Athena Big Bore cylinder kits are a bolt on performance replacement kit specifically designed for each application. The kit includes a new aluminum cylinder with nickel carbide coating designed with wider water jackets, Vertex Forged piston with molybdenum coating, piston pin, rings, clips and all the gaskets required for the job. For Yamaha WRF 250 2001 to 2013 models, brings the CC up to 290cc with a 83mm piston. Standard piston is 77mm.
