gas tank overflowed while filling. thoughts?

[Guest]

Just started riding the 650e a few days ago. Filled it up for the second time yesterday. While at the pump, I filled it to an inch from the top, I turned to grab my gas cap from the top of the pump, and when I turned back, the gas rose and was at the top of the filler neck. As I looked at it it rose more and began overflowing. I scrambled for some paper towels....but of course they had none, The fuel rose out of the tank for about 20 seconds and covered the tank and dripped everywhere. It was honestly about 4-6 ounces that spilled out after it rose. It looked about like if I had spilled half a pop can onto the tank ( visual reference)
I had only ridden the bike 1 mile , from a cold start, to the corner filling station.
What would cause this?

Properly rebuilt carbs.
New petcock.
Stock pipes/air box.
Good carb boots in/ out sides

[Agemax]

you dont actually mention it, but when you stopped filling and turned to reach for the gas cap, was the pump nozzle still in the tank or had you removed it and hung it back on the pump?

[loud et]

No, I had stopped filling and the pump was hung up already.
So within the 10 seconds it took me to hang up the pump and grab my cap.....it had begun rising.
No bubbles or burping, just a full tank, slowly rising .

[kawfeedave]

Side stand, or center stand?

If it was leaned over, there's a chance that you the 'flow' of fuel into the tank allowed a high spot in the tank to take some fuel, and then once the flow into the tank stopped, the fuel found it's own level which happened to be above the filler hole. I guess the same thing could happen on the center stand, depending on the shape of the tank.

I'd say fill it to within 2" of the top next time, let it 'settle', and then trickle in the rest so the level can equalize as it fills.

[Agemax]

wow, i have never heard of that before........i have known it to drop slightly but never expand like that.
if the nozzle was still in the tank then it would be an obvious answer, but as it stands, I HAVE NO IDEA!

[sedelen]

I generally don't fill the tank quite so high, unless I'm going on a trip. Even still, I never had the gas rise in the tank after I put gas in it, or any of my bikes over the years. I always remove the nozzle from the tank and keep the bike upright before I go fumbling around with the gas cap.
If the gas was cold going into the tank and the warmth of the engine under the tank was enough to make it expand that might do it to some degree, but I don't think it would do it that quickly.

[loud et]

Hey Dave!
It was the side stand, but it was on the uphill side (sloping lot) so the bike was pretty vertical.
As you said, all I can do is fill it a bit less. The center stand would be a good idea too to assure even filling.

One other farfetched possibility is that the po had lined this tank. I don't know what they used.
It looks like a solid job. There was a few inches of fuel in it all winter with some stabil.
Possible delamination of lining or chemical reaction with the new gas.....not likely. But I will keep my eye on the liner too.

[Steve]

Sounds like you have a one-of-a-kind bike that does not consume gasoline, it generates it.

Personally, I would hang on to it, should get GREAT gas mileage on trips.

.

[tom203]

It's magic! don't let the oil companies find out, or your bike will vanish from the planet.

[loud et]

It's magic! don't let the oil companies find out, or your bike will vanish from the planet.

Better not vanish! I just started riding this one and I really like it!
I gotta say its so nice when you find one as I did with this 650 where not one single wire or anything has been touched....every single bit is exactly as it was when it left the factory.
No one had had their hands in this bike.

[chuck hahn]

I always fill on the side stand. Reason...when you fill on the center stand and then go to the side stand, the gas will rise in the neck. If its too full and you have a leaky gap seal youll have gas running down the tank almost instantly.

[loud et]

I always fill on the side stand. Reason...when you fill on the center stand and then go to the side stand, the gas will rise in the neck. If its too full and you have a leaky gap seal youll have gas running down the tank almost instantly.

Agree. I only fill like that If I am heading right off to put on some miles.

[chuck hahn]

I dont even do it then...I still have to take the bike off the center stand at the pump to get on. I never take that risk. That extra pint of gas isnt that critical to me.

[Gregory]

It's magic! don't let the oil companies find out, or your bike will vanish from the planet.

That is cool. When you start getting low on fuel, just remove the gas cap, turn around once, and put it back on. MUCH BETTER THAN PAYING $350 A GALLON.