Bill, don't get confused. I never put Mobile 1 SM or SN car oil into a motorcycle like you just recommended (then retracted) -- ever.
I did put some Extended Grade Mobil 1 (SL spec'd) 0w50 into my Savage when it was a puppy (before JASO ratings and motorcycle oils became commonplace) and I ran it for five quick normal Suzuki oil change intervals until Mobil screwed their oil all up with the SM changeover (historical fact -- see BITOG) and I went over to Rotella T Full Synthetic (soon to become Rotella T6).
Metal produced by my engine during this Mobile 1 use period was greater than the amount of metal produced later on by Rotella (even though I quickly began extending the drain interval on the Rotella Synthetic to a full year and in that same time period I began to run the snot out of the engine with the new hot stage 2 cam).
Please note: newer engines likely do make more metal than well seasoned older engines -- I believe this and point it out to you now for consideration.So, when I say Rotella T6 is "better oil than Mobil 1" well, I have an empirical & reasonable reason to say that. Not to mention what BITOG says, or anybody else says.
As always, I offer data and pictures when I say something -- so here is my source material:
http://suzukisavage.com/cgi-bin/YaBB.pl?num=1197231468/0MOBIL 1 0w50 FULL SYNTHETIC oil, 1 year 5 oil changes (suzuki recommended intervals) ====================
ROTELLA T6 5w40 FULL SYNTHETIC oil, 1 year, same oil for a year (no changes) And I have never never thrown my oil under the bus in a fit of forgetfulness