Splitting hairs on this thread.

A 6 gal tank is gonna hold awful close to 6 gal. Good lord.
In my many years, I have seen a bike or two leak out the vent when parked, but that's rare. It ain't gonna happen at all ever, unless you fill it up and immediately park it, and leave it in the hot sun. If you are riding home after the fillup, you will burn off some fuel.

It's not rocket science. Either fill it to the brim, or don't. The capacity is not relevant.

 

Aw lighten up a little Ed . We've come a long way since the days of odometer only and then give her a shake or two to hear how much is left, maybe even go on reserve.

 

I always run mine down to 0 miles dte. It seems to always take the same 5.2-5.4 gals.

 

Wait a minute Ed. Depends on how far he lives from the gas station. He could only live a block or two away and, seeing how he lives in HA, it is definately warmer in his garage than the temp of the gas coming from an underground tank. In that scenario expansion is possible.

 

It is to some of us! Seems that so far nobody has established how much gas the tank actually holds or how far we can ride before we have to fill up. If you are riding long distances on tour in unknown places, being sure of your range is very useful information. This is worth pursuing further!

Another scenario is filling up while travelling and stopping for a break, when the heat of the engine or sun on a full tank of cool gas is very likely to cause over-flow. Avoiding that is something that comes with extended experience, just as knowing how much gas we can squeeze in there!

 

The fuel guages on my previous bike (FLTR) and current FLHTCU have been dead on accurate.

Hit's "Lo" that means there's a half gallon left (about 20 miles) Whenever I've filled 'em up right after hitting "Lo" it always takes 5 1/2 Gallons

Seems like a full 6 Gallon capacity to me,I always fill my tank as close to the top as possible.

 

On my RKC I filled up with 5.8 gals after running 40 miles with the fuel light on....went 252 miles on that tank.

 

Exactly.

How much fuel do the lines hold? Will an in line fuel filter extend your range?
If your riding in an unfamiliar area, how far is it to the next station? Will they have 91+ octane? Are you on a track calculating to see if you can make another 3 laps? Wanting to run out at the finish line for dramatic effect (just like in the movies).
Mine doesn't get exactly the same mileage on every ride. A strong wind, city driving, country roads or interstate driving?

If you don't know how much fuel was in your tank when you put in another 5.x gallons then you don't know how much gas is in the bike.
Can you put more gas in it than it was designed for (leaving less room for expansion)? Yes.
Is it possible to fill it on a cold day and have expansion cause overflow? Yes
Just get gas when it's convenient. If its a cool morning and you know it's going to warm up then don't top off the tank. Don't worry about how much the tank holds.

 

Best I've done is 261 miles, then could only get 5.35 gallons in on the side stand. That was mostly highway riding at 60 though.

 

I have run mine with the fuel light on, the DTE reading "lo" for 40 miles and still only put in 5.7 gals (after riding 260 or so).

What I have noticed is that the DTE countdown recalculates after each fill-up. That said, my lowest mileage on a tank was 194 (seriously strong headwind across the Navajo reservation last May). The highest mileage on a tank has been 314. I was definitely ready to stop, even with my Road Zeppelin seat!

I typically get 240 out of a tank before I re-fill with 5.2 - 5.3 gallons for most of my riding (mix of city/hwy and a little mountain riding)