Athena - Big Bore Extreme cylinder kits
Italian performance specialist Athena has been expanding its replacement and upgrade cylinder kit range for off-road applications this year with their high performance Big Bore Extreme range.
The complete line-up of cylinder kits developed for the leading 250 cc 4-stroke motocross platforms turns a "new idea of performance into reality for the major off-road applications. This range has been designed to deliver more substance, stronger drive and an even more engaging riding experience, without compromising the balance and rideability of the original platforms.
"From this vision comes a technical package capable of taking 250 4-stroke machines into the 300 cc range, opening up a new dimension in off-road riding."
At the heart of the package is the 85 mm bore cylinder, engineered to withstand the typical demands of the most severe off-road use. Its architecture combines a steel liner co-cast into an aluminum body, a technical solution that helps ensure dimensional stability, wear resistance and consistent performance even under the harshest operating conditions. The increased bore makes it possible to bring displacement into the 300 cc range, without requiring any machining to the crankcases.
The aluminium alloy piston is designed specifically for larger bores and engineered to handle the higher mechanical and thermal loads generated by this configuration. The technical package also includes a molybdenum disulfide-coated skirt, DLC-coated pin, and chromium nitride-coated special steel piston rings, with the aim of optimising sliding performance, wear resistance, durability and operating consistency. "The gasket set, specifically developed for each Big Bore Extreme application, completes the system by ensuring assembly precision, full compatibility with the kit, and resistance to the high temperatures generated by off-road use."
On the electronics side, the system is completed by GET Boost, the pre-configured hardware module developed in collaboration with GET, the Group's electronics brand - designed specifically to work in combination with the cylinder kit. This solution allows the stock ECU to be retained while optimizing combustion management and fuelling strategies, thereby maximizing the performance potential unlocked by the cylinder kit.
The Big Bore Extreme range is currently available for the following applications:
• Honda CRF250R, model years 2018-2026
• Yamaha YZ250F, model years 2019-2024
• Kawasaki KX250, model years 2023-2026
• KTM 250 SX-F and Husqvarna FC 250, model years 2016-2022
• GasGas MC 250F, model years 2021-2023
In other news, Athena is to take centre stage again as the official partner for the Centenary Edition of the FIM International 6-Days of Enduro at Alentejo, Portugal on October 12-17, 2026.
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