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Athena P400485100073 304cc Big Bore Cylinder Kit (85mm Bore) - Forged Piston Performance Upgrade, Converts 250cc to 304cc, Compatible with Yamaha YZ250F & WR250F 2019-2023

Description

UPGRADE YOUR DIRT BIKE TO THE NEXT LEVEL OF PERFORMANCE Extract massive power, aggressive low-end torque, and unmatched acceleration from your 250cc four-stroke engine with the Athena Big Bore Cylinder Kit (Part No. P400485100073), a premium race-proven package engineered in Italy to seamlessly convert your factory setup into a high-revving, high-output 304cc powerhouse. Entirely cast from high-grade aluminum and treated with a specialized Motor-Nicksil (Nickel-Silicon) coating, this cylinder guarantees exceptional thermal dissipation, minimal friction, and optimal wear resistance to deliver a substantial increase along the entire power curve while maintaining strict original-equipment reliability. This complete bolt-on kit comes loaded with everything required for a flawless installation—including a widened water-jacket aluminum cylinder, a high-performance forged piston coated with molybdenum, premium rings, wrist pin, clips, and a specific high-tightness multi-layer gasket set—allowing you to dramatically increase track performance without requiring any machining or structural engine modifications to your factory crankcase.

Athena P400485100073 304cc Big Bore Cylinder Kit (85mm Bore) - Forged Piston Performance Upgrade, Converts 250cc to 304cc, Compatible with Yamaha YZ250F & WR250F 2019-2023

Product form

SKU: P400485100073

UPGRADE YOUR DIRT BIKE TO THE NEXT LEVEL OF PERFORMANCE Extract massive power, aggressive low-end torque, and unmatched acceleration from... Read more

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$1,102.95

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    • Shipped today? Order within: Jul 09, 2026 14:00:00 -0500
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    Description

    UPGRADE YOUR DIRT BIKE TO THE NEXT LEVEL OF PERFORMANCE Extract massive power, aggressive low-end torque, and unmatched acceleration from your 250cc four-stroke engine with the Athena Big Bore Cylinder Kit (Part No. P400485100073), a premium race-proven package engineered in Italy to seamlessly convert your factory setup into a high-revving, high-output 304cc powerhouse. Entirely cast from high-grade aluminum and treated with a specialized Motor-Nicksil (Nickel-Silicon) coating, this cylinder guarantees exceptional thermal dissipation, minimal friction, and optimal wear resistance to deliver a substantial increase along the entire power curve while maintaining strict original-equipment reliability. This complete bolt-on kit comes loaded with everything required for a flawless installation—including a widened water-jacket aluminum cylinder, a high-performance forged piston coated with molybdenum, premium rings, wrist pin, clips, and a specific high-tightness multi-layer gasket set—allowing you to dramatically increase track performance without requiring any machining or structural engine modifications to your factory crankcase.

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