I usually get between 300 to 350km per tank, the former is when I'm commuting via tollway and the later is when I commute within the city. The difference is the speed, when I commute via the tollway I'll be running WOT at some points, doing 100+ mph, braking hard when there is traffic and WOT again past the traffic. When I commute in the city I ride at much lower speeds.
When I go on weekend rides with my friends, all of them have sportbikes, I do push her a bit harder. Then I get around 250km per tank.
Yeah, I can get 400km per tank, but it is too damn boring. How do you ride?