Model: 139QMB (for 50cc) Engine type: single, air-cooled, 4-stroke Bore x stroke: 39.0 x 41.4mm Displacement: 49.5cc Compression ratio: 10.5:1 Max. power: 2.0kW/7,000rpm Max. torque: 3.1N.m/6,500rpm Start: electric/kick start Fuel grade: RQ90 Oil grade: SAE15W/40 Lubricating system: pressure splash Clutch type: automatic, centrifugal Ignition: CDI