Fuel flow to all 4 carbs


Information and questions on GL1000 Goldwings (1975-1979)
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Thtfxr
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Fuel flow to all 4 carbs

Post by Thtfxr »



Good morning, New to group. Have a '76 GL1000. Have had carbs off twice to clean bowls and jets. Installed new fuel pump and seems to pump. Seems only getting fuel to the carb closest to the pump (checked the drain screws). Any idea on what I am doing wrong to get it flowing. Good spark, Etc. Thanks in advance!!


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winguyjo
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Re: Fuel flow to all 4 carbs

Post by winguyjo »

since you didn't specifically mention it ... when you were cleaning the carbs did you also remove the floats, clean the float needle bores and seats, check that the floats moved up and down freely, check float height ? also, did you remove/inspect/clean the fuel transfer tubes between the carbs ?

always bench test carbs after you have serviced them to make sure that there are no leaks and that all 4 bowls are getting fuel.
Thtfxr
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Re: Fuel flow to all 4 carbs

Post by Thtfxr »

The needle bores and seats are clean. The floats move up and down well. I need to look up the "fuel transfer tubes"....not familiar with them (sorry I'm such a rookie...singles and twins are a little more my forte). I tried to do a bench test with an external tank...If the tank is above the assembly, should that suffice? Thank you very much for the response.
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winguyjo
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Re: Fuel flow to all 4 carbs

Post by winguyjo »

yes, i try to get the fuel supply tank 3' above the carbs to get a bit of fuel pressure happening.
the carb closest to the fuel pump is #3, that one has the main fuel line going directly to it. the other 3 are fed via small aluminum transfer tubes (not sure if that is the official name , but you get the idea).
Thtfxr
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Re: Fuel flow to all 4 carbs

Post by Thtfxr »



. Are the fuel supply tubes these four rubber hoses?
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winguyjo
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Re: Fuel flow to all 4 carbs

Post by winguyjo »

going to have to wait for someone else to step in here ... most of my experience in with gl1100 ... the 1000 carb rack may be different in how the fuel gets from carb to carb, i don't recall, but those rubber hoses you point to are either vents or overflow tubes.


. this is one of 2 (?) fuel pipes on a gl1100. there are 2 different lenghts/diameters. there is also a plastic straw between the 2 plenum halves on an 1100 .; again; i don't recall many details on your 1000.
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dingdong
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Re: Fuel flow to all 4 carbs

Post by dingdong »

You don't say in your description but did you separate the plenum in your "cleaning" process. Fuel only getting to #3 carb could be something blocking the fuel passages inside the plenum. Fuel is distributed to the other 3 carbs thru these passages.
Thtfxr
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Re: Fuel flow to all 4 carbs

Post by Thtfxr »

Thanks for the reply. I will do a bench test again to see how far the fuel is going. To this point, I did not separate it.
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Maz
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Re: Fuel flow to all 4 carbs

Post by Maz »

Thtfxr wrote: Thu Nov 26, 2020 9:09 am Thanks for the reply. I will do a bench test again to see how far the fuel is going. To this point, I did not separate it.
The rubber tubes in your picture are air tubes. They enter each carb via a brass elbow which has a tiny jet inside to control the idle air flow. The fuel is fed to each carb via internal passages. These passages can really only be cleaned properly with the carbs split. If the carbs are off the bike, you'll soon see if the supply to any carb is blocked by removing the float bowls and blowing through the fuel line, or connecting a temporary fuel supply and checking for fuel through each float valve.
Maz
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Thtfxr
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Re: Fuel flow to all 4 carbs

Post by Thtfxr »

Great, thank you. I guess I was trying to keep from splitting them. I will get on that tomorrow. I certainly don’t mind the effort, I was just hesitant.
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Maz
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Re: Fuel flow to all 4 carbs

Post by Maz »

Thtfxr wrote: Thu Nov 26, 2020 1:58 pm Great, thank you. I guess I was trying to keep from splitting them. I will get on that tomorrow. I certainly don’t mind the effort, I was just hesitant.
You will, almost certainly, need a new plenum seal once you have split them.
Maz
Ironically, Common Sense is the LEAST common of all senses!
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winguyjo
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wing3 : 81gl1100i frame/82gl1100a engine/81cb900 bits. resurrection complete. naked. SOLD.
wing4 : 1977 gl1000 black w/ blue pinstripes; resurrection complete. SOLD
wing5 : 1977 gl1000 black w/gold pinstripes; nearly roadworthy when purchased, NOW RIDING.
wing6 : 1975 gl1000 blue; SOLD

Re: Fuel flow to all 4 carbs

Post by winguyjo »

right ... it's coming back to me now. i think the tube i am pointing to is for the gl1100 accelerator pump circuit, which your 1000 doesn't have.


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