About 43 to 60 mpg (U.S.) depending how I felt that day on the '14 CB1100 (5W40 synthetic, 10W40 semi-synthetic, and 10W30 GN4 - of course, any choice didn't matter).
Average about 47 mpg (U.S.).
During warm season riding 50F and higher. Drops off noticeably below freezing.
>>> Spring is an extension to the riding season. ¯\(ツ)/¯ <<<
so, all kidding aside, i filled up today as i rode the 1100 to work. over 4 tanks of fuel with: a powercommander, a flashed ecm, full exhaust and 1 tooth smaller on the front sprocket and typically fairly aggressive not old fart 45 mph putting in 6th, mostly riding in town. with a few 80mph + runs on the highway, i averaged 47.6 mpg. this is running castrol synthetic, (not that it matters).