GP Series Wiseco pistons are engineered for endurance and high RPM applications. They feature an Electra-Coated crown, ring groove, and pin bore to resist potential wear and heat damage, ensuring long service life and top-end power. The ArmorGlife skirt coating reduces friction, optimizing performance potential. The GP series is ideal for high-performance engines requiring durability and efficiency under extreme conditions.. Electra-Coated crown, ring groove and pin bore resists potential wear, combustion heat damages, and ring micro-welding. ArmorGlife skirt coating reduces friction to optimize performance potential. Designed with optimized features for long service life and top-end power. Extra lightening operations for enhanced throttle response. Engineered, forged, and machined in the USA in Mentor, OH. High-quality ring(s), wrist pin(s), and circlips included. Designed for endurance and sustained-RPM 2-stroke riding. Wiseco 99-18 Yamaha YZ250 GP Series 2614CS Piston Kit. Std, Bore:66.4, Racer's Choice. 66.40 mm Bore

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