Gl-4 is gentler on the brassy bits. Add a generous dollop of the Lucas Oil Zinc Additive into the crankcase AND tranny! I've heard, that runnin' the flat tappets on the cam using oil without enough zinc ,is like running it without oil. It'll destroy the lifters and cam. I ran out of Marvel Mystery Oil. Bike was runnin' rough. Throw some in the tank on the next fillup. It'll restore your top end!
If I may add my contribution........HOLY F'ing shit, put some oil in your bike, and 3,000miles or so later take it out, and put some new stuff in. It does not matter what you run. If you change your oil regularly, your bike will last near forever!
I blame global warming, it makes my bike run hotter even when it's cold outside, so I am forced to obsess over oil additives I don't understand. Also, I use my bike to club baby seals to death, and that calls for some moly additive in the final drive....like a Guzzi uses. My $.02