Can a Four-Stroke Motorcycle Use Car Engine Oil?
1 Answers
No. In car engines, the lubrication of the engine, transmission, and clutch is separate, with the oil temperature in the crankcase ranging between 75-90°C. Here are the reasons why car engine oil should not be used: 1. Different Structures. In car engines, the lubrication of the engine, transmission, and clutch is separate, with the oil temperature in the crankcase ranging between 75-90°C. However, in motorcycle engines, components such as the wet multi-plate clutch, high-speed and transmission gears, shift mechanism, piston, cylinder, intake and exhaust valves, and other moving parts are all housed within the same structure and share the same oil volume. Additionally, the friction plates of the clutch and the rotation of the transmission gears generate significant heat, causing the oil temperature in the crankcase to reach as high as 80-120°C. 2. Differences in Cooling Effects. Car engines typically hold about 5-7L of oil, while motorcycle engines only hold around 1L. Oil needs sufficient flow to effectively dissipate heat. The amount of oil significantly impacts cooling performance. Moreover, most motorcycles rely on air cooling, which is far less efficient than the radiator-based liquid cooling systems in cars. Even liquid-cooled motorcycles have smaller coolant capacities than cars, resulting in poorer heat dissipation. This inevitably leads to much higher oil temperatures in motorcycle engines compared to car engines. 3. Power per Liter. The power output per liter for cars is generally 60-80Kw/L, while for motorcycles, it is 100-120Kw/L—about 1.5 times higher than cars. In terms of power-to-volume ratio, motorcycles are twice as powerful as cars. Car engines typically operate at 3000-5000r/min, whereas motorcycle engines run at 8000-11000r/min, which is 50% to 120% higher. At maximum power output, motorcycle engines reach 10000-15000r/min, while car engines peak at 4000-5000r/min, rarely exceeding 6000r/min. 4. Engine Stress. Due to differing driving conditions and technical requirements, motorcycle engines endure 3-4 times higher stress levels than car engines. Motorcycles are lightweight and often operate at speeds corresponding to maximum power or torque output, leading to higher engine temperatures and greater wear. This demonstrates that motorcycles operate in much harsher conditions than cars.
