What do API and JASO mean?

API (American Petroleum Institute) Grades

A Double letter ‘API’ code classifies oils as suitable for different uses. The first letter of the API grade shows the type of engine an oil can be used in (either petrol or diesel). All petrol engines are classified ‘S’ which stands for ‘spark ignition engines’. All diesel engines are classified ‘C’ which stands for ‘compression ignition engines’.
The second letter of the API grade defines the quality of the oil. Ratings start with the letter ‘A’ (which is the lowest quality) and currently go up to the letter ‘J’ (which is currently the highest quality).

JASO (Japanese Automotive Standards Organization)

JASO 2 stroke Oils: In 1994, the Japanese Automotive Standards Organization (JASO), developed a set of standards for 2 stroke oils.
The standards were assigned according to a 2 stroke oils lubrication properties, detergents, initial torque (acceleration), exhaust smoke formation and exhaust system blocking (as 2 stroke oil burns, oil is deposited in the exhaust system, exhaust system blocking measures how much oil is deposited).
There are 3 classification grades for 2 stroke oils FA, FB and FC. The grade JASO FA is the lowest grade, assigned to oils which provide minimum performance characteristics and FC is the highest grade.

JASO 4 stroke Oils: In 1998, the Japanese Automotive Standards Organization (JASO), developed a set of standards for 4 stroke oils which were measured against an oils ability to resist clutch friction and slippage and to prevent wear and pitting in the gear box.
There are 2 classification grades for 4 stroke oils MA and MB.
The grade JASO MB is used for a lower friction oil and MA is relatively higher friction oil.
In 2006 JASO introduced the JASO MA2 standard. The MA2 standard was brought out for modern motorcycle engines.
The JASO MA2 standard is a higher standard then JASO MA and means the oil is suitable for use in bikes with catalytic converters in the exhausts.

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