Would I really see a wide variance due to tank expansion? If I park the bike on the side stand, and look into the tank to see where the fuel level is at the end of each fill up, I can't imagine the variance on a 2.9 l tank would be more than 50 ml/.015 gals. or so, even with tank expansion/contraction. And if I'm verifying the fuel level by sight each time, that seems like valid data to me. With which I can make some comparisons.You won't be able to accurately compare calculated consumption to how much petrol you put in the tank if you zero it every tank full, as it is impossible to accurately fill the tank to the same level each time due to the expansion portions of the tank. You will get a better reading if you keep track over 5-10 tank fills.
I have a phone app that allows me to enter all the fill up data in about 5 secs, so doing so after I hang up the gas hose is easy. And after 30 fill ups (not just 5-10), I'm starting to get a pretty good read on what my bike's mileage is in different conditions. Still haven't run it fully loaded all day at 70 mph into a headwind. But I'm sure that day will come. :laugh:
Yes, if you're trying to get from gas station to gas station out here in the empty parts of the western U.S. I can think of several routes out here where I'll have no choice but to carry spare fuel. Knowing how much fuel I've burned can prevent a very long walk.Does it really matter on a thumper? 😂