Wiseco Piston Kit - 66.40 Mm - Yamaha Yz250/Yz250X 804M06640

• Forged from high-silicon aluminum alloy for maximum strength and dependability • Wiseco offers a complete range of popular piston models and years for both trail and racing applications • Durability, longevity and increased horsepower • Innovative forging design and piston skirt provide maximum horsepower and torque • Features forged pistons, rings, wrist pins, and circlips • These high-tech piston designs offer maximum compression ratios, ultra-stiff strutted forgings, and titanium nitride-coated rings, which all add up to more power that is sustained longer • Each piston is E-Coated on the crown, ring grooves, and pin bore, for maximum wear resistance and protection from micro-welding, galling, and detonation • GP Series parts generally have less machining on the outside, which helps seal up the bore for increased compression • Additionally, boost ports are removed for a more predictable powerband and increased pull on the top end • Cylinder sleeves must be purchased separately. • Service intervals may be increased with Racer's Choice pistons over conventional Wiseco pistons, and are for expert racers and tuners only. - Yamaha YZ 250 (2003, 2006, 2016, 2024, 2004, 2015, 2018, 1999, 2000, 2010, 2013, 2017, 2019, 2020, 2007, 2023, 2014, 2008, 2021, 2001, 2009, 2012, 2025, 2002, 2005, 2011, 2022); Yamaha YZ 250 X (2020, 2024, 2018, 2023, 2016, 2021, 2025, 2017, 2019, 2022); Yamaha YZ 250 Monster Energy Racing (2023, 2022)