I did an experiment about a year ago, when driving i tried to not rev it over 3000 rpm. Boring i know and very frustrating but it did return 324 miles on a full tank. A word of warning thou don't drive it far once the fuel light comes on, it burns out the fuel pump and that's a tank off job.

Try it mate and post up what you get on a full tank.

Oh i do have a k & N on mine as well