My '06 SV650n (F.I.) with a +1T countershaft sprocket and a slip-on muffler gets about 55 MPG in town or on the hwy, but most hwy cruising is between 65 and 75 MPH. I haven't had a chance to get any numbers at lower speeds, but I think it would do a lot better around 60 MPH - probably 60 MPG or more.
Jay