Pterodactyl said:You may very well be correct. Ultimately we tend to focus on the wrong question in oil threads. Instead of asking, "What is the oil I should use?", we should ask, "What oil should I not use?" Assuming a rider selects an oil that meets the specifications provided by the bike manufacturer, then it would be hard to find a brand of oil (dino, blend or synthetic) that will not perform well.
And that really is the bottom line. While we know by vast experience that numerous oils will do just fine, properly the oils to not use are properly those which do not meet the MA requirements of Yamaha for these engines. I have three jugs of Rotella T6 in the garage and plan to use them when needed. They are marked MA, are fully synthetic, and I have no qualms about using them.
Beyond that, it doesn't matter how much you pay or what you think, your warranty is void if you don't use an MA oil. btw - it's easy to see what you used by doing some chemical tests of leftover oil or deposits if your engine blows up. That said, I've run Mobil1 and numerous other oils of all types, and am sure that at some point will again.