JASO Specifications
Historically, 4-stroke engine oils were indicated for cars and motorcycles. Based on the standards of the American Petroleum Institute (API).
When the service level was increased to API SH, which incorporated a friction modifier, these oils created a premature clutch wear problem.
At the same time, engine oils for passenger cars are not designed for higher specific power, high revs, integral gearboxes and oil-immersed clutches.
In 1998, Japanese Motorcycle Manufacturers (Japanese Automotive Standards Organization) established the JASO T903 MB, MA and MA2 Standards for 4-stroke motorcycle engines. The last version of the JASO T903 specifications is the 2016 version however.
| JASO MA2 |
|---|
Non-slipping oil Special friction modifiers or non-friction modifiers High friction applications High additive system Excellent protection against micro-pitting of gears and clutch slip system |
| JASO MA |
|---|
Non-slipping oil Special friction modifiers or non-friction modifiers High friction applications Low additive system Protection against micro-pitting of gears and clutch slip system |
| JASO MB |
|---|
Slipping oil Lubricants with friction modifiers Low friction applications |
As JASO Specifications were established for 4-Strokes motorcycle engine oils, in 1990 JASO M345 specifications were previously established for 2-Strokes motorcycle engine oils.
The next chart shows the standard indices for these specifications.
| JASO | Lubricity | Initial Torque | Exhaust Smoke | Exhaust System blocking | Detergency |
|---|---|---|---|---|---|
| FB | 103 | 98 | 45 | 45 | 65 |
| FC | 103 | 98 | 85 | 90 | 95 |
| FD | 103 | 98 | 85 | 90 | 110 |
In addition to the above engine tests, three standard physico-chemical properties indicated in the next chart are specified.
| Item | Performance classification | Limit | ASTM Test Method |
|---|---|---|---|
| Kinematic viscosity at 100ºC (mm2/s) | FB, FC, FD | 6.5 min | D445 |
| Flash point (ºC) | FB, FC, FD | 70 min. | D83 |
| Sulfated Ash mass (%) | FB, FC | 0.25 max. | D874 |
| FD | 0.18 max. |