I have vacuum in the fuel line? Im confused.

[Tarbash 27]

I have a 1981 GS1100E I am trying to get running. I completely dissasembled the carbs and rebuilt them. There perfect so I think.

The fuel tank petcock works perfect also. Reserve, on, and prime work as they should.
Vacuum line from carb 2 to petcock is hooked up and works.

The bike runs fine, not jetting issues or anything, perfect.
I have a clear fuel line so I can see if gas is flowing, NO inline filter.

The problem, When the fuel line is hooked up to the carb and the tank, gas will only flow when the bike is running. Thats how is suppose to work. But when its on prime, gas will not flow out until the bike is running, its suppose to flow whether the bike is running or not. If I detach the fuel line from the petcock while on prime, then the gas will flow right out of the tank like its suppose too. There is no problem with the prime position. There is no problem with the gas cap, I had it off while doing this.

It seems like the carbs are not venting to let the gas in and there's an air tight seal preventing gas from flowing through the fuel line. It sounds confusing, but it is.
The problem seems to be in the carbs? Please help.

[Guest]

The float bowls are full and the float needle and seats are preventing the fuel from flowing.

[Tarbash 27]

I didnt even think of that, I must be thinking to hard.

But shouldnt the air thats in the fuel line rise and the fuel flow downward from the tank?

[bwringer]

Don't worry about the air in the fuel line. It's perfectly normal for some bubbles to just sort of sit there.

Put on some opaque fuel line if it bugs you that much.

[Tarbash 27]

No, the entire tube is dry from the petcock to the carbs.

[LarryA_Texas]

No, the entire tube is dry from the petcock to the carbs.

If you're still not sure try this: connect everything and then open the petcock to prime. While in prime remove one of the float bowl drain plugs from the bottom of the float bowl. Fuel should flow out of all 4 of them. If it doesn't you have a problem, probably with the float needles.

[Guest]

If it flows as soon as you disconnect it I would say it has to be a venting issue.

[bwringer]

Are the vent lines open to the air, as they should be?

[Tarbash 27]

Yes vent lines are open. Ill double check on them and try the drain plug thing to see if that does anything. It doesnt seem as if anything is bad with the petcock, but maybe Ill pull it out and have a look anyways.

[bucketsofgs1000]

Fuel cap vent?

Perhaps your fuel cap vent is clogged. Try running the bike with the cap off the tank and see if that changes your operation. If so, your vent is clogged in the cap. There is a small orifice and steel ball in the cap, take it apart, clean it, and re-assemble. It can easily become clogged with dirt. Good luck,

-Zack

[mighty13d]

[quote=Tarbash 27;980666] There is no problem with the prime position. There is no problem with the gas cap, I had it off while doing this.
.[/quote

[Tarbash 27]

I think I fixed the problem. I blew air through the vent tubes and then turned it on to prime and gas flowed right in like its suppose too. So it runs fine now, but my biggest problem is its not charging.