My most recent fuel-up gave me 5.8L/100Km or just over 40MPG US. I filled up with 249km on the trip odometer and the tank accepted 14.55L of fuel. That means I still had 4L reserve and could have easily passed 300Kms.
That's not riding it slow either.
On Sunday Jessica and I participated in the "Motorcycle Awareness Ride". Without saying much about the ride (there isn't much to talk about TBH) I will say that we did 110Kms 2-up at a very relaxed cruise well within the speed limits... We started with a full tank and the first bar (of 7) on the digital fuel gauge didn't go off until over 100Kms. Usually it takes about 60. The soft power delivery of the VFR below 5500RPM makes for nice smooth 2-up riding.
As an aside, I'm hoping DynoJet or Bazzaz come up with a throttle mapping device for the VFR so I could tune it to deliver full power all the time. I'd still want to use the stock map for riding in the inner city or with a passenger so a switch to change maps would be cool.