This thread has caught my attention for sure, so here is my two cent story...I tried Amzoil about two years ago on my 07 Ultra with my new HQ 103ci. Now let me say this first, no grass grows under my bike. My riding style is quick (I don't dolly-op when pulling an intersection, rain is a challenge not an inconvenience), smooth (I keep my head up and look through the turns), and defensive (I trust no one-thing/person or intersection), I am aggressive in all three categories. My Amzoil 20-50w experience came one day when engine noise was growing and diagnosed by me as a lifter was starting to collapse along with top-end excessive noise...it came on quickly and stuck around. So I changed the oil to straight 50w HD dino oil. The lifter noise slowly went away along with top end rattle but I had pinging unless I stayed at a higher RPM (2600 and up) at 10-20% throttle. I have since went in and changed my map to add fuel at 10-20% throttle and at idle with very little effect to my fuel mileage, I am leaving this Thursday for AZ, ME, UT, CO, SD with a fresh batch of Amzoil 20-50 (crank), Amzoil 85-110 severe gear (trans), ATF (primary), Amzoil 5wt (forks) and a fresh batch of HD Dot 4 Brake fluid front and rear. As of about 400 miles on these new fluids the "Old Stead" is running and sounding superb. It would not surprise me one bit if lifter and top-end noise starts to return, if this happens I will change out while on the trip to 20-50 Syn3 and go from there.