Big Bore Cylinder Kit Ø85mm | 290cc

Take your Honda CRF 250R to the next performance level with the Athena Big Bore cylinder kit featuring GET Boost technology, engineered to deliver a stronger, more responsive, and more enjoyable power delivery across the entire rpm range.

Designed for riders seeking increased mid‑range torque, quicker throttle reaction, and a more assertive power curve, this kit combines Athena’s racing‑grade engineering with the advanced architecture of Honda’s latest 250 platform.

More torque, quicker acceleration, better control

The kit includes a big bore aluminum cylinder made from a high‑silicon alloy with an integrated steel liner, ensuring excellent thermal stability and efficient combustion under sustained racing loads. The high‑performance forged piston, supplied with pin and rings, is precisely engineered to match the increased bore and maintain durability, smoothness, and optimal sealing.

The outcome is a more responsive engine with stronger torque, improved acceleration, and faster throttle reaction during corner exits, rhythm sections, and technical track conditions.

GET Boost electronic module included

The kit comes with the GET Boost electronic module, developed by GET, Athena’s in‑house electronics division. Preconfigured specifically for the CRF 250R Big Bore setup, it enhances combustion and fueling strategies without requiring ECU replacement or modifications.

Plug‑and‑play installation and seamless integration

The GET wiring harness connects directly to the injector and throttle body connectors, offering a quick, non‑invasive installation. The dedicated Boost calibration ensures safe, consistent performance with a power curve tailored to the new cylinder configuration.

Athena racing‑grade manufacturing

The forged piston is CNC‑machined for reduced friction and increased mechanical strength, while the high‑strength piston pin ensures long‑term reliability under elevated loads. All components follow Athena’s racing‑derived manufacturing standards for precision and durability.

Complete kit, ready for assembly

All required gaskets are included, making the kit ready for professional installation within OEM Honda tolerances.

The Athena Big Bore cylinder kit with GET Boost is the ideal upgrade for riders wanting a more powerful, more responsive, and more exhilarating Honda CRF 250R.