Yamaha YZ125 54mm Athena Stock Bore Cylinder Top End Rebuild Kit (1997–2004)

🛠️ Description
Restore your Yamaha YZ125’s factory performance and reliability with this complete Athena Stock Bore Cylinder Kit. Designed for 1997–2004 models, this 54mm top end rebuild kit includes everything you need for a proper refresh — cylinder, piston, gaskets, head, power valves, and hardware. Built with precision-machined aluminum and nickel-carbide coating, it’s the strongest, most complete OEM-style solution on the market.

✅ What’s Included

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

• Athena Coated Piston Kit (piston, rings, wrist pin, circlips)

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

• Athena Cylinder Head w/ removable bronze dome insert

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

• Athena Head Stud Kit

• All parts brand new and backed by Athena warranty

📦 Fitment

• Yamaha YZ125 (2-Stroke)

  • 1997 YZ125

  • 1998 YZ125

  • 1999 YZ125

  • 2000 YZ125

  • 2001 YZ125

  • 2002 YZ125

  • 2003 YZ125

  • 2004 YZ125

🛡️ Warranty Info

• All components covered by Athena’s manufacturer warranty

• Must be installed by a qualified technician to ensure proper performance

• Warranty does not cover improper installation, tuning errors, or break-in issues

🔑 Key Features

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

• Aluminum cylinder with nickel-carbide plating for durability

• Includes high-performance Athena power valves (cannot use OEM valves)

• Cylinder head with removable bronze dome insert for optimal combustion and anti-detonation

• Complete kit with piston, gaskets, studs, and hardware

• Bolt-on installation, no case machining required