As well as a four-wheeled vehicle, in the field of motorcycle,
development of the CO₂ reduction technology and practical use are
required for global environment protection. Therefore the energy
conserving by engine oil is required. There are several
technologies which have been applied to the passenger car engine
oils using lower viscosity base oils and some friction modifier
additives.
However, these technologies might bring difficulties or problems
to apply to the motorcycle engine oils. Since motorcycles normally
have transmission gears and a wet clutch system inside the
crankcase, the gear lubricity and clutch friction performance are
additionally required for motorcycle engine oils.
Motorcycle engine oils are also used under severer conditions
than passenger car engine oils. Therefore, lower volatility
performance at higher temperature conditions, higher shear
stability, anti-wear performance and gear pitting toughness are
needed.
In this study, we report the results of motorcycle engine oil
performance evaluation with engine oils containing high quality
mineral base oils and specially selected polymers. The high quality
base oil contributed to reduce oil consumption, compared with the
current 10W-30 grade motorcycle engine oil. The moderate selection
of polymers can increase oil film thickness and also improve shear
stability. Additionally, actual motorcycle engine test was
conducted. The candidate oil showed better fuel saving and better
effect for gear fatigue and noise prevention.