Not sure if this info helps, but here you go.... My 2000 Road Star (1602cc) gas gauge shows empty and the low gas icon flashes constantly. I've run one can of SeaFoam thru the tank. I have put close to 800 miles on her with that happening.
At the end of May, I'll be going on a 1400+ mile trip. Using the trip odo, I know I can go 150 miles before having to switch over to the reserve.
No matter what you ride. Just ride!