Never have had mine run empty, best I got was about 220 miles before I filled up, had a bit left but it was getting rather low, I was loaded up doing about 70 mph most of the way.
Blatting over to Vienna on the motorways fuel consumption was very poor, but I was wringing it's neck fully loaded up with soft panniers, my zarges'top box', and stuff on top of that.
I was impressed with how the bike reveled in long distance fast mile munching, it was composed at cornering, side winds etc, and I was all but flat out for miles.