Athena 144cc Big Bore Piston Kit 57.94mm Bore 14:1 CompressionFor 1997-2021 Yamaha YZ125 2-Stroke ModelsFeatures:Athena, leader in producing motorcycle spare parts for over 40 years, unveils its new range of 4-stroke off-road cast pistons. Produced with cutting-edge CNC machining tools, which ensure dimensional tolerances of less than 0.01 mm, Athena pistons are made of a special high-performance aluminum alloy with high silicon content that guarantee the same reliability of the OE piston, while at the same time providing greater resistance and excellent performance. The perfectly smooth profile ensures a regular flow and the perfect flame propagation.Some pistons skirts are moreover treated with a molybdenum disulfide coating applied by screen printing which further reduce friction to enhance performance and durability.Athena engineers ensure advanced technical solutions and the highest quality standards equal to or better than those adopted in OE production, so as to guarantee performance and reliability.Each piston, engineered in Italy by Athena R&D department, is tested on engine dynamometer benches under progressive stress load, and thereafter on track to validate its performance even in the most extreme conditions.The proven quality of Athena pistons is offered at an extremely affordable price.This piston for Athena Big Bore cylinder is equipped with piston rings that guarantee less friction with the cylinder and therefore a higher performance.Athena takes care of the development of the pistons down to the smallest detail: the rings are produced in Japan with wear-resistant coatings (PVD or chromium nitride) to increase the retain and the durability. The rings perfectly adapt to the cylinder liner even at low tangential load.This piston kit contains the piston, the pin, the circlips, and the piston rings. All components are replaceable and interchangeable in case of need.All Athena products produced in greater displacement and power than those provided by the road code of the user’s country, are intended exclusively for competitive use. Athena declines all responsibility for any use of the product contrary to national regulations.Guarantee of compliance should not be applicable to products destined for competitive sports use or which are used in high-performance or high-speed applications unless it is a clear case of faultiness.Fitment:1997-2021 Yamaha YZ125 2-Stroke Models