It is a very good idea to keep a log of your mileage and the amount of gas you put in each time you fill it up. That will give you a number that seems like a "safe" distance you can travel between fill ups. Of course none of this is a guarantee if you push the limit and try to make it to that next exit before filling up when it has already started to sputter on the turns and quick stops!!
One good idea is to carry a one gallon tank of gas with you next time you are getting low, and run the bike around somewhere safe until it does actually run out of gas. Then put the gallon in the tank and run over to the nearest gas station to fill it up. The total you buy plus your gallon is about all your tank will hold. Last time I filled up, I put 5.287 gallons in my 5 gal tank and it wasn't all the way empty yet. So the latter is a relative number only.
TQ
