YX W125 - Type: 4-stroke, air-cool, single cylinder, horizontal  
Bore × stroke: 52.4×57 
Total Displacement: 124ml - Compression Ratio: 8.8: 1 
Max.Net Power/rpm: 5KW/8000±500r/min 
Max. torque/rpm: 8.8N.m/5000±500r/min 
Min. Fuel Consumption: ≤ 367g/KW.h 
Ignition advance angle: BTDC 15º±2º 
Valve clearance: 0.05±0.02mm
Fuel Grade: 90# GB484-89 
Engine Oil Grade: SE: 15W/50 
Engine Oil Consumption Rate : ≤ 8g/KW.h 
Transmission Ratio: Primary: 3.722(18/67) 1gear: 3.272(11/36) 2gear: 1.937(16/31), 3gear: 1.350(20/27) 4gear: 1.043(23/24) 
Type of Spark plug: C7HSA
Gap of Spark plug: 0.6-0.7  
Ignition: C.D.I 
Clutch: multi-plate oil bath, Manual
Air Filter: Recommended Foam
Lubrication: pressure and splash
Engine Oil Capacity: 1.0L 
Starting: kick