Athena Big Bore Cylinder Kit P400250100011 — Kawasaki KX125 2003-2007

Athena Big Bore Cylinder Kit P400250100011 — Kawasaki KX125 2003-2007

Product Description

Unlock the hidden potential of your machine with the Athena Big Bore Cylinder Kit. Engineered to increase your displacement to a competitive 144cc, this kit is designed for riders who need that extra grunt to clear jumps and dominate the track. By replacing your stock top end with this premium aluminum cylinder, you gain significant torque and a wider, more usable powerband, elevating your bike's overall performance to race-winning standards.

The cylinder features a specialized nickel carbide coating for superior heat transfer and long-lasting durability, even under the most demanding racing conditions. The kit is comprehensive, including an aluminum cylinder head with a removable bronze dome for optimized combustion efficiency, and a high-performance Cast Lite piston kit. Athena also includes a full top-end gasket set and custom hard-anodized power valves—specifically engineered for this cylinder's geometry—to ensure perfect reliability and power delivery.

Top Features: Athena Big Bore Cylinder Kit

• Increases displacement to 144cc for enhanced competitive power
• Lightweight aluminum cylinder with nickel carbide coating for reduced friction
• Includes specialized, high-performance hard anodized power valves
• Aluminum cylinder head features a removable bronze dome for improved cooling
• Comprehensive kit includes Cast Lite piston, rings, clips, pin, and top-end gaskets

Please review the detailed compatibility data below to ensure an exact fitment match for your motorcycle before finalizing your purchase.

Fitment List

Year Range	Vehicle Brand	Vehicle Model & Sub-Model
2003-2005	Kawasaki	KX125
2006-2007	Kawasaki	KX125

Frequently Asked Questions

Q: Is this a bolt-on kit, or do I need to modify my engine cases?
A: This kit is designed to bolt directly onto your stock engine cases. However, because you are increasing displacement, you will need to re-jet your carburetor to ensure the engine receives the proper air-fuel ratio for the increased size.

Q: Why are the included power valves different from OEM?
A: Athena uses custom-profiled power valves to match the increased port volume and timing of the big bore cylinder. OEM valves are not designed for this specific geometry and will not function correctly with this kit.

Expert Pro-Tip: After upgrading to 144cc, keep a close eye on your cooling system. A larger displacement creates more heat. Ensure your cooling system is in top shape, use a high-quality coolant, and consider upgrading to a higher-pressure radiator cap if you race in extreme conditions to prevent the engine from reaching dangerous temperatures.

Recommended Pairings:
o Kawasaki KX125 Performance Parts & Upgrades
o Premium Motorcycle Chemicals
o Kawasaki 2-Stroke Performance Parts

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