A Study of Motorcycle Oils - Amsoil

There are six primary differences between motorcycle and automotive engine applications:

1. Operational Speed - Motorcycles tend to operate at engine speeds significantly higher than automobiles. This places additional stress on engine components, increasing the need for wear protection. It also subjects lubricating oils to higher loading and shear forces. Elevated operating RPMs also promote foaming, which can reduce an oil’s load-carrying ability and accelerate oxidation.

2. Compression Ratios - Motorcycles tend to operate with higher engine compression ratios than automobiles. Higher compression ratios place additional stress on engine components and increase engine operating temperatures. Higher demands are placed on the oil to reduce wear. Elevated operating temperatures also promote thermal degradation of the oil, reducing its life expectancy and increasing the formation of internal engine deposits.

3. Horsepower/ Displacement Density - Motorcycle engines produce nearly twice the horsepower per cubic inch of displacement of automobile engines. This exposes the lubricating oil to higher temperatures and stress.

4. Variable Engine Cooling - In general, automotive applications use a sophisticated water-cooling system to control engine operating temperature. Similar systems can be found in motorcycle applications, but other designs also exist. Many motorcycles are air-cooled or use a combination air/oil design. Though effective, they result in greater fluctuations in operating temperatures, particularly when motorcycles are operated in stop-and-go traffic. Elevated operating temperature promotes oxidation and causes oils to thin, reducing their load carrying ability.

5. Multiple Lubrication Functionality - In automotive applications, engine oils are required to lubricate only the engine. Other automotive assemblies, such as transmissions, have separate fluid reservoirs that contain a lubricant designed specifically for that component. The requirements of that fluid differ significantly from those of automotive engine oil. Many motorcycles have a common sump supplying oil to both the engine and transmission. In such cases, the oil is required to meet the needs of both the engine and the transmission gears. Many motorcycles also incorporate a frictional clutch within the transmission that uses the same oil.

6. Inactivity - Motorcycles are typically used less frequently than automobiles. Whereas automobiles are used on a daily basis, motorcycle use is usually periodic and in many cases seasonal. These extended periods of inactivity place additional stress on motorcycle oils. In these circumstances, rust and acid corrosion protection are of critical concern.It is apparent that motorcycle applications place a different set of requirements on lubricating oils. Motorcycle oils, therefore, must be formulated to address this unique set of high stress conditions.

To view an online narrated presentation of this study, click this link;
Amsoil - online Narrated Presentation; A Study of Motorcycle Oils

To download, view or print a .pdf of this whitepaper, click this link;
Amsoil - download PDF Presentation; A Study of Motorcycle Oils

To view the Amsoil link regarding this new test, click this link; On the Amsoil site; A Study of Motorcycle Oils