Fuel overflowing from pod filters

[BT85]

Sorry if this has already been posted about..I've done a quick search and didn't find much.
I bought a GS450 from a friend awhile ago(not running, or wired)
I wired the bike, changed some stuff on the frame and reassembled it.
I've been trying to run it lately, but I'm having a problem. If i leave it sit overnight, and go to start it, it'll start up pretty easily. After running for about 1 minute or so, it starts to choke out and gas will overflow from the carbs. I have pod filters, straight pipes, and i rejetted with a 6Sigma jet kit. Anyone know why gas keeps overflowing? it runs great for a little then just takes a ****.
thanks in advance for any help

 

[bikemtn]

Pull off carbs, dissasemble, dip, new o-rings, and sync. This is the first thing you should do......

 

[bikemtn]

True tkent!

No, the first thing is replace the petcock. If it was working correctly there would be no fuel to spill.

 

[BT85]

i pulled the carbs prior and cleaned them pretty well. i understand that the petcock is vacuum activated. the fuel isnt spilling when the bike isnt running, it starts to spill when it is running, and then chokes it out. if i leave it sit for awhile it will start back up before just going to do the same thing

 

[tkent02]

I read your post better and deleted mine, it's only leaking when fuel should be flowing, so it's not the petcock.
Floats stuck? Floats set wrong? Bad O rings? Needle valves too worn out?

I would guess a float is caught under a poorly cut gasket or something like that not letting it rise up to shut off the flow..

 

[Thumper88]

The float could also be leaking and no longer floating....usually when dismantling/rebuilding the carbs you can shake the float and easily tell if it has been infiltrated--had one on my 450.

 

[BT85]

I read your post better and deleted mine, it's only leaking when fuel should be flowing, so it's not the petcock.
Floats stuck? Floats set wrong? Bad O rings? Needle valves too worn out?

I would guess a float is caught under a poorly cut gasket or something like that not letting it rise up to shut off the flow..

This is where the gas is leaking from i believe. I ran the bike for a good 2 minutes or so before it started leaking again. If i suck on the vacuum line to the petcock, fuel spills from that little hole on both carbs. I set the float height so that it should shut the needle off pretty early in hopes that it wouldnt flood like it has been. I'm not very experienced with carbs though so I'm not sure exactly what to look for.

 

[hannibal]

I've read suggestions to clean the needle valve and seat thoroughly with carb cleaner and look for any scoring on the needle valve itself. If that looks good, then it's likely that the float height needs to be adjusted. My GS750 manyal explains the (simple) process and I'm sure it's in the GS450 manual as well. If you attach a clear hose to the bowl drain, you can observe fuel height while the bike is running and adjust the floats accordingly.

 

[hannibal]

I'm still working on float height. I lowered the fuel level and put the carbs back on the bike. Started and idled fine. Came back the next evening to do a carb sync and the bike would turn over but wouldn't start.

I pulled the plugs and they were slightly wet. Looked at the fuel height thru the clear tubes hooked up to the bowl drain and I'm pretty sure it had increased from where I set it a day earlier. I'm starting to suspect a few of the needle valves are leaking fuel even though I cleaned them and they looked in good shape.

I came across this video: https://youtu.be/8wg3VJ1STSM

My current plan is to fill the carbs on my bench and leave them overnight to see if they leak and if the fuel height rises. In the video at 1:30, he uses a multi vac to test how much pressure the needle valve will hold. But if he's using a vacuum tool, does that mean he's applying suction to the valve to test it? I don't have a vacuum tool, but I'd like to try a DIY version. I just don't know if vacuum is a valid testing method or if I need to find a way to add pressure.

 

[wymple]

I have a Pontiac Fiero that I stuck a in 3800 out of a 2005 Grand Prix. It's a good 1000 lbs lighter than the GP and it's very quick. Guys tell me it must be pushing 350-400 HP to run like it does. It has 210, but I keep my mouth shut, cause I have a 350 HP 2 seater. I bet the PO thinks he really had 110 HP, maybe his previous ride was a 360 Honda. Every time the bragging gets cranked up my brain knocks about a 3rd off the numbers they spit out. You can't believe how many 160 mph 750's were made back in the late 70's.