Vertex Piston Kit for Yamaha YZ125 and YZ125X, 53.94 mm (23119B)

The Vertex 23119B Piston Kit is designed as a cast OE replacement for select Yamaha YZ125 and YZ125X two-stroke applications. Manufactured from gravity-cast aluminum alloy with an 18% silicone content, this piston is engineered to provide dependable performance, consistent operation, and long service life in demanding riding conditions. Its OE-style cast construction makes it a practical choice for engine rebuilding and routine top-end service.
The piston is heat treated using a T-5 hardening and tempering cycle to improve strength and durability. A high-tech molybdenum disulfide coating on the piston skirt helps reduce friction during initial operation, supporting faster break-in and helping extend piston life. The 53.94 mm piston size is suited for compatible Yamaha engine applications and should be verified against the motorcycle’s service specifications before installation.
Each Vertex 23119B kit includes the essential components required for installation, including the piston, piston rings, wrist pin, and circlips. This complete configuration helps simplify top-end repairs while ensuring the primary replacement components are matched for the application. For proper fitment and reliable performance, follow the manufacturer’s service procedures and use the recommended break-in process after installation.

Features:

• Brand: Vertex

• Part Number: 23119B

• Application: Select Yamaha YZ125 and YZ125X models

• Piston Type: Cast OE replacement piston

• Material: Gravity-cast aluminum alloy with 18% silicone content

• Heat Treatment: T-5 hardening and tempering cycle

• Skirt Coating: Molybdenum disulfide coating for faster break-in and reduced friction

• Kit Contents: Piston, rings, wrist pin, and circlips

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