As long as it doesn't ping, I use it. With the RK, (Carb) I stopped in just about any station and all good. In fact, in the winter I ran regular many times without any problems. Summer time, I run strictly premium fuel. Since I don't race or care about how fast I get off the light, it's not a big deal to me. In my Ugly bike I run premium all the time just because it runs hot anyway. Just my .02 worth.
Ugly John