10/08/2026
Now Available
The Athena Big Bore Extreme for 250cc Yamaha
The standard Yamaha engine is considered one of the best in the first part of power delivery: the initial thrust is exceptionally powerful, even though it is within the medium and high steady states, and strong initial progression seems to stabilize a lot.
Athena's Big Bore Extreme increases the displacement up to 304 cc, bringing the bike to have a very strong, effective and consistent engine output over the entire arc of the power delivery curve.
The entire kit guarantees maximum performance, better delivery, greater torque at low and medium steady states, better reactivity and - at the same time - the same reliability as original parts, thanks to all the technical devices resulting from the challenge won by the Athena R&D team: all this is combined with the proverbial good handling of a 250cc Offroad for a simply exceptional driving experience.
The kit includes the aluminum alloy cylinder, the forged piston complete with pin and rings, and all the necessary gaskets.
