Big Bore Cylinder Kit Ø 85 mm, 304 cc to increase performance

Unlock the full potential of your Yamaha YZF 250 with Athena’s Extreme Big Bore Kit, designed to increase displacement and deliver more torque and power across the entire RPM range. This kit is ideal for riders looking to push their engine beyond stock limits while maintaining the agility and responsiveness that make the YZF 250 a top choice in offroad racing.Performance upgrade for Yamaha YZF 250The kit includes a high-grade aluminum cylinder with an oversized steel liner, a forged performance piston with pin and rings, and all necessary gaskets. Developed through Athena’s extensive racing experience, this kit ensures smooth and powerful power delivery at all RPMs.GET Boost module included for optimized performanceThe kit features the GET Boost electronic module, developed by Athena’s GET division—renowned for its work with top MXGP and AMA teams. Pre-calibrated for this specific setup, GET Boost installs easily without ECU or wiring modifications, unlocking the full potential of your engine.Easy installation and seamless integrationGET Boost connects directly to the injector and throttle body via a dedicated harness. The module is pre-mapped to deliver safe, reliable performance with a power curve tailored to the new cylinder.Advanced construction and materialsThe cylinder is made from high-silicon aluminum alloy with a steel liner fused using Athena’s proprietary co-casting process, ensuring optimal heat transfer and combustion sealing. The forged piston, CNC-machined and coated with molybdenum disulfide, offers reduced friction and enhanced durability. The DLC-coated pin ensures maximum hardness and reliability.High-quality gaskets includedThe MLS (Multi-layer Steel) head gasket is laser-cut from stainless steel to ensure perfect sealing and long-term durability, even under extreme conditions.Take your Yamaha YZF 250 to the next levelAthena’s Big Bore Kit with GET Boost is the ultimate upgrade for riders seeking more power, torque, and excitement from their YZF 250. Experience the thrill of enhanced performance—on the track or offroad.