The following link is to the JASO list for all of the oils that currently meet the JASO MA specification. Using oils that are not JASO MA rated can lead to slipping starter clutches, and slipping transmission clutches, on wet clutch motorcycles. The use of friction modified (modern automotive) oils can lead to accelerated transmission wear. Modern automotive oils do not have the additives that are needed for transmission gears (or for cam over shim valve trains; primarily Zinc), because those additives damage catalytic converters. I think the link may be good even after the list is updated. PDF of JASO MA Oils Note: The list is long, and contains brands that are not sold in the U.S.A. More information on JASO: If the PDF link above does not work, the current PDF can be found on the JALSO website. Look for the letters MA in their link title. JALOS website (there are pages in english, but you have to look closely) JASO specifications explained (click through to the second page for more information) Note: There are oils that meet JASO MA specifications, but won't be on the JASO list because they did not seek (and pay for) certification, but did their own internal testing instead. Usually these olis will have "Meets JASO MA" somewhere on the bottle, instead of the JASO MA stamp. [EDIT] Some people have asked me about getting more specific information on motor oil composition. Most of what I know about oil has been gleaned from: http://www.bobistheoilguy.com The owner of the site has several technical write-ups about how oils are blended and tested. There is also information about having your used motor oil tested, which will provide you with a peek into what the internals of your engine are doing, and how well your chosen oil is performing. The results of these tests can help you dial in exactly how long you can run a particuar oil before needing to change it. [EDIT] Rotella T3 no longer exists. It was replaced by Rotella T Triple Protection, which has since been replaced by T4 Triple Protection. [EDIT] Many questions have come up recently about what weigh of oil to use. The viscocity choice has to do with the abient air temperature that you will be riding in. The charts below should guide your choice. The same information is in the service manuals and owner's manual for your machine.