Running mobil v twin here. I did an extensive search and found a website with a resident guru who is apparently in the oil biz and has done a lot of research and testing of oils. V twin was his recommendation. After reading a lot of posts there i came to believe this guy knew what he was talking about from real experience. Most opinions on oil are just that, but this guy seemed to know from much lab research. So thats my oil of choice. Don't ask me to link the site, as i can't recall what it's called and only found it after searching google for a few weeks when i first got the bike.I doubt i could find it again very easily.