This Wossner piston kit with a 56.75mm bore (+0.75 oversize) and 56.69mm measured bore is designed for Yamaha YZ125 models from 1983 and 1985. The forged construction ensures high strength and improved thermal transfer. The piston’s elliptical shape distributes thrust loads evenly, reducing the risk of piston collapse. Manufactured in Germany.

Features

• Forged construction for enhanced strength


• Effective heat transfer from combustion chamber to cylinder walls


• Elliptical design ensures uniform pressure distribution


• Made in Germany

Specifications

• Bore Size: 56.75mm


• Bore (Actual Measured): 56.69mm


• Display Volume: 83 cm³


• Stroke: 84.00mm


• Clearance: 0.06mm


• Compression Ratio (Wossner): 2-stroke


• Compression Ratio (OEM): 2-stroke


• Compression Height: 30.80mm


• Dome Volume: Not specified


• Theoretical Weight: Not specified


• Lock Part Number: CW16


• Pin Part Number: WP036


• Ring Set Part Number: RSB5600

Cross-Reference OEM Part Numbers

• 39W-11-630-00-00


• 55Y-11631-00-94

Vehicle Fitments

• Yamaha YZ125 1983


• Yamaha YZ125 1985