Shopping Cart
There are no more items in your cart
Yamaha YZ 125, in its latest generation, is distinguished by its outstanding engine power and agile chassis, offering prompt throttle response and flawless cornering handling. The delivery is well balanced, providing a significant power boost without sacrificing maneuverability. The transmission offers smooth gear changes, allowing the rider to maintain control in any situation.
For those who want to take their Yamaha YZ 125 to the next level, Athena introduces the new Big Bore Thermal Assembly, the ultimate upgrade over the standard cylinder, designed to maximize power and fun on the track.
Advanced Technology for Superior Performance
Athena's Big Bore Thermal Group increases displacement to 144 cc, unleashing a burst of power that can be felt from the first hit of the gas. Thanks to advanced engineering design and intensive dyno and track testing, this kit turns every acceleration into a thrilling experience, with boost that continues to grow linearly at all rpm and never seems to end.
The Cylinder: Unrivaled Performance
The heart of the thermal unit is, of course, the aluminum cylinder, designed with optimized geometries to maximize combustion efficiency. The intake and exhaust ports are designed to ensure optimal gas flow. The cooling tanks are designed to prevent overheating even during the most demanding sessions. The Athena Big Bore cylinder maintains a smooth and balanced delivery throughout the rpm range, turning riding the YZ 125 into a memorable experience.
Decomposable cylinder head: Power to Measure
Another highlight is the decomposable cylinder head, consisting of an aluminum outer shell and a bronze inner dome. This configuration was also created to leave room for customization of the squish and compression ratio. Other benefits include improved heat dissipation and a consequent increase in engine reliability and durability, which is especially crucial in an extreme off-road environment. The dome, which is self-centering and recessed into the cylinder bore, ensures a perfect seal and optimal combustion for smooth and consistent power delivery. Flexibility and superior performance are key aspects especially on 2T engines where every detail can really make a difference.
Exhaust Partition Valves: Strength and Reliability
The valves are made of Ergal 7075 with hard anodizing, ensuring high temperature resistance and light weight. Designed with extreme precision, these valves ensure a tight seal, preventing compression loss and maintaining combustion efficiency for consistent and reliable power.
Complete Kit for Total Reliability
In keeping with Athena's tradition, the Big Bore thermal assembly includes a high-quality gasket kit designed to ensure complete installation. Each gasket is made to withstand even extreme track conditions, ensuring a perfect seal and long engine life.
The Ultimate Upgrade for Your Yamaha YZ 125
The Athena Big Bore Thermal Assembly is not just a replacement; it's a manifesto of pure power and unwavering reliability. By installing this kit, every turn will bring a smile and every throttle opening will become a delight.
Your Yamaha YZ 125 will become the perfect weapon for any track, ready to respond with surgical precision and unleash an irresistible force.
Reviews 
