carbs dumping fuel

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carbs dumping fuel

numinex
Hello all, new member. I own an 82 cb750c. I bought it all gummed up and cleaned the carbs which were pretty clean. The tank was rusted bad and the petcock was gummed up and needed a rebuild. I just got it back together and it finally runs. But it is now dumping gas out of the overflow tubes pretty bad, the idle screw is backed out pretty good. Most of the fuel dumps out of carbs 1 and 2 but 3 and 4 drip a little bit to. Any suggestions before or while I climb back into the carbs and figure out what's wrong?
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Re: carbs dumping fuel

numinex
So I am gonna replace all of the o-rings in the carbs, is there a source where I can get all the o-rings I need without buying 4 carb rebuild kits. I bought that outlaw racing one on amazon and I only uses a couple things out of it, it wasn't worth it.
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Re: carbs dumping fuel

TOOLS1
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In reply to this post by numinex
If it is coming out the overflow tubes it could be one or all of five things. First, the needle valve is bad, the rubber tips tend to get hard and not seal. Second, the needle valve seat is dirty, you can clean them with chrome polish and a Q-tip. Third, the plastic float has become pourious, and is not floating like it is supposed to. Fourth, the float height is not set correctly. Last, the brass tubes in the float bowels could be cracked, or damaged. If it was O-rings the gas would not be coming out of the overflows, it would be coming from the connections with the leaking O-rings. However if you need O-rings, you can get them at most autoparts stores.
TOOLS
Life is not about the number of breaths, you take, but the moments that take your breath away.
I don't have an anger problem. I have an idiot problem. Hank Hill
Never confuse education for intelligence.
Happiness is a belt fed weapon.
I just can't imagine what could go wrong.
No fire? No explosions? So whats the point of your story?
Those who are too smart to engage in politics are punished by being governed by those who are dumber. ~Plato
It couldn't be done, but the darn fool didn't know it, and did it anyway.
We all got problems. Ksharp
I like vintage bikes because they take me away from the clutter of technology that I work with everyday and back to a simpler time of mechanical elegance and simplicity.. "ninadm"
Darkwing Duck: The worst part of public transportation is the Public.
"That is awesome shit there" Re-Run
"Fear nothing, attack everything" Eric Berry
" Oh, you read that on the internet? Clearly it IS a massive problem. Of course it CAN’t be normal operation."

1976 CB 750-A X 2
1977 CB 750-A X 4
1977 CB 750-K
1976 CB 750 F
1981 CB 750
1966 Kawasaki SG 250
1981 KZ 750 LTD
1973 CB 350
1979 CM 185 Twinstar
1982 Honda XL 80
South of Eden (Kansas City MO)
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Re: carbs dumping fuel

numinex
In reply to this post by numinex
Concerning o-rings does it matter what material it is? And good point on the o-rings. I tested the floats and they work but I don't know how to check the height or even set the flow height. And I will be doing an even more thorough cleaning when I pull them back off. It also didn't start dumping fuel till the second time we put gas in it. The first time we got the idle right and took it around the parking lot. It got empty and died. We put a gallon back in and it wouldn't start again for another hour and it started doing this, I don't know if that is of any help though. It idles great though, I was starting to doubt this bike, now I just want to get it done sooner.
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Re: carbs dumping fuel

TOOLS1
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There is a writeup on rebuilding the CV carbs on here in the "Repair section." A search should bring it up. However what probably is going on with your carbs is that the floats have become pourious, and as it sat with gas in the carbs, they absorbed the gas, and became heavy, not floating as they should.
TOOLS
Life is not about the number of breaths, you take, but the moments that take your breath away.
I don't have an anger problem. I have an idiot problem. Hank Hill
Never confuse education for intelligence.
Happiness is a belt fed weapon.
I just can't imagine what could go wrong.
No fire? No explosions? So whats the point of your story?
Those who are too smart to engage in politics are punished by being governed by those who are dumber. ~Plato
It couldn't be done, but the darn fool didn't know it, and did it anyway.
We all got problems. Ksharp
I like vintage bikes because they take me away from the clutter of technology that I work with everyday and back to a simpler time of mechanical elegance and simplicity.. "ninadm"
Darkwing Duck: The worst part of public transportation is the Public.
"That is awesome shit there" Re-Run
"Fear nothing, attack everything" Eric Berry
" Oh, you read that on the internet? Clearly it IS a massive problem. Of course it CAN’t be normal operation."

1976 CB 750-A X 2
1977 CB 750-A X 4
1977 CB 750-K
1976 CB 750 F
1981 CB 750
1966 Kawasaki SG 250
1981 KZ 750 LTD
1973 CB 350
1979 CM 185 Twinstar
1982 Honda XL 80
South of Eden (Kansas City MO)
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Re: carbs dumping fuel

numinex
In reply to this post by numinex
Is there a way to test that besides seeing if they float in a sink. Since water is heavier than gas I could see how that could fail. And I will be checking out that thread. Hopefully I can get the carbs of cleaned and put back on quick since I have done it once already. And those screws are getting messed up on the carbs, that cheap chinalloy strips and deforms so easily. I will be replacing them this time for sure.
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Re: carbs dumping fuel

TOOLS1
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The screws messing up is not because of the material the screws are made of, it is because that are not Phillips head screws, they are JIS (Japanese Industrial Standard) and using a Phillips head screwdriver on them strips them out. I have found that the 6 in 1 screwdrivers that have the bits that can be switched around work really well on the JIS screws. The way the bits are ground, they are shaped just like the JIS tip.
TOOLS
Life is not about the number of breaths, you take, but the moments that take your breath away.
I don't have an anger problem. I have an idiot problem. Hank Hill
Never confuse education for intelligence.
Happiness is a belt fed weapon.
I just can't imagine what could go wrong.
No fire? No explosions? So whats the point of your story?
Those who are too smart to engage in politics are punished by being governed by those who are dumber. ~Plato
It couldn't be done, but the darn fool didn't know it, and did it anyway.
We all got problems. Ksharp
I like vintage bikes because they take me away from the clutter of technology that I work with everyday and back to a simpler time of mechanical elegance and simplicity.. "ninadm"
Darkwing Duck: The worst part of public transportation is the Public.
"That is awesome shit there" Re-Run
"Fear nothing, attack everything" Eric Berry
" Oh, you read that on the internet? Clearly it IS a massive problem. Of course it CAN’t be normal operation."

1976 CB 750-A X 2
1977 CB 750-A X 4
1977 CB 750-K
1976 CB 750 F
1981 CB 750
1966 Kawasaki SG 250
1981 KZ 750 LTD
1973 CB 350
1979 CM 185 Twinstar
1982 Honda XL 80
South of Eden (Kansas City MO)