AZQP / Cylinder Works / Athena / Hotrods Complete Motor Rebuild Kit! This is the best and most reliable rebuild kit on the market! Fits Yamaha YZ250F Dirt Bikes. Years 2016 2017 2018. This Complete Rebuild Kit Includes. Athena 77mm Stock Bore Nikasil Cylinder. Larger Water Jackets For Better Cooling! Athena Forged & Coated 13.5:1 Piston Kit (Includes, Piston, Pin, Rings & Clips) (Perfect For Pump Gas). Complete Top End Gasket Set. Hotrods Complete Heavy Duty Crankshaft Assembly (Includes Heavy Duty Rod). Hotrods Heavy Duty Crank Main Bearings. Complete Motor Gasket Set. Bottom End Seal Kit. Hotcams Heavy Duty Cam Chain. It will work with your stock head and valves.