I seem to recall my naked gs1000 getting 54mpg (us) on the hiway.
So 74mpg is the number to beat so far, too easy
(just kidding, looks to be something of a wall at 70mpg ish for bikes that can use the hiway) I just filled up the 250 this morning and have to approximate (switched tanks), but it is looking like 62mpg with learning how to ride again, and the stock sprocket.