Carbs pouring out like Niagara

[Guest]

Hi everybody
I have an 82 GS850G I just got and in the process of getting it road ready, I yanked the carbs and cleaned them thoroughly. I used Brasso and Qtips and removed the floats, cleaned the needles, removed the seat enclosures and cleaned them and put new o rings on them. cleaned all accessible passages (some were really plugged). Installed new gaskets. Went to other side and all diaphragms look great. Cleaned the slides well. Reinstalled them and ran gas line from an IV setup. Gas poured out of every carb like there was no tomorrow. Previous owner told me he had the same thing, gas in crankcase. When I got it, I drained 2 gallons of fuel and a little oil. Engine sounds good however.
Here's my question. I could understand 1, maybe 2, maybe even 3 floats stuck open. But not all 4??!!?? I'm wondering if there's a common denominator I'm overlooking that would cause fuel puke on all carbs at once.

Any insights from you experts? Any one else dealt with this before?
Thanks in advance.

[tom203]

Your float needle seats ain't stopping fuel from your IV setup- you need to clean carbs properly.

Also your petcock likely is no good- don't fiddle with it, just get new one : this eliminates blaming petcock .

[Steve]

Can't say why all are leaking, unless something very simple has been overlooked.

For example: how were the carbs "cleaned thoroughly"? Your brief description does not sound like a "thorough" cleaning. For that, you need to strip them down COMPLETELY and soak them overnight in Berryman's Carb Cleaner Dip (GUNK brand carb cleaner will work, too). After a thorough soaking, spraying some carb cleaner through the passages will ensure they are clean, then follow with some air to make sure. You also need to install a new set of o-rings to seal everything up. One of those o-rings is around the float valve, which is a possible source of your 'leak'.

Another possible source would be hose locations. Are you SURE you have hoses connected in the correct places?

The last possible contributor here would be petcock position. True, the floats should hold back the modest head pressure from the tank, but they are secondary. If the petcock is in the PRIme position, the floats HAVE to hold back the fuel. However, if they are less than perfect, they don't stand a chance.

.

[joe79]

I think this is Petcock.

I got my 750 at a knock down price as the PO couldn't stop the carb problem.

On RUN or RES she'd run for awhile and then starve out of fuel.

As a result he ran the bike on PRI which meant the cards overflowed through each.

Same problem as you say. A gearbox full of go go juice.

What you need to ensure is that the vacuum hose between carbs N°2 & 3 is attached to the petcock. Without this hose the Petcock will not flow fuel in any position but PRI

That to me can be the only way all four carbs can simultaneously overflow

Jo

[hampshirehog]

The guy is running an 'IV' set up so the fuel tap isn't being tested. There's a fault with the float valves somewhere - either worn needles, bad seats, missing seals or incorrectly installed floats.

[joe79]

The guy is running an 'IV' set up so the fuel tap isn't being tested. There's a fault with the float valves somewhere - either worn needles, bad seats, missing seals or incorrectly installed floats.

OK I was reading 4 not IV. Gave up trying to figure out what he meant. I'm bad

[Brendan W]

How high up is the IV bag ?

[tatu]

How high up is the IV bag ?

It doesn't matter.

[mrbill5491]

It doesn't matter.

Not sure about that, read somewhere the IV shouldn't be any higher then where the top of the tank would be on the bike and preferably, it should be as close to the same height as the petcock. It was something I came across when I was setting my carbs. Don't remember where I read it, I've slept since 2013 lol.

[posplayr]

Not sure about that, read somewhere the IV shouldn't be any higher then where the top of the tank would be on the bike and preferably, it should be as close to the same height as the petcock. It was something I came across when I was setting my carbs. Don't remember where I read it, I've slept since 2013 lol.

The top of the fuel in the IV bag should be in the range of the gas tank fuel levels (in terms of heights). The higher it is the more pressure out the bottom; think water tower.

Pressure head is measured from the difference in two heights of a column of fluid. The pressure at the needle valve is a direct function of the height of fuel above it; full tank is more pressure. I'm ignoring pressure drops due to flow rate as might be attributed to a low flow fuel filter.

[Crankthat]

Sometimes the floats will get stuck on gaskets.
Can be trimmed carefully with a sharp blade.
Would be the first place I would look with all 4 overfilling if that is the case.

Hook them up to your iv off the bike and see if all of them or just 1 leak.

Each float needle has a spring under the pin that rests against the float.
Are the springs working?

Each float has a measurement they are set at to insure the float valve sets correctly.
Did you find that measurement and make sure the tab on the float is bent to give you the correct measurement

You should have the metal tipped float valves.
If not, sometimes the rubber ones dry out and need to sit in fuel a while until they swell to work..

If you replaced them beware of non stock parts as most are known to have sealing problems.

If you have the metal valves they sometimes wear out as do the seats.
The seats have o-rings also that will leak if they start to deteriorate.

If the valve or seat have corrosion on them they will not seal.

The seats can be difficult to remove, some bend the soft brass out of shape trying to grip with pliers and such.

Welcome to the forum!


Be sure to check out basecliff website.

[tatu]

Can't say why all are leaking, unless something very simple has been overlooked.

For example: how were the carbs "cleaned thoroughly"? Your brief description does not sound like a "thorough" cleaning. For that, you need to strip them down COMPLETELY and soak them overnight in Berryman's Carb Cleaner Dip (GUNK brand carb cleaner will work, too). After a thorough soaking, spraying some carb cleaner through the passages will ensure they are clean, then follow with some air to make sure. You also need to install a new set of o-rings to seal everything up. One of those o-rings is around the float valve, which is a possible source of your 'leak'.

Another possible source would be hose locations. Are you SURE you have hoses connected in the correct places?

The last possible contributor here would be petcock position. True, the floats should hold back the modest head pressure from the tank, but they are secondary. If the petcock is in the PRIme position, the floats HAVE to hold back the fuel. However, if they are less than perfect, they don't stand a chance.

.

This is true, though it doesn't matter how high you have the tank the floats and valves are easily up to the job. There is something wrong with the set up if they leak, if there has not been fuel in the carbs for a long time it is possible that that the o rings on the fuel feed tubes between the carbs can dry out. They also will swell a bit and seal, but dealing with fuel here best make sure they're new too.