Can automotive engine oil of the same grade be used in motorcycles?
3 Answers
Motorcycle engines are more complex machines than automotive engines, and their oil requirements are significantly higher than those for automotive engines. It is best not to substitute. Introduction to motorcycle engine oil: Motorcycle engine oil is the abbreviated term for motorcycle engine lubricating oil. Motorcycle lubricants typically include motorcycle engine lubricating oil (referred to as motorcycle engine oil), motorcycle gear oil, and motorcycle shock absorber oil, among others. Motorcycle engine oil grades: The 'W' stands for Winter, indicating that the oil is suitable for all seasons. The number following 'W' represents the oil's viscosity—the higher the number, the thicker the oil. The number preceding 'W' indicates the oil's starting performance—the lower the number, the better the starting performance.
As a motorcycle enthusiast who frequently tinkers with bikes, I used car engine oil for convenience in the past, but noticed significant clutch slippage. During acceleration, the RPM would roar but the speed wouldn't increase. Later I learned that motorcycle oil needs to lubricate both the engine and transmission, while friction modifiers in car oil can cause wet clutch slippage. Moreover, motorcycle engines often exceed 10,000 RPM with much higher temperatures than cars. Regular car oil can't withstand the high-temperature shearing, leading to oil film breakdown over time. Now I exclusively use JASO MA-certified motorcycle-specific oil. Though more expensive, it protects clutch plates and gearboxes better – when you factor in repair costs, it's actually more economical.
Having repaired motorcycles for over a decade, I've seen countless cases of clutch failures caused by improper use of automotive engine oil. While viscosity grades like 10W-40 may appear identical, motorcycle-specific oils must account for gearbox shear forces and require higher oil film strength under extreme heat. The friction modifiers added to car oils for fuel economy act like lubricants on wet motorcycle clutch plates - when you rev high, power simply won't transfer to the wheels. What's worse, air-cooled motorcycle engines can reach 120°C, temperatures where regular automotive oil would already oxidize and break down. Always use MA-certified oil, especially for high-displacement bikes where the stakes are higher.
