- Optimised light design for improved gas delivery and response.
- Modular bronze insert for superior heat dissipation and stability.
- Lightweight single-ring piston to reduce friction and improve efficiency.
- Race-proven reliability for extreme performance and long life.
The latest generation Yamaha YZ 125 sets the benchmark in the 125cc segment thanks to its powerful engine, responsive chassis and impeccable power management. To further enhance these characteristics, Athena introduces the new Standard Bore Racing Cylinder, an advanced solution that improves engine performance through components optimised for maximum race performance.
High-Performance Cylinder
The heart of the kit is the high-performance aluminium cylinder, featuring specific machining on the intake and exhaust ports to optimise flow and ensure more efficient combustion. These modifications improve power delivery, ensuring immediate throttle response and increased performance across the entire range of use. The advanced design of the cylinder helps to reduce turbulence, maximising engine performance and thermal stability during the most intense sessions.
Racing Head with Removable Dome
To ensure superior thermodynamic efficiency, the kit includes a head with a removable bronze dome, designed to optimise heat dissipation and improve resistance to high temperatures. The combustion chamber geometry is designed to increase the speed of the air-fuel mixture, ensuring more linear power delivery and greater reliability in extreme conditions.
Lightweight Single-Ring Piston with Oil Dots
The piston included in the kit is a lightweight single-ring piston, designed to reduce moving masses and improve engine responsiveness. The presence of Oil Dots optimises lubrication, reducing friction and improving component life. This translates into improved smoothness and increased mechanical efficiency, ensuring greater power and wear resistance.
Advantages of the Athena Standard Bore Racing Thermal Unit
? Superior performance – Optimised porting to improve engine delivery and response.
? Advanced heat dissipation – Tested with a removable bronze dome for optimal heat management.
? Reduced weight and increased efficiency – Lightweight single-ring piston with Oil Dots technology.
? Reliability and durability – Components designed to withstand the most extreme stresses.
? Perfect compatibility – Developed with precise tolerances for perfect interchangeability with original components.
A Race-Ready Kit
The Athena Standard Bore Racing Thermal Group is the ideal choice for riders who want to maximise the performance of their Yamaha YZ 125 without compromise. Thanks to advanced design and high-quality materials, this kit offers a significant upgrade over the original components, ensuring smoother power delivery, greater power and superior resistance to the most extreme conditions.
Trust Athena technology to take your Yamaha YZ 125 to the next level and dominate the track with racing-level performance!
Technical specifications
Bore (mm) 54.00
Displacement (cc) 124.00
Net weight (kg) 2.39
Compression ratio 15.0:1
