Cylinder Works 40004-K01HC 10-12 Suzuki RM-Z 250 250cc Standard Bore High Compression Cylinder Kit 13.8:1 Comp.Cylinder Works 40004 K01HC 10 12 Suzuki RM Z 250 250cc Standard Bore High Compression Cylinder Kit 13. 8: 1 Comp. Description Cylinder Works Standard Bore High Compression Cylinder Kit Fits Models RM Z 250 (10 12) Specs Uses Vertex #23565 Compression Ratio13. 8: 1 Cylinder Diameter77 mm Cylinder Kit Type: Standard Bore High Compression Displacement: 250 cc Engine Type: 4 Cycle Includes: Cylinder, Piston Kit, and Top End Gasket Kit