When I gas up the amount I can put in varies because of the peculiar design of the tank (I think its a bladder). Anyway, I always fill up when I get down to one bar. When I fill, I let the pump automatically shut off, then I do a little manipulation of the hose sleeve thingy on the pump, like I do when I fill my motor scooter tank (I have to pull on the sleeve to get it to discharge fuel). I can usually get about a half gallon extra this way without accidentally overfilling, which I did once and which resulted in gasoline spewing out of the tank like a busted artery. I almost always achieve about 500 miles per tank, plus or minus a few miles. Also I notice that when I fill at one bar, I usually can put about 9 to 9.5 gallons in, but not more than that.