All organic conola or authentic olive. Whichever is on sale. Occasionally ill cheap out and grab the generic margarine sticks.
But seriously. Any synthetic 20w50 oil will do the job and do it well. I use mobil 1 because it is readily available to me at any local autozone. Oil change every 2k miles and a full service/ tune-up, new filter oil screen etc etc, every other oil change for me on my 1125.