DYNAMIC RACING / 2019-2025 YAMAHA YZ250F 80mm 270cc BIG BORE PISTON KIT All in one bolt on kit! You can expect an easy 3-4hp from this kit. And another 1-2 with a good dyno tune. One standout feature of this piston kit is its innovative crown design, which enhances combustion efficiency and delivers improved power output. Combined with a custom DLC-coated wrist pin and specially designed rings, this kit ensures premium durability and performance. Kit Includes: -14.7:1 Compression Ratio JE Forged Piston -DLC Coated Wrist Pin: Reduces friction and maximizes durability and performance -Japanese Ring Pack: Provides a secure seal for enhanced performance For optimal performance we recommend pairing this kit with our Vortex ECU and custom maps. Please Note: CYLINDER NOT INCLUDED. We recommend using Cylinder Works Part# CW21013-1