Bikes generally lack even the rudimentary fuel level gages that do exist on our fancy riding lawnmowers.
A proper biker can keep track of his gas by resetting his trip odometer
(oops, we don't have one of those either).
Well, we have a reserve tank and a petcock to turn when it's time to use it. That's our official "gas gage".
We also know if we fill our Savage's up every weekend we can ride all week long on an around town basis without hitting reserve IF we fill the tank up every Saturday morning.
If we are going on a trip, fill it up before you leave and then stop every 100 miles and top it back up. (your aching butt and back are another reliable time/mileage indicator, as well as your need to get a cup of coffee and take a leak)
In short, even if you had one, what in the world would you ever need to look at it for?
Oldfeller