Easy to find out. Fill the tank, zero trip meter, Go for a ride. When the motor sputters, switch to reserve and note miles traveled. Now each time you fill up you zero the trip meter and start looking for a filling station when you reach the mile from that first ride.
For me I just look for gas station at 100 miles or so, reserve kicks in at about 110 miles and I plan to walk after 150 miles.
93 VT1100C Sleeper, VH Exhaust, Saddleman Seat, Baby Apes, Metzlers, 2mm sleeved and bored (1150cc),10.5:1 comp, Modified Heads, Valves, Cams, Adjustable Timing, Bored Carbs.