When run my 19 SESG down to empty and the "miles to R" says 11 miles and I fuel up it only takes 5 gallons. Is there a way to calibrate the system?
It would be nice if they included a setting in the BCM to calibrate the fuel gauge, but if there is one on the late model bikes I've never heard of it. You could do a mechanical calibration by bending the rod for the fuel gauge sending unit, but it tends to be a trial and error method that requires a lot of patience. An error in the opposite direction, gauge reading higher than it should, is easier to fix with a little homemade electrical solution.
If you want to make the gauge read higher than it currently does, you would need to bend the float rod so the float is slightly lower. It's a good idea to leave a little cushion instead of trying to make the gauge exact. For instance, when the gauge says empty and the miles to empty display says zero, you want to have a little reserve of fuel still on board. When I did my old 5 gallon tank (actual capacity 5.4 gallons to the bottom of the filler neck), I set it up so I still have a .4 gallon reserve when the gauge shows empty. I don't have that much confidence in Harley's gauges, and since I had to push this overweight sucker to the gas station when it ran out of gas with the gauge showing 3/16 of a gallon remaining and the low fuel light still off (back when it was new), I wanted to make sure that wouldn't happen again.
Jerry