Dohner, B., Michlberger, A., Castanien, C., Gajanayake, A. et al., "Improving Fuel Efficiency of Motorcycle Oils," SAE Int. J. Fuels Lubr. 6(3):1014-1020, 2013, doi:10.4271/2013-32-9063.
As the motorcycle market grows, the fuel efficiency of motorcycle oils is becoming an important issue due to concerns over the conservation of natural resources and the protection of the environment. Fuel efficient engine oils have been developed for passenger cars by moving to lower viscosity grades and formulating the additive package to reduce friction. Motorcycle oils, however, which operate in much higher temperature regimes, must also lubricate the transmission and the clutch, and provide gear protection. This makes their requirements fundamentally very different from passenger car oils. Developing fuel efficient motorcycle oils, therefore, can be a difficult challenge. Formulating to reduce friction may cause clutch slippage and reducing the viscosity grade in motorcycles must be done carefully due to the need for gear protection. Additionally, in high temperature motorcycle engines, low viscosity oils are more prone to oil consumption, which will negatively impact fuel economy. They also may cause more deposit formation, which can reduce overall performance.The lowest viscosity grade oil currently recommended by Honda for motorcycle applications is a 10W-30. This study describes the development of a new 5W-30 motorcycle oil to deliver enhanced fuel efficiency in motorcycle engines. The key target of this development was to deliver enhanced fuel efficiency with a 5W-30 while not compromising any of the performance of the current high quality 10W-30 oil. Testing was conducted to validate oil consumption, clutch performance, oxidation resistance, wear protection, gear protection, and engine cleanliness in modern Honda motorcycle engines. In all aspects, the newly developed 5W-30 oil performed equivalent to or better than the high quality 10W-30 reference oil. As the final proof of performance, the new 5W-30 oil was compared with the 10W-30 reference oil in a motored motorcycle engine friction torque test and clearly demonstrated the desired enhanced fuel efficiency.