Vertex Piston Kit Cast Replica 23119B (53.94mm) — Yamaha YZ125/X 2005-2022

Vertex Piston Kit Cast Replica 23119B — 2005-2022 Yamaha YZ125/X (53.94mm)

Product Description

Bring back the crisp, high-RPM power of your Yamaha 125 with the Vertex Cast Replica Piston Kit (23119B). Precision engineered as a direct factory OE replacement, this kit features a 53.94mm piston designed specifically for the 2005–2021 Yamaha YZ125 and the 2020–2022 Yamaha YZ125X off-road models.

Vertex cast pistons are constructed from a gravity-cast aluminum alloy featuring an 18% silicone content. This advanced metallurgy heavily reduces thermal expansion, ensuring the piston maintains its exact shape under intense 2-stroke operating temperatures. Combined with a factory-applied Molybdenum Disulphite skirt coating, this kit guarantees accelerated break-in times, reduced internal friction, and an extended top-end lifespan.

Top Features: Vertex Piston Kit

• Direct OE Replacement: Designed to look, fit, and perform exactly like the original factory equipment.
• High-Silicone Content: 18% silicone content stabilizes the piston structure and prevents distortion under extreme heat cycles.
• Moly-Coated Skirt: The high-tech Molybdenum Disulphite coating minimizes friction to safe-guard against premature scuffing.
• T-5 Heat Treatment: Undergoes a full hardening and tempering cycle to elevate overall component durability.
• Complete Setup: Includes the precision-ground piston, premium piston rings, wrist pin, and replacement circlips.

Fitment List

Year Range	Vehicle Model
2005-2021	Yamaha YZ125
2020-2022	Yamaha YZ125X

Frequently Asked Questions

Q: Can I use this cast piston if my cylinder has a standard bore size?
A: Yes, this 53.94mm piston is an "A" or standard size replica meant to drop cleanly into a healthy, factory-spec 54.00mm bore cylinder. Always measure your cylinder with a bore gauge to verify clearance tolerances prior to completing assembly.

Expert Pro-Tip: When installing the new circlips, always block the crankcase opening with a clean rag. This prevents an accidental slip from dropping a circlip into the bottom-end of your engine. Ensure the circlip gap faces away from the removal notch on the piston pin bore.

Recommended Pairings

• Essential Off-Road Motorcycle Tools
• High-Performance Premix & Gear Oils

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