Mobil Super 2T

Worth knowing

Under the JASO M345 standard, class FB is the baseline level of two-stroke oil. Its lubricity minimum is the same as for FC and FD; what separates the classes are the requirements for smoke, exhaust blocking and piston cleanliness: the minimum smoke index for FB is almost half that of FC and FD. ISO-L-EGB builds on the Japanese classes but adds a separate rating of piston skirt cleanliness, so FB and EGB are close in purpose but not identical.

This mineral oil’s typical values clear the limits shared by FB, FC and FD with room to spare: 8.7 mm²/s at 100 °C against a minimum of 6.5, and a flash point of 132 °C against a minimum of 70 °C. The sulphated ash of 0.05 % is likewise far from the FB limit of 0.25 %. Smoke, however, cannot be read from the data sheet: JASO rates it in an engine test. A scooter or chain saw whose manual calls for FC, FD or ISO-L-EGD needs a different oil; Mobil claims these classes, for example, for Mobil Extra 2T. A separate article tabulates the FB, FC and FD minimums and the difference between the JASO and ISO classes.