160-180 miles, it's time to take a break anyway. I used to think the same thing about my fuel gauge on my '08 EG, but decided like some others that I'd rather fuel early, than push late.

 

I had the same problem with my roadking. I found that the float arm for the fuel sender was rubbing inside the gas tank (hanging up). A slight bend in the arm was all it took to fix it. Modern day fuel senders are very cheaplly made potentiometers (variable resistors) attached to a wire arm with a float on the end.
If the resistance on the sender is corrrect sometimes all it takes to fix a inaccuate fuel gauge is a bend in the arm.
If the gauge never goes below 1/4 the float or arm may be rubbing on something inside the tank or may need to be bent UP to allow the sender more range of motion in the downward direction.

 

On my '08 the light comes on and it shows empty with about a gallon left. It is very consistant over the last 6000 miles. I fill up at 200 miles and take about 5 gallons.