Cylinder: Single cylinder; Stroke: 2-stroke; Bore: 44 mm; Displacement: 49 cc; Chain: 25H; Gearbox reduction: 3.1:1 49cc 2-stroke engine: Air cooled racing engine capable of up to 40 mph depending on rider weight and terrain. Low fuel consumption: Uses a 25:1 oil to gasoline mixing ratio (gasoline to two-stroke oil) to reduce refueling frequency and improve efficiency. High performance kit: Includes high performance cylinder head, spark plug, powder coated metal pull start, air filter, and 14 mm carburetor; balanced crank and flywheel; ported piston windows; upgraded CVT transmission unit. Use scenarios: - Upgrade a mini bike or pocket bike to improve speed and torque for light off-road trails or neighborhood riding. - Replace or upgrade a compatible 49cc two-stroke mini bike to extend life and boost performance. - Build or refresh a small off-road or hobby vehicle using a compatible mini bike chassis.