I've never been a syntetic oil guy . I have tied Amsoil & Royal Purple in the past .
My normal bike oil's could not hang in my 990 .
So after some reading and discusion with engine builders I am runing Motul 15w50 .
I gotta say that already I have noticed with only 350 miles on this oil change - better smoother runing engine & better gas milage ! Now this is not a cheap oil BUT if I can keep the oil in longer than 1200 miles and with a 4 mpg increase I will atleast brake even !