Wikipedia (Shell Rotella T):
Though marketed as an engine oil for diesel trucks, Rotella oil has found popularity with motorcyclists as well. The lack of "friction modifiers" in Rotella means they do not interfere with wet clutch operations. (This is called a "shared sump" design, which is unlike automobiles which maintain separate oil reservoirs - one for the engine and one for the transmission). Used oil analysis (UOA) reports on BobIsTheOilGuy.com have shown wear metals levels comparable to oils marketed as motorcycle-specific.
JASO-MAJASO is an acronym that stands for "The Japanese Automotive Standards Organization." Among other things, they set standards for oil to be used in motorcycles.
Shell Rotella T 15W-40 conventional oil now lists on its packaging JASO MA as one of the specifications it meets, as does the Rotella website product page:
Note that the 10W-30 conventional oil does not list JASO-MA.
The newer fully synthetic T6 5W-40 oil also lists JASO-MA compliance on its packaging and on the Rotella website.