I personally love the Shell Rotella T 5w-40 syn. I run it in every vehicle I own (XJ w/145k, Civic w/85k, Del Sol w/129k, and a Suzi 750 V-Twin with 26k). I started out with it just in my bike, because I had read it was great for wet clutches... It is. No slippage in a bike (and I do like to...