PISTON KIT 86-88 YZ125 56.75, WOSSNER 8118D075 YAMAHA MX
This Wossner 56.75mm (+0.75 oversize) forged piston kit is designed for Yamaha YZ125 models. Featuring a forged build and elliptical design, the piston is engineered for thermal expansion control, even thrust load distribution, and reliable performance in two-stroke engines. Manufactured in Germany, it ensures efficient heat transfer from the combustion chamber to the cylinder walls under demanding conditions. Features include forged piston construction for enhanced strength and durability, an elliptical design providing a consistent bearing surface under thermal expansion, and even distribution of thrust loads that minimises localised stress and prevents piston collapse. Specifications include a bore of 56.75mm, actual diameter of 56.69mm, displacement of 123 cm³, stroke of 50.00mm, clearance of 0.06mm, compression height of 30.00mm, and a compression ratio of 2-stroke. Cross-reference OEM part numbers include Piston Kit Part No.: 56-W559+075.WO, Wossner Piston Kit No.: 8118D075, Lock: CW16, Pin: WP036, and Ring Set: RSB5675.
- SKU
- 56-W559+075.WO
- Brand
- Wossner
- Availability
- Out of Stock
FULL DESCRIPTION
Wossner 56.75mm Forged Piston Kit for Yamaha YZ125
This Wossner forged piston kit is engineered for optimal performance and durability in demanding two-stroke engine applications. With a precise 56.75mm bore, this oversize piston is designed to replace worn or damaged original equipment, restoring power and efficiency.
Key Features:
- Forged piston construction for superior strength and longevity.
- Elliptical design manages thermal expansion for a consistent bearing surface.
- Promotes even distribution of thrust loads, preventing localized stress and piston collapse.
- Optimized for efficient heat transfer from the combustion chamber to the cylinder walls, crucial for high-performance engines.
- Manufactured in Germany to exacting standards.
Specifications:
- Bore: 56.75mm
- Actual Diameter: 56.69mm
- Displacement: 123 cm³
- Stroke: 50.00mm
- Clearance: 0.06mm
- Compression Height: 30.00mm
- Compression Ratio: 2-stroke
Included Components:
- Piston
- Lock Ring: CW16
- Pin: WP036
- Ring Set: RSB5675


