Athena Piston Kit for Yamaha YZ125, 2.124 in (S4F05400011A)

The ATHENA S4F05400011A Piston Kit is designed for Yamaha YZ125 applications requiring dependable performance under demanding riding conditions. Developed with high resistance to mechanical and thermal stresses, this piston kit has been tested on engine dynamometer benches under progressive stress loads and subsequently validated on the track. This testing helps ensure reliable operation during intense motocross and off-road use.
The piston is manufactured by reverse extrusion, a process that supports consistent construction and durability. It is engineered for use with the original equipment cylinder, helping provide proper compatibility for the intended Yamaha YZ125 application. The included piston rings are designed to reduce friction against the OE cylinder, supporting smoother operation and improved engine performance.
Built for riders and technicians seeking a performance-focused replacement component, the ATHENA piston kit combines application-specific engineering with testing in extreme conditions. Its 2.124-inch piston size and OE-cylinder design make it a suitable choice for maintaining or upgrading compatible Yamaha YZ125 engines. Verify application details before installation to ensure the kit matches the engine configuration and service requirements.

Features:

• Application: Designed for Yamaha YZ125 engines

• Brand: ATHENA

• Part Number: S4F05400011A

• Piston Size: 2.124 inches

• Construction: Manufactured by reverse extrusion for consistent strength

• Durability: Tested for resistance to mechanical and thermal stresses

• Testing: Validated on engine dynamometer benches and under track conditions

• Piston Rings: Designed to reduce friction with the OE cylinder

• Compatibility: Engineered for use with the original equipment cylinder

Ships from Parts Unlimited.