Well, with a stock '81/H, stock BS34's with 135 mains, EMGO 27" mufflers, paper filters, 30 PSI in the tires, 33 tooth rear sprocket, moderate temperatures, windshield, 190 lb rider, PAMCO ignition, Iridium spark plugs, 89 Octane, average 55 MPH highway riding with a 30 mile out and in ride (60 miles total) with a few stops I managed 65 MPG.