A basic summary of oil standards and standards setting bodies.
The problem with the standards is that as they are updated they do not always provide backward compatibility for older engines. Only the Japanese standard JASO has continued specific support for motorcycles and wet clutches.
It is the JASO MA STD which is the most relevant standard for a motorcycle with a wet clutch.
Two classifiaction systems "S" for spark ignition (petrol) engines and "C" for compression (Diesel)
The API oil classification structure has eliminated specific support for wet-clutch motorcycle applications. The last API standards with wet clutch support were SF/SG/SH.
API SJ and newer oils are referred to be specific to automobile and light truck use.
The combined American and Japanese automobile associations standards group
Five specifications, GF 1, GF 2, GF 3, GF 4, and GF 5. No motorcycle specific standards.
It is the successor of the CCMC manufacturers committee (French: Comite des Constructeurs du Marche Commun). ACEA Standard A3 is the closest equivalent to the old CCMC STDs G4, G5.
No motorcycle specific standards.
JASO add motorcycle specific testing and standards to the existing international standards.
JASO have three classification systems, two stroke petrol, four stroke petrol and diesel engines.
JASO distinguish between wet clutch and non wet clutch oils with the MA and MB classifications.
Within the MA classification there are 3 classes, Generic MA, then MA1 and the strictest, MA2.
In order for a motor oil to meet JASO standards it must be at least of one of the following quality levels:
API SG, SH, SJ, SL, SM.
ACEA A1/B1, A3/B3, A3/B4, A5/B5, C2, C3.
ILSAC GF-1, GF-2, GF-3.
Then the motor oil's Dynamic Friction Characteristic Index (DFI), Static Friction Characteristic Index
Stop Time Index (STI) should be within the following limits according to the JASO T903:2011 friction test:
Dynamic Friction Characteristic Index (DFI)
Static Friction Characteristic Index (SFI)
Stop Time Index (STI)
≥0.5 & <1.30
≥0.5 & <1.25
≥0.5 & <1.45
≥1.30 & <2.5
≥1.25 & <2.5
≥1.45 & <2.5
≥1.30 & <1.85
≥1.25 & <1.70
≥1.45 & <1.85
≥1.85 & <2.5
≥1.70 & <2.5
≥1.85 & <2.5
The difference in friction characteristics are clearly seen in the differences between the MA and MB specifications.
JASO have lists of oils and the specifications they meet JASO Oil Lists