Wossner Forged Piston Kit 56.00mm Bore – Yamaha YZ125 1989 (8131DA STD)
This Wossner forged piston kit is designed for the 1989 Yamaha YZ125, featuring a standard bore size of 56.00mm (actual 55.94mm). Built for 2-stroke engine performance, it provides exceptional strength and thermal efficiency through its forged aluminium construction. The piston’s elliptical shape ensures uniform thrust load distribution during thermal expansion, reducing localised pressure and the risk of piston collapse. Manufactured in Germany for consistent quality.

Features

• Forged piston construction for superior strength and reliability

• Engineered to optimise heat transfer from the combustion chamber to the cylinder walls

• Elliptical profile maintains a uniform bearing surface under thermal expansion

• Developed for 2-stroke engines

• Made in Germany

Specifications

• Bore Size: 56.00mm (Standard)

• Actual Bore: 55.94mm

• 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: 8131DA

• Ring Set: RSB5600

• Lock: CW16

• Pin: WP036

• Rod: P2047

• Internal Reference: 56-W582+00A.WO

Vehicle Fitments

• 1989 Yamaha YZ125