The other day I got to ride again for a bit. I filled with gas and checked the mileage. It came out to 50.077 mpg. That tank was mostly highway speed and 93 octane. The previous tank I checked came out to 49.745 mpg and it also was 93 octane. That tank was mostly 40 mph on windy hilly roads. I think the manual calls for an octane rating of 89 or more but I'm not certain, I'll have to check.
It's been several years since I have had a road bike but I enjoyed the fuel savings along with the ride. Is 50 mpg about the average for these road bikes? Yamaha star 950.