Re: fuel gauge for bike
The best way without making a gauge (if you have a rear rack) is to simply bungee a spare jerry can (1 Gallon works alright for normal riding, 2 Gallon gives it a good enough range for serious riding). Just pull over and fill up when you run out. Also helps to make the premixing less irritating and lets drivers know they are not passing a bicycle.
Motorcycles, Motor-bicycles and bicycles- two wheels and the open air is all I need.