Over filling the fuel tank?

We aren't talking liters of extra fuel, more like a couple of ounces at best. I fill it to the ring that has the holes and then drive 3 miles to home. Never have had any problem with overflowing or expansion due to heat.

I overfill my tank on canyon rides when we may be a hundred miles or more between gas stations. I don't necessarily jam pack it with fuel but I'll attempt to get it far enough up where the level stays at the bottom of the filler. That still allows an air pocket at the top of the tank.

As long as you ride it and don't let it sit in the sun or trailer it then have a big change in elevation, shouldn't be an issue.

The guy in the video says he gets 38 MPG and that is UK Gallons, not US. 1 UK gallon is 4.54609 litres. In the video he manages to squeeze in an extra 1.53 litres of fuel when he brims it, so he is only getting an extra 12.79 miles per tank before having to fill up.

Now unless you know that extra 12-13 miles is going to be the difference between making it to a fuel station or having to push it, why bother? If you know you are in an area you can get fuel every few miles it's just a waste of time. I mean for a bike with a 17L tank (3.74 UK gallons) at 38 MPG he is getting 142 miles to the tank, let's call it 140 miles to the tank before it dies. This will only save you 1 extra fuel stop per 10 fuel stops! So to travel 1500 miles you stop 10 times instead of 11 times by adding that little extra to the tank.

Is there really any point when you look at it like that?

That's fk'n crazy. He absolutely appears to dump another 1.5 L.

Let's say he wasn't filling as high as he should to begin with, and maybe say you wouldn't top off to that extreme... You're theoretically squeezing another .75 L

Riding conservatively, that .75 should net you another 7 to 8 miles.

I overfill mine a little when touring, if I might need the extra range, but not all the way to the top. Probably about 1/2 of the neck, and never any overflow, even in hot weather. On bikes without a charcoal canister, you wouldn't ruin anything by overfilling. I've never heard of a gas tank gauge breaking before, and the guy from the video linked above already proved that theory wrong with his FZ-10, so no worries there . However, I'd only overfill the tank if you're going to use up the overfilled amount right away, especially in hot weather. By the time fuel heats up, it'd be already below the neck, so zero spill on the ground thru the vent. But if you overfill it and park it right away, it could not only stink your entire garage, but possibly create a fire hazard, so I wouldn't do that. The only part of overfilling I don't like is fuel splashing all over the tank. Not a big deal, but it annoys me. I can do that splash-free near my house, where one Shell pump is defective, and it keeps pumping fuel even submerged. I only use it on the bike though; it made a huge mess when it overflowed while I was cleaning the windshield of my truck.

Anyway, with my tank slightly overfilled, I could have gotten around 150 miles out of my tank at my 4K' of altitude, riding spiritedly in the twisties, and at a good clip on the straights. On that test trip, did 130 miles, and the reserve light just came on as I pulled into the gas station, hence my 150-mile estimation. It was actually better than I expected. I'm ready for a break after 120+ miles anyway. The only problem is in unfamiliar places. Since we don't know where a gas station will be, I err on the side of caution and stop sooner than I want to if in doubt. A small price to pay for such a fun machine .