Yamaha YZ125 / YZ125X 54mm Athena Stock Bore Cylinder Top End Rebuild Kit (2005–2022)

🛠️ Description
Bring your Yamaha YZ125 back to life with this complete Athena Stock Bore Cylinder Kit. Designed for 2005–2021 YZ125 and 2020–2022 YZ125X, this 54mm OEM-spec top end rebuild kit restores power, improves cooling efficiency, and includes everything you need for a professional-level refresh. Engineered with premium materials and precision machining, this is the most complete OEM-style solution available.

✅ What’s Included

• Athena 54mm OEM Stock Bore Nikasil Cylinder (125cc)

• Athena Cast-Lite Flat Top Piston Kit (piston, rings, wrist pin, circlips)

• Athena Complete Top End Gasket Set (all seals and hardware)

• Athena Cylinder Head w/ Removable Bronze Dome (anti-detonation, high-compression design)

• Athena High-Performance Hard Anodized Power Valves (OEM valves not compatible)

• All brand-new parts backed by Athena warranty

📦 Fitment

• Yamaha YZ125 (2005–2021)

• Yamaha YZ125X (2020–2022)

🛡️ Warranty Info

• Backed by Athena’s manufacturer warranty

• Professional installation is strongly recommended

• Warranty does not cover failures from improper installation, tuning errors, or incorrect break-in

🔑 Key Features

• Stock bore 54mm (125cc) for OEM-style rebuilds

• Aluminum cylinder with nickel-carbide plating & enlarged water jackets for cooling

• Includes Athena high-performance anodized power valves (not OEM compatible)

• Cylinder head with removable bronze dome for compression tuning & anti-detonation

• Complete bolt-on solution, no machining required (unless otherwise noted)