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1979 gl 1000. petcock off, bike will start and continue running until it runs out of fuel, HOWEVER, turn the petcock 'on' and bike dies.
i've had this done:
carbs stripped and cleaned.
rebuilt with new slides, rings, fuel jets, intake gaskets, needles, rubber seals and filters.
petcock cleaned and rebuilt.
already a new fuel pump.

problem still happens. why???
thanks in advance!

Who rebuilt the carbs. Do they KNOW goldwing carbs. From what your saying, carbs are wrong.

ifm61 wrote: ↑Mon Jul 28, 2025 8:25 pm 1979 gl 1000. petcock off, bike will start and continue running until it runs out of fuel, HOWEVER, turn the petcock 'on' and bike dies.
i've had this done:
carbs stripped and cleaned.
rebuilt with new slides, rings, fuel jets, intake gaskets, needles, rubber seals and filters.
petcock cleaned and rebuilt.
already a new fuel pump.

problem still happens. why???
thanks in advance!

So... what you are puzzling is, why it happens? Most likely, at least one of the 4 carburetors is flooding out the engine when the fuel tank petcock is selected to the 'on' position. Correct?

That's typically the condition discovered when the air filter element is completely removed to expose the air intake plenum floor.

What brand of float valves? Also, did you use OEM jets and needles or whatever came in the rebuild kit? And what about carb and plenum seals and plenum seal itself?

robin1731 wrote: ↑Mon Jul 28, 2025 10:21 pm What brand of float valves? Also, did you use OEM jets and needles or whatever came in the rebuild kit? And what about carb and plenum seals and plenum seal itself?

MUST SPLIT THE PLENUM AND REMOVE CARBURETORS

viewtopic.php?p=815878#p815878

CYBORG wrote: ↑Mon Jul 28, 2025 8:29 pm Who rebuilt the carbs. Do they KNOW goldwing carbs. From what your saying, carbs are wrong.

that's not much help to be honest, especially when i've written 'its the carbs again' as a title...

ifm61 wrote: ↑Tue Jul 29, 2025 12:33 am

CYBORG wrote: ↑Mon Jul 28, 2025 8:29 pm Who rebuilt the carbs. Do they KNOW goldwing carbs. From what your saying, carbs are wrong.

that's not much help to be honest, especially when i've written 'its the carbs again' as a title...

Was that a successful Seafoam repair, 3 years ago?
viewtopic.php?t=77486

ifm61 wrote: ↑Tue Jul 29, 2025 12:33 am

CYBORG wrote: ↑Mon Jul 28, 2025 8:29 pm Who rebuilt the carbs. Do they KNOW goldwing carbs. From what your saying, carbs are wrong.

that's not much help to be honest, especially when i've written 'its the carbs again' as a title...

it was an attempt to get more information on the rebuild. There are a lot of steps to doing Goldwing carbs correctly. Your post pretty much says that they were not done correctly. I would suggest you send them off to someone who knows how to do them correctly, or learn how yourself. Randakk has a proper kit, and a good instruction book on how to do it correctly, if you want to learn for yourself. It takes most people, who are doing them for the first time, several on and off cycles to get them right. Short of that, a step by step of what was done may help us , help you, correct the problem

ifm61 wrote: ↑Mon Jul 28, 2025 8:25 pm 1979 gl 1000. petcock off, bike will start and continue running until it runs out of fuel, HOWEVER, turn the petcock 'on' and bike dies.
i've had this done:
carbs stripped and cleaned.
rebuilt with new slides, rings, fuel jets, intake gaskets, needles, rubber seals and filters.
petcock cleaned and rebuilt.
already a new fuel pump.

Were the carb to plenum seals and the seal between the plenum halves replaced?

gltriker wrote: ↑Mon Jul 28, 2025 10:14 pm Most likely, at least one of the 4 carburetors is flooding out the engine when the fuel tank petcock is selected to the 'on' position. Correct?

That's typically the condition discovered when the air filter element is completely removed to expose the air intake plenum floor.

This ^^^^ is probably the most important reply so far. If one of the seals I asked about above is leaking the fuel pump can force fuel past the seal and into the bottom of the plenum from where it can & will cause flooding.
For obvious reasons this will only happen when the petcock is turned On (or to Reserve) and it will stop happening when the petcock is Off.
How do I know about this? Well, lets just say that my flooding issue had nothing to do with the floats or float valves

I’m no goldwing carb expert. Mine were rebuilt when I got my Gl1100 about 10 years ago.
In those 10 years whenever it starts running a little funky, I’ll dump some seafoam in and it seems to cure the problem.
However, in my 43 year career is an automotive mechanic I’ve rebuilt lots of carburetors.
Of course, those are automotive, power equipment, and a few single cylinder motorcycle carburetors
And all those instances of a flooding engine it’s usually something to do with the float. Sunk float, stuck float, bad needle and seat.
Diagnostic wise, I have to ask did these carburetors ever work correctly and for how long?
Were they rebuilt to solve this problem or a different problem?
If you keep the RPM up will the motorcycle, continue to run?

I think the key is that it runs OK with the petcock turned off but as soon as you turn the petcock on it dies.
I'm not an expert but I've had 4 cylinder 'Wings for over 30 years and the only thing I can think of to cause that is fuel entering the plenum and causing flooding and there aren't a lot of possible causes for that.

I agree with most that a seal (either needle valve or an oring) is likely leaking somewhere, but another possible solution is that the float tangs are set wrong resulting in too rich mixture, as if something is leaking. When the petcock is OFF, the fuel starvation allows the floats to lower into a reasonable position. As soon as fuel is ON, the floats rise, enrichen the mixture causing it to die.

If you have to take the carbs apart, might as well check the float levels while you're at it.

Hmmm... You're right about that.
But I'd still start by looking inside the plenum to see if there is fuel there and if you see it put a piece of paper on the bottom so you can see where the fuel is coming from.
That will tell you whether it is coming from a carb or the plenum seal. If a carb double check the float level and whether the float valve is closing and if they are right if it is probably the seal.

I agree that’s it’s flooding the engine.
For gas to flood the plenum wouldn’t it have to come through one of the carbs?

gltriker wrote: ↑Tue Jul 29, 2025 1:06 am

ifm61 wrote: ↑Tue Jul 29, 2025 12:33 am

CYBORG wrote: ↑Mon Jul 28, 2025 8:29 pm Who rebuilt the carbs. Do they KNOW goldwing carbs. From what your saying, carbs are wrong.

that's not much help to be honest, especially when i've written 'its the carbs again' as a title...

Was that a successful Seafoam repair, 3 years ago?
viewtopic.php?t=77486

I'm glad your not a betting man Cliff. unfortunately it didn't and she's been sitting in a school workshop since where a work colleague has spent the time since 'tinkering' as in clean, rebuild etc but the problem persists... based on recent and past posts for my dilemma, i'm going to suggest he split the plenum and try replacing those seals