Big Bore Cylinder Kit Ø85mm | 300cc

Elevate your KTM 250 SX‑F 2016–2018 with the Athena Big Bore cylinder kit featuring GET Boost technology, engineered to increase displacement and deliver a stronger, quicker, more usable power delivery across the entire RPM range.

Built for riders who want more torque, faster corner‑exit acceleration, and immediate throttle reaction through technical sections, this kit blends Athena’s racing‑grade engineering with the efficiency of KTM’s 250 SX‑F platform.

Stronger torque, quicker corner exits

The kit features a big bore aluminum cylinder made from high‑silicon alloy with an integrated steel liner to ensure thermal stability and consistent combustion under sustained load.
A high‑performance forged piston, supplied with piston pin and rings, is precisely matched to the increased bore to minimize friction, improve sealing, and enhance long‑term reliability.

The outcome is a fuller, more responsive mid‑range, with quicker acceleration and improved drive on low‑grip surfaces and rhythm sections.

GET Boost module included, dedicated calibration

Supplied with the kit is the GET Boost electronic module, developed by GET, Athena’s electronics division. Preconfigured for the 250 SX‑F Big Bore, it optimizes fueling and combustion management without replacing the stock ECU.

Plug‑and‑play installation, clean integration

The GET harness connects directly to the injector and throttle body connectors. The dedicated Boost map delivers a strong, predictable power curve tailored to the new cylinder configuration.

Athena racing‑grade manufacturing

The CNC‑machined forged piston provides reduced friction and high mechanical strength; the high‑strength piston pin withstands increased loads in demanding use. The cylinder is built to Athena’s racing‑derived tolerances for precision, durability, and repeatable performance.

Complete kit, ready to assemble

All required gaskets are included for professional installation within KTM OEM tolerances.

The Athena Big Bore cylinder kit with GET Boost is the ideal upgrade for a KTM 250 SX‑F 2016–2018 that feels stronger, more responsive, and more effective on track—with no compromise on reliability.