Originally Posted by clutchglass

The whole "Bearing Skate" myth is left over from the old days when Harley didn't sell a synthetic oil. Synthetic oil provides better cooling, is slower in breaking down, and has additive packages that surround carbon, and other impurities (thereby keeping them away from engine components on the way back to the filter). I also find it hard to believe the older bike wouldn't perform as well with synthetic oil.

I work in the refinery of a borax mine in the middle of the Mojave desert. We have done extensive testing in our reliability department on speed reducers (Gear Boxes) operating in a desert environment 24 hours a day...7 days a week. The plant is almost 100 years old, and some of our equipment is 30 years old or better. Almost every time synthetic turns out to be the answer. We do have a few places where backstops have to engage to prevent a conveyor from rolling backwards when the belt is turned off. In these situations we have to be careful about using a synthetic that has an anti-friction package as it can stop the backstop from engaging. So...in rare instances in industry friction modifiers can cause issues with equipment. As far as the "bearing skate"....when we have an equipment failure there is a tap root analysis performed to determine why...never has it been an issue with bearing skate. I even asked a trebologist (oil scientist) about bearing skate, and was told it was a farce harley invented...when they didn't succeed in boosting oil sales...they decided to start selling synthetic themselves. Now the claim made by them is that their synthetic is specially engineered for "harley engines"....as if they are made out of some special "unicorn horn" that other engines aren't made of.
My 2 cents is for you to go to several new car dealerships and raise the hood on a porche, corvette, turbo Cadillac, and many other high performance engines. Chances are you'll see one thing in common with the big money/high performance engines....they will all say use only mobil1 on the oil filler cap.
-clutch-
P.S. No matter if it's synthetic, or conventional oil you decide upon...use the same brand at every oil change. Switching back and forth between brands can cause issues with your engine sludging up....and especially on an air cooled motor....that's a bad thing.