore: 56.94mm

• Compression Height: 28.00mm

• Clearance: 0.06mm

• Stroke: 50.00mm

• Displacement: 123 cm³

• Wossner Compression Ratio: 2-stroke

• OEM Compression Ratio: 2-stroke

Cross-Reference OEM Part Numbers

• Wossner Piston: 8131D100

• Ring Set: RSB5700

• Lock: CW16

• Pin: WP036

• Rod: P2047

• Internal Reference: 56-W582+100.WO

Vehicle Fitments

• 1989 Yamaha YZ125