Why Motorcycle Oils are Different
The demands placed on motorcycle engine oils are more severe than those placed on automotive engine oils. Most motorcycle operators do not recognize what these differences are and to what degree they alter lubrication requirements.
1) Operational Speed: Motorcycles tend to operate at engine speeds significantly higher than automobiles. This subjects lubricating oil to higher loading and shear forces. Elevated RPM’s also promote foaming, which accelerates oxidation and reduces the oil’s load-carrying ability.
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.
3) Horse Power: Motorcycle engines produce nearly twice the horsepower per cubic inch of displacement of automobile engines. This exposes the oil to higher temperatures and stress.
4) Variable Engine Cooling: Automobiles use a water-cooling system to control engine temperatures. Many motorcycles are air-cooled or use a combination of air/oil design. This results in elevated operating temperatures, which promotes oxidation and causes oil to thin.
5) Multiple Lubrication Functionality: In automobiles, engine oil is only required to lubricate the engine. Many motorcycles have common sumps for the engine and transmission. 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. These extended periods of inactivity put more stress on the oil. Critical concerns are rust and corrosion protection.
When considering a motorcycle oil, consider the following criteria to determine the best for your needs.
1) An oil’s ability to meet the required viscosity grade of an application.
2) An oil’s ability to maintain a consistent viscosity when exposed to changes in temperature.
3) An oil’s ability to retain it’s viscosity during use.
4) An oil’s ability to resist shearing forces and maintain its viscosity at elevated tempartures.
5) An oil’s zinc content.
6)An oil’s ability to minimize general wear.
7) An oil’s ability to minimize gear wear.
8 ) An oil’s ability to minimize deterioration when exposed to elevated temperatures.
9) An oil’s ability to resist volatilization when exposed to elevated temperatures.
10) An oil’s ability to maintain engine cleanliness and control acid corrosion.
11) An oil’s ability to resist foaming.
12) An oil’s ability to control rust corrosion.
The complete Motorcycle Oil Study compares the differences between 28 of the most popular motorcycle oils, and shows the one that you should be using.
(PDF file, 2.44 mb)
