Looks like I stopped reading too early on the Wiki writeup. Here's some more interesting reading.
JASO-MA
JASO is an acronym that stands for "The Japanese Automotive Standards Organization." Among other things, they set standards for oil to be used in motorcycles.
One standard, JASO-MA, specifies a set of characteristics an oil must meet to be certified by JASO. It includes such things as the amount of sulfated ash, the foaming tendency, and the degree of friction provided by the oil.
The friction test is what is of particular interest to motorcycles. An oil that provides too little friction has a tendency to allow wet clutches -- those bathed in the engine oil -- to slip. An oil that demonstrates too much friction does not provide the lubricity needed. The JASO-MA test specifies a range of friction the oil must fall within to meet the specification.
The new Rotella T CJ-4 15W-40 and 5W-40 packaging does not officially state compliance with JASO-MA.
However, posts in various motorcycle-related forums cite e-mail confirmation from Shell that Rotella 15W-40 and 5W-40 CJ-4 has been tested and shown to meet the JASO-MA friction test. The belief is that the new CJ-4 oil does in fact meet JASO-MA, but the packaging does not carry the certification, nor does Shell advertise it as complying with JASO-MA.
Testimonies from many motorcyclists on different forums confirm the applicability of Shell Rotella T as effective for motorcycles. Numerous "Used Oil Analysis" (UOA) on bobistheoilguy.com show acceptable wear metal numbers for Rotella T in motorcycles for oil change intervals from 1000 miles all the way to 8000 miles.
Speculation is that Shell focuses on Rotella's primary market of heavy duty trucking. Emphasizing a motorcycle certification might detract from the primary marketing. No confirmation or denial of that speculation has been offered by Shell.
It should be noted, however, that Shell Rotella's website does have a category in the "Ask the Expert" section that does mention Rotella usage in motorcycles.
I'll see if I can find out anything else, but if you ask me, this is the bargain way to get a high quality synthetic oil for your Busa. I'll try it next change unless someone comes up with a reason not to.
FWIW, my standard oil choice has been one quart Mobil 1 synthetic (the automobile kind) plus the balance of good conventional/dino oil (e.g., Castrol GTX). Been experimenting for years. Found that straight Mobil 1 was too thin for motorcycle engines which had trouble maintaining pressure at idle. Mixed with conventional oils, the Mobil 1 led to significantly fewer needed valve adjustments and the adjustments needed were fewer valves and less adjustment for each valve. This comes from the days of rockers and valve adjustments every 3000 miles. I'm going to try the Rotella synthetic next time.