An oil for the double-stroke engine lives shortly and ends its lifetime in the exhaust pipe.
Compared to the four-stroke engines, these oils have far fewer additives; they do not contain viscosity and anti-foaming conditioners. On the other hand, they contain many detergents which keep the engine interior clean and pigments which make oil detectable in the mixture with gasoline. The base oils can be both mineral and synthetic. To get the effect of self-miscibility with gasoline, a solvent is added to the oil to provide it with a characteristic smell.
Oils for double-stroke engines are classified according to strictly defined quality standards. The most frequently used criteria are the API and JASO classifications. The API classes have been established by the American Petroleum Institute, mostly for passenger cars.
In case of motorcycle oils, it is better to follow the JASO certificates. JASO, or Japanese Automotive Standards Organization, are standards which have been specifically developed for four- and double-stroke motorcycle engines.
Qualitative classes for oils for double-stroke engines:
- API TA - Oils for older generation design double-stroke engines
- API TB - Oils for the contemporary design double-stroke engines operating under average loads
- API TC ~ Oils for contemporary double-stroke engines exposed to the highest loads
- API TD - Oils for sterndrive engines of motorboats
- API TE - improved TD class with better lubrication capability and biodegradability
- JASO FA - Oils for older generation design double-stroke engines
- J ASO FB - Oils for the contemporary design double-stroke engines operating under average loads
- JASO FC - Oils for the contemporary design double-stroke engines operating under high loads
- JASO FD - Oils with an increased content of detergents, based on JASO FC and intended for double-stroke engines
- L-EGB (corresponds to JASO FB)
- L-EGS (corresponds JASO FC)
- L-EGD (does not have a JASO equivalent)