How do you fill up your tank?

[BA80]

Well, I use the gas pump.

[canyon_jack]

mostly avoiding the $4.69 91 octane gallon at Grand Canyon

the most expensive in the whole state!

[natemoen]

the most expensive in the whole state!

SHOULD run fine on the lowest obtain. That's what it was designed to run on.

[fvincent]

Tank fill up

We were riding home with Bruce Gerken & Lady Bartender from Alex bay, (XSeast 2003) , and stopped for gas. Filled it right up on the center stand. We decided to take advantage of the picknic table near the pumps. I moved the bike over and put diown the kick stand. as we finished our break I looked over at the bike and the gas was streaming down the left side of my hot bike. The sun had come out as we rested , heated the tank enought to expand the gas to the point it took two large bath towels to suck it up. Made me very nervous. Never again. Fill it on the kickstand.


Floyd
'80G

[Bonz]

Correct me if I'm wrong here...

It isn't the gas expanding, per se, but whatever airspace in the tank does allow the air to expand from the heat of the engine especially when parked, or when the sun is hitting the tank. Liquids don't compress/expand much, if at all (physics) and air will expand (or gas vapors will expand), thus pushing the gas out of the filler on a hot bike. I believe as well, a properly working fuel cap vent will allow the air/vapor to escape to minimize or eliminate the issue as it relates to heak soaking a full tank and thus leaking out the filler.

Look at one of the magazine articles on this forum from back in the day, I believe the tester from the magazine even noted he got a wet thigh from gas coming out the top when he topped off.

I normally fill up the 80 SG Special on the centerstand, and with that said, I think most of what comes out the filler when I fill up with a hot engine is from the slosh effect of taking it off the centerstand (DUH, don't fill up to the brim, eh? I should learn... ), but I have had on occasion, the fuel seep out because of a full tank and hot engine and/or sunshine on the tank.

[cywelchjr]

Gas, like every other liquid or solid, contracts and expands with temp. This is why gas pumps must be calibrated for temp, because the amount of fuel is calibrated for a specific temp, and you will actually get a little less a a lower temp and and little more at a higher temp, with the same reading at the pump. This is by design and how it's supposed to work. A gas pump is considered accurate if it provides a measured gallon of gas at a specified temp (I believe it is 20c, but I'm not sure of that (this is the temp of the gas and the ambient temp)).

So, this nice cool gas comes up out of the tank, probably at 20 deg below air temp at least, and you put it in your tank and park in the sun with it over the hot engine at will over that temp and it rises 35 deg, it's gonna overflow.

This is the principle that liquid thermometers work on (some use alcohol, some use colored water etc depending on the temps their supposed to work at).

[Bonz]

Here's the data I found about gasoline, and the expansion as temp rises. I was under the impression that the expanding air in the tank was more the culprit, but take a look at this and figure we are dealing with 4 or 5 gallons of gas in terms of our tank capacity, and it corrects my incorrect logic.

"Because gasoline expands and contracts based on temperature, the industry uses a standard temperature -- 60 degrees Fahrenheit -- as part of its definition of a gallon. To the industry, a gallon of gasoline is the amount of fuel that occupies 231 cubic inches at 60 degrees.
But at 75 degrees, the same amount of fuel occupies 233.4 cubic inches. At 90 degrees, the gas expands to 235.8 cubic inches."

Good discussion!

[rover]

fill tank

I follow a Harley Dog till it breaks down, gets abandoned for a while. Then I siphon all his gas.

[ViperRon]

2 cents more.

Never had a fire situation myself but have seen it on a brand new tractor my friends father had. Comming home from 6 hours mowing his dad told him to go in the basement (A fool place to store gas) and get the gas can and fill the tractor to the top. Bill came out with the can and I helped hand it up to him and he proceded to fill it right to the top. It was a hot August day tractor was in the sun and the can came out of the basement of the house (they kept cool at about 70)can just a sweating. Bill my frind had to fill it right to the top. Five minutes latter his dad got on the tractor and tried to start it but it just cranked. Being the smart man he was the first thought was vapor-lock. So he took the gas cap loose spraying gas over himself and the tractor. It popped and sizzled and caught on fire while he ran for the hose. He lost hoses belts wiring paint but could have been burnt.

Cold gas pumped into a hot motorcycle tends to expand too ( expecially methanol enriched) so I tend to be real careful I like my paint hair and skin. I am sorry for the member that lost so much.

[Axel]

vigilant

I have to be very careful not to fill up too full as it always overflows if I do. I ruined a airbrush
job on my tank and when I got it repainted - I did it again . If I fill at midnight before I come home it expands in the sun the next day. I'm still trying to polish the marks out .

[SlipNot]

Usually depends on what type of vehicle I'm siphoning from!!!

[brownbear1000]

gassing up

i have a xs1000 and i sit on it not on a stans and use some papper towls over tank be couse i have a tooled leather cover i maid on my tank and gas will take the finish off of it

[Sol]

I just wanted to toss in my cents

I have a '80 MNS and we have high temps. It will leak, (but I thought it was my seal which does need replacement) so I give it some space at the top.
I never figured it was no never mind so I just went with what was easy: on the side stand.

A note on the center stand. I'm 5'9" and 145lb. I had no luck with the posted instructions I have seen, but I found a way. If you want another variation in method here is mine:
Left foot on the stand & get it leveled out with my left hand twords the front of the grab bar under the seat-ish & the right on the back of the grab bar. This puts my hip a little behind my back blinker. now I brace with my left foot and lean back, it might need a tug to start and ease off once it is past the top of it's arc. Basically, I can't get a good grip described in other methods positions and/or can't lift/push the thing enough to do the trick. Instead I put my body weight way out on a lever arm, the tug shifts it from rest and the new center of mass tips it over the center stand's pivot. Bingo, mechanical advantage! you can't just let the brutes push you around, no wait that's the fun part!