Found this here
http://www.motorcycleanchor.com/moto...to/mc_oil.html
API CLASS RATINGS APPLICABLE TO MOTORCYCLES:
SA through SE OBSOLETE -- Use SF/SG or SH unless you find motorcycle oil which still meets the original rating that your bike calls for in the owner's manual. I am not familiar with any SA/SB/SC/SD/SE rated oils still on the market, but there may be some available for special vintage class bikes (bikes built between 1910 and 1970).
SF & SG TECHNICALLY OBSOLETE FOR CARS, BUT STILL IN COMMON USE FOR MOTORCYCLE OILS -- You can find motorcycle oil which still meets the SF/SG rating (such as offerings from Castrol, Mobil, Royal Purple, Amsoil, Bellray, Motorex, Motul, Repsoil, etc). If your bike calls for that in the owner's manual, there are still a large number of motorcycle-specific motor oils on the market that are SF/SG rated, including every motorcycle oil which meets the full JASO-MA specification. Most current motorcycle engines still call for SF/SG rated motor oils. If you can not find an SF/SG rated oil and that is the rating called for, use an SH or SH+SJ rated oil -- but do not use API SJ, SL or SM!
SH Technically obsolete. This oil specification is used by some motorcycle manufacturers, and you can still find many SH rated motorcycle oils on the market. Do not use if your motorcycle calls for API SJ/SL/SM rated oils (only a few do).
SJ Technically obsolete. For 2001 and older automobile engines. An "Energy Conserving" motor oil (something good for late model cars, not most motorcycles). Note that this standard reduces the phosphorus contents of the motor oil, which is not necessarily a desirable reduction for most motorcycle engines. Check your motorcycle owner's manual specifically for recommendation of an SJ-rated motor oil before using it in your motorcycle, or stick to using SF/SG-rated, SH-rated or dual-rated (SH+SJ) motorcycle oils instead. Do not use unless an API SJ rating is specifically called for by your motorcycle manufacturer.
SL Technically obsolete. For 6/2001 - 11/2004 automobile engines. An "Energy Conserving" motor oil (something good for late model cars, not most motorcycles). Note that this standard reduces the ZDDP (zinc and phosphorus) additive contents of the motor oil even further than SJ rated motor oils, which is not a desirable reduction for most motorcycle engines. Check your motorcycle owner's manual specifically for recommendation of an SJ or SL rated motor oil before using an API SL rated oil in your motorcycle! Do not use unless an API SJ or API SL rating is specifically called for by your motorcycle manufacturer.
SM NEW/Current. For all 12/2004 and later automobile engines.
An "Energy Conserving" motor oil (something good for late model cars, not most motorcycles). The API increased the standards for anti-foaming, increased detergent levels, and improved low-temp performance, while lowering the ZDDP package contents again. API SM now replaces API SJ and API SL -- but SM-rated oil is still not suitable for most motorcycle engines (just as SJ and SL rated ones weren't), especially virtually every air-cooled, oil-cooled and air-oil cooled motorcycle engines and ANY motorcycle engine designed prior to 2001 (such as Suzuki Katana 600/750/1100, Suzuki Bandit 600/1100/1200). Check your motorcycle owner's manual specifically for recommendation of an SJ/SL/SM rated motor oil before using API SM rated oils in your motorcycle! Do not use unless an API SJ, SL or SM rating is specifically called for by your motorcycle manufacturer.