My Fazer does 51 mpg trotting to work and back, mainly duel carriageway at between 70/90 mph. This gives over 200 tank range, the other sat I took her out and thrshed the knacks off of her and got 130 per tankful
I think BB's should/could be a little better on juice, they give similar power to my Fazer (130ish at rear wheel) are more aerodynamic and have fuel injection, which really should make it more efficient??
My first ride last week was 130 miles till bar flashing, yesterdays was a little better 148 till flashing. This is mainly back roads where you are on/off the throttle regularly, christ knows how low this will be if I give her some stick (pending)