Meet the ones who push Athena to the limit
Stop imagining. Start riding.
NEW EXTREME BIG BORE CYLINDER KIT RANGE.
Cylinder kits for 250cc off-road bikes, built to turn the power you imagined into reality.
Athena introduces the new Big Bore Extreme cylinder kit range, developed for the most popular off-road platforms from the leading brands. This range has been engineered to take a 250 to a displacement that reaches and exceeds 300 cc, opening up a new frontier in off-road performance.
This is not a simple stock replacement, nor a conventional displacement upgrade: it is the most advanced evolution of Athena big bore technology. For over 50 years, we have been developing mechanical and electronic engine components. With Big Bore Extreme, we decided to go even further, transforming an existing platform into something bigger, fuller and more aggressive, without compromising the agility and handling that make a 250cc so unique.
Because this is not just about bore size. It is about an engine that responds faster on the throttle, delivers stronger drive and feels more commanding out of the corner.
Why Extreme?
Because every engine has a limit. We chose to rewrite it.
Big Bore Extreme was born from a clear decision: to engineer each kit with a dedicated, application-specific approach, rather than adapting a generic solution to different bikes.
Behind every cylinder kit is the work of Athena’s R&D department, which develops custom geometries, fitments, and technical solutions for each application. This know-how has been built through decades of experience in OEM development, collaboration with some of the world’s most renowned off-road teams, and a deeply rooted Made in Italy culture of engineering and technical expertise.
And it does not stop at the design stage: every kit is tested in-house, from the dyno to the track, to turn engineering into a real riding sensation.
The drive and character of a 450. The lightness and agility of a 250.
It starts with a 250 platform, with targeted bore upgrades to increase displacement and deliver more torque, stronger low- and mid-range response and a fuller power delivery.
You feel the advantage as soon as you ride: the presence of a larger displacement, combined with the agility, light weight, and handling of the original platform.
In other words: more drive out of the corner, quicker response, and more engine in every twist of the throttle.
A bike that stays compact, but plays in a different league.
Extreme, yet Plug & Play
The power takes a big step up. The installation stays smart.
Big Bore Extreme has been developed to make the upgrade as direct as possible, both mechanically and electronically.
The goal is simple: to let you work on your bike on your own, with a solution designed to integrate precisely, without turning installation into a major project.
The kit is designed to increase bore size and displacement without requiring any machining of the engine cases. A real advantage that makes the upgrade more accessible, quicker to complete and easier to manage independently, while minimizing the margin for error during installation.
The electronic side follows the same philosophy: dedicated components, pre-engineered connections and seamless integration. The result is a system that takes the engine to a new level of performance, while maintaining an approach that is rational, clean, and unmistakably Athena.
INSIDE EXTREME
Explore the full range
Ten applications. One language: Extreme.
The Athena Big Bore Extreme range was created to bring the same vision to different platforms, respecting the character of each bike and enhancing its potential through dedicated engineering.
Each part number is developed for a specific application, with the goal of delivering a radical yet balanced upgrade, ready to transform engine response without compromising the bike’s overall balance.
Choose your application and discover the dedicated kit.
HONDA, from 2018 to 2026
YAMAHA, from 2019 to 2024
KAWASAKI, from 2023 to 2026
KTM, from 2016 to 2022
Developed in-house. Proven where it matters.
HONDA RACING REDMOTO ENDURO TEAM
3 atleti
MGR-ASI KAWASAKI TEAM
1 atleta
Francesca Nocera