Model NO.: HL- 173F /177F / 182F / 188F Displacement: 242 / 270 / 337 /389 Ml Small Gas 4-Stroke Engine Carburetor: Float Carburetor Cylinder Diameter: 73 / 77 / 82 / 88 Mm Piston Stroke: 58 / 64mm Compression Ratio: 8.2:1 / 8.0:1