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- ViscositySpecifications
Buy 10W-50 engine oil
10W-50 is above all a motorcycle grade: high oil temperatures, air-cooled or high-revving engines and a wet clutch running in the same oil circuit. In cars it appears in thermally heavily loaded sports engines. On a motorcycle, go by JASO MA2, not by the viscosity alone.
Why motorcycles need their own oils
On most motorcycles the engine oil also lubricates the gearbox and the wet clutch. Friction modifiers, of the kind modern car oils contain, make the clutch slip - which is why the **JASO MA2** classification exists, ruling exactly that out.
A car oil of the same viscosity is therefore no substitute. If the container says only ACEA and API, without JASO MA2, it does not belong in a motorcycle with a wet clutch. Conversely, the high high-temperature viscosity is the reason for the 50: air-cooled engines reach oil temperatures at which a 30 or 40 grade would be too thin.
In cars
There, 10W-50 is a fringe grade for engines under very high thermal load, often with the same reasoning as 10W-60: heat and bearing load. Where the manufacturer names 5W-40 or 5W-50, stay with it - the poorer cold start of the 10W is not an advantage you buy voluntarily.
Oil changes on a motorcycle
Two differences from a car. The intervals are shorter, often by operating hours or by season rather than by distance, and the fill quantities are small - 2 to 4 litres, so a 4-litre unit or a set of single bottles usually covers it. And on many models the oil level is measured at a standstill, upright and with the engine warm; measured on the side stand it is systematically wrong.
Frequently asked questions
Can I put car oil in my motorcycle?
Only with a JASO MA2 approval. Car oils contain friction modifiers that make a wet clutch slip - the viscosity alone says nothing about that.
What is the difference between 10W-50 and 10W-60?
Only the high-temperature viscosity: 10W-60 is even more load-bearing at operating temperature and intended for engines that explicitly call for it. At cold start the two behave the same.
Is 10W-50 also suitable for air-cooled engines?
It is a usual choice for exactly that, because air-cooled engines reach high oil temperatures. What is decisive remains the engine manufacturer's specification, on motorcycles together with JASO MA2.
