I have found Gulf Premium gives the best MPG and power.
Next is Exxon super and then Sunoco super.
Iridium spark plug and synthetic purple oil seems to quiet the engine and along with careful trial and error of tire pressure and the use of Dynabeads to balance tires. All seem to work together for a great ride.
MPG avg is 80-100, top spead flat road is 58-62, highway downhill 76, 79 when riding the draft of a truck (all sppeds after realcuating the speedometer that is off by 6-8 MPH).
My weight is 170, plus about 20lbs of gear.