On my new-to-me Suzuki quad runner, it gives some indication of what oil to use in the owners manual, but just indicates SF or the similar (don't remember off-hand, but it's from 1994, so whatever was in spec back then). Nothing about motorcycle specific oil nor ATV specific oil. I haven't looked at a service manual yet but I'm assuming there is a clutch inside the oil? Casual surfing indicates that some are using motorcycle engine oil, others aren't. I'm not sure what is good vs best, and as an older machine I'm not finding a lot of info. If I dig through the manual and find that it's a dry clutch, then I'm guessing standard motor oil is ok; but if it's a wet clutch should I use something else? I've seen a mention about JASO-Msomething rating.