The oil which consists of chemical compounds which are not originally present in crude oil or petroleum but were artificially made or synthesized from other compounds are called Synthetic Oil. Synthetic oil are mostly used as a substitute for petroleum or as a substitute for lubricating oil mostly in conventional motor oil refined from petroleum. A synthetic oil or synthetic fuel is used as a replacement for petroleum mainly because of a shortage of petroleum or because petroleum is too expensive. Synthetic oil made as a substitute for lubricant refined from petroleum generally provides superior mechanical and chemical properties than those found in traditional mineral oils or petroleum. Semi-synthetic oils are mixture of mineral oil with not more than 30% synthetic oil. The Semi-synthetic oils are designed to have all or most of the benefits of synthetic oil. The Semi-synthetic oil is less costly than the cost of pure oil. In 1996 MOTUL introduced the first semi-synthetic motor oil. Evidences show that conventional oil lacks the performance of synthetic oils in the low-temperature areas and high-temperature oxidation stability. Long and short chains of carbon and hydrogen atoms in an inconsistent mixture make conventional motor oil. In the extreme heat of an engine, short-chain molecules can disappear, while the unstable molecules can oxidize and break down. Conventional oils contain greater amounts of impurities in the form of sulfur, reactive and unstable hydrocarbons, and other contaminants that cannot be completely removed by conventional method of refining crude oil. It is advised not to mix semi-synthetic oil with other synthetic motor oils as that might reduce the efficiency of the vehicle. Semi-synthetic motor oils for motorbikes have been specifically optimized for applying in motorbikes. The semi-synthetic oils for the motorbikes include high class transmission clutch performance and high temperature operation like air-cooled operation. The high performance API SL, SJ and SH are multigrade motor oil provides high level of protection and performance in gasoline and diesel engines. The semi-synthetic oil prolongs the life of an engine. It has an effective anti-wear additive which enhances the performance of the engine and at the same time lowers the consumption of oil. Technically speaking semi-synthetic oil provides better chemical and shear stability. The semi-synthetic oil decreases evaporation and benefits the environment by creating less waste oil. However there are many disadvantages associated with semi-synthetic oil. The first and foremost disadvantage is that the initial cost is very high compared to the petroleum based oils. Over the years the use of semi-synthetic oils has increased the performances and power of the cars by almost 30%. Technological advancements have reduced oil consumption by up to 60%. There are various engines oils in the market to choose from to meet the requirements of the new generation cars. Given the environmental demands the modern motor oil be synthetic or semi-synthetic oils is required to do some extra than just lubricate and protect the engines. For more information on Semi-synthetic Oil visit www.car-maintenance.ucoz.com