Cylinder Works 20009-K02 99-23 Yamaha YZ 250 250cc Standard Bore Cylinder KitCylinder Works 20009 K02 99 23 Yamaha YZ 250 250cc Standard Bore Cylinder Kit Description Cylinder Works Standard Bore Cylinder Kit Fits Models YZ 250 (99 24) Specs Uses Vertex #22584 Compression RatioSTD Cylinder Diameter66. 400 mm Cylinder Kit Type: Standard Bore Displacement: 250 cc Engine Type: 2 Cycle Includes: Cylinder, Cylinder Head, Piston Kit, Top End Gasket Kit, Wrist Pin Bearing Power Valve Kit