Air to fuel ratio is air to fuel ratio regardless of octane, so the answer is no. Using octane of too high a rating can cause incomplete combustion and reduced power output though.
Is this why valves appear more gunked up with engines that run high octane that don't need it?? It's just left-over crap that doesn't get burned??
I've began to run 89 in my bike full-time, and it doesn't complain....In fact, I've noticed it doesn't do the airbox "sneeze" when the throttle is cracked as often as it used to....I don't know if that has anything to do w/89 versus 93, but it's a possibility!!