One Post:
I know the rules say you can not run automotive oils in a wet clutch because of the friction modifiers. However, I have encountered a growing number of people who use some form of 10w30 or 0w30 in 600cc and 1,000cc sport bikes and even ATVs. Is the whole notion that automotive oils cause clutch slippage real? You read stories about how somebody walked to close to their ATV or motorcycle with a bottle of non JASO-MA oil and the mere presence of the oil in the same garage caused the clutch to slip. Then you read posts where somebody has been running non JASO-MA oil(s) for tens of thousands of miles with no issues.
Another Post:
I've been using automotive oils in wet clutches since 1977 and have never had any clutch slipage or problems.
Post from a real expert, not a shadetree mechanic:
Technically speaking Energy Conserving oil can not defeat a
wet clutch in good working order... whats confusing the issue
is the fact that all motorcycle wet clutches will reach a
point in their life and start to slip... no one complains
about clutch slip when new... but on about the 27K range is
when containments may build up to point where the clutch
begins to loose its grip during WFO (Wide Fooking
Open)throttle only... in error you can blame the oil but its
really the clutch...
I've been using 10/30 Energy Conserving Mobil 1 since 98 in
Mr.RC45 with no clutch slipping due to oil being certified
10% slipperier than non EC oil... and it's a bike with a tall
first gear good for 90mph that's known to incinerate clutch
plates..
Can synthetic oils cause my clutch to slip?
"To answer this in one word: No. Clutch slippage is caused by
many things, but the use of synthetic oil alone is usually
not the culprit. The truth is that some bikes seem to suffer
clutch slippage no matter what oil goes in them, while others
run fine with any oil. This is most likely caused by factors
other than the oil, such as the spring pressure, age and
clutch plate materials".