I noticed a post in the Yahoo group that seems to warn that some of the new Shell Rottella Synthetic oil has a new certification, that being the letters "SM" and that at least one forum has noticed that this new grade seems to be causing clutch slippage in wet clutch applications just like the ones seen from using "Energy Conserving" type oils.
SM is in fact a not only a new designation in testing, but is an oil with a different formula than SL rated oils. It was appearently made to cause less problems with catalytic converters, so it is quite possible that it may also effect wet clutches, Read your bottles carefully and try to avoid buying some by mistake........
UPDATE JULY 1ST FROM KRUSTY'S POST @ YAHOO:
Cut and paste from google search results =
Motor Oil Guide
For all automotive engines presently in use.
Introduced November 30, 2004.
SM oils are designed to provide improved oxidation resistance,
improved deposit protection, better wear protection,
and better low-temperature performance over the life of the oil.
Some SM oils may also meet the latest ILSAC specification
and/or qualify as Energy Conserving.
Road Track Tech Tidbits:
By the way, an API SM motor oil is not compatible with most motorcycles, where
the wet clutch runs in a bath of crankcase
oil. I spoke with API about this and learned that it's an inherent tradeoff of
friction modifiers: These additives help fuel economy of cars; they're counter
to the needs of motorcycle clutches transmitting increasingly great gobs of
horsepower and torque. My API source said the best oils for motorcycles are
those meeting SJ and earlier standards no longer certified by API. Such oils are
typically obtained directly through cycle manufacturer channels.
Last edited by Knifemaker; 07-01-2009 at 09:08 PM.