- Cylinder redesigned with a new distribution diagram
- Recessed head for more efficient combustion
- Lightweight moulded piston for improved responsiveness
- Exhaust valves optimised for aggressive thrust
The Yamaha YZ 250 has always been synonymous with explosive performance and benchmark agility in the world of motocross. For those looking for a radical upgrade, Athena presents the new Big Bore Thermal Group, designed to transform your YZ 250 into an even more powerful and responsive racing machine.
Technical evolution for extreme performance
This new version of the Big Bore thermal group represents a significant evolution from the previous one. Each component has been redesigned and optimised to offer more power, greater reliability and a more aggressive response across the entire power range.
Revised cylinder: new diagram, new thrust
The aluminium cylinder has been completely redesigned with a new distribution diagram, designed to improve gas flow and maximise combustion efficiency. The internal geometries are optimised to ensure more decisive thrust at medium and high revs, without sacrificing smoothness at low revs.
Recessed head: precision and control
The new head embedded in the cylinder is the result of cutting-edge engineering. The shape and volumes have been improved to optimise squish and compression ratio, ensuring more efficient combustion and smooth, controlled power delivery. The result is more precise handling, with immediate response when opening the throttle.
Fuso piston: lightness and responsiveness
The new, lighter and more efficient moulded piston reduces moving masses and improves engine responsiveness. This translates into increased acceleration and reduced vibrations, for a smoother and more aggressive ride.
Optimised exhaust valves: more aggressive, same handling
The exhaust valves have been completely redesigned, contributing to a more aggressive exhaust diagram. This improvement provides more decisive thrust at high revs, while maintaining good torque at low revs, for optimal handling in all driving conditions.
Complete kit: easy installation, guaranteed reliability
In keeping with Athena tradition, the thermal unit is supplied with a high-quality gasket kit, designed to withstand the most extreme conditions. Each component is designed to ensure perfect sealing and a long engine life, even in the most difficult conditions.
Your ultimate upgrade for the YZ 250
The Big Bore Athena thermal kit for Yamaha YZ 250 is not just a spare part: it is a statement of intent. Power, precision and reliability come together in a kit designed for those who want to dominate the track and push their bike to the limit.
With Athena, every turn becomes an opportunity to push the limits. Every acceleration turns into pure adrenaline.
Technical specifications
| Engine capacity (cc) | 293,00 |
