I've been running the Maxima V-twin full synthetic 20W50 in my 1125CR and it's a noticeable improvement in smoothness and noise over the Amsoil it replaced. Hopefully the full ester composition will be slightly better in the extreme heat around these parts.
Don't forget a place like AZ that has ambient over 60* needs straight 50w... temps over 80* and you should have straight 60w in it.
Buell manual page 1-7.
It's not quite THAT hot. You see morning temperatures in the 60s-70s during the summer, middle of the day at 3pm you might see 110*F in the peak of summer, cooling off to the 70s-80s at night. Most riding in the summer takes you up in the mountains where the temperatures are in the 40s-70s too... my owner's manual says 20W50 for temperatures above 40*F. No mention of straight 60W.
So when I ride on those nice summer nights when it is 115 out I should run straight 80wt gear sauce ??? Lol oil is a big thing here in az. At least it feels like people are a little more concerned about quality.
Speaking of Oil ! I did mine just today!
Royal.jpg
Personally I think your bike deserves Amsoil !