Athena Big Bore Cylinder Kit for Yamaha YZ 250 2T, increasing displacement to 293cc with a bore diameter of 72.00mm (+5.60mm over stock). Engineered in Italy, this kit includes a high-quality aluminum cylinder with a nickel-silicon coating for durability and wear resistance. Designed for direct installation without modifications to the engine crankcase.

Features

• Increases displacement to 293cc


• Bore diameter: 72.00mm (+5.60mm over stock)


• Compression ratio: 15.0:1


• Nickel-silicon coated for wear resistance


• Includes all necessary components for installation


• No modifications required to the engine crankcase

Specifications

• Bore Diameter: 72.00mm


• Bore Gain: +5.6mm


• Compression Ratio: 15.0:1


• Displacement: 293cc


• Net Weight: 3.50 kg

Included Components

• Aluminum cylinder


• Cylinder head


• Complete piston (with piston pin and rings)


• Exhaust valve kit


• Gasket kit

Cross-Reference OEM Part Numbers

• S4F07200006A (Piston Kit 71.95mm)


• S4F07200006B (Piston Kit 71.96mm)


• P400485160183 (Gasket Kit)


• S410485308029 (Cylinder Head)


• S410485303025 (Valve Assy Kit)


• S41316257 (Rings)

Vehicle Fitments

• Yamaha YZ 250 2T (2003-2025)