Engine Fastener Kits come with modern dimpled flange bolts. Two-Stroke Engine Fastener kits have all the external fasteners from top to bottom-end including hardware for: Heads, Reeds, Cylinder, Crankcase, Case Saver, Water Pump, Left Case Cover, Ignition Cover, Inner & Outer Clutch Covers, Power Valve Covers. With a bright zinc finish, these fasteners last long and give a clean, updated look to any engine. Fits: Yamaha YZ250 90-21, YZ250X 16-21