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Hey all,
So a short time ago I removed my SOS because it was leaking constantly due to a rotted seal. My fuel line is now running straight into the carbs. I sealed off the vent hole and everything seems fine as long as I'm diligent about using the petcock when the engine is off. HOWEVER, my #2 carb seems to often overflow right after I fill up the tank. I have fully cleaned and refurbished carbs with new floats etc., so I know its not a float problem. I have a feeling it has something to do simply with the gravitational pressure of the fuel into the carbs when the tank is full. Is this anything anyone has encountered before? If so, is there a solution?
'81 CB750K, '70 C70. As long as the Honda's older than I am, I'm happy...
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Administrator
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Hmm...
No real reason for the carbs to overfill if the tank is full. Interesting that it's carb #2. Does it do it if you're on the center stand and not the side stand? (forgive me, I'm really reaching here)
Have you got the vents and gas lines routed correctly? Also, an inline fuel filter may help slow the feed/lower the pressure somewhat.
Not sure if this helps or not.
Luke M
Used to have a 1979 CB750L, sold it as a parts bike, now riding a slightly modified 1984 VT700C. Network/Field Engineer. Central OH, USA, Earth, Sol System, Milky Way Galaxy, Universe.
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Administrator
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I hate to tell you, but you have a float-needle valve problem in the #2 carb.
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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Administrator
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Well, that too. I guess I just figured that would have been looked at. That's why you're TOOLS. :-)
Luke M
Used to have a 1979 CB750L, sold it as a parts bike, now riding a slightly modified 1984 VT700C. Network/Field Engineer. Central OH, USA, Earth, Sol System, Milky Way Galaxy, Universe.
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I've completely rebuilt the carbs with new float needles and floats, so I have to assume its not them. It is really only the number two carb (where the fuel comes in) that overflows and only when my tank has just been filled. My engine also idles a bit rough and wants to die like its getting too much fuel as well. But like I said I'm only encountering it right after a fill up and it runs great once I've gone 20 or so miles into the tank.
'81 CB750K, '70 C70. As long as the Honda's older than I am, I'm happy...
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Administrator
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Dumb guy reply:
If you have a problem with a completely full tank, don't fill it so full next time.  Or here's an option: don't open the petcock all the way for the first few miles. That would restrict fuel flow a little bit as well.
Yeah yeah, I know...sue me.
Luke M
Used to have a 1979 CB750L, sold it as a parts bike, now riding a slightly modified 1984 VT700C. Network/Field Engineer. Central OH, USA, Earth, Sol System, Milky Way Galaxy, Universe.
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Administrator
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So it's not coming out the overflow on the bottom of the bowel?  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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It's only coming out of the overflow at the bottom of the bowl. I know this screams bad float, but with new floats and needles, I'm perplexed.
Nils On Sep 9, 2013, at 13:00, "TOOLS1 [via Honda CB750'S]" < [hidden email]> wrote:
So it's not coming out the overflow on the bottom of the bowel?  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
1976 CB 750-A X 2
1977 CB 750-A X 2
1977 CB 750-K X 2
1976 CB 750 F
1981 CB 750
1995 KZ 1000 P-14
1981 KZ 750 LTD
1973 CB 350
1979 CM 185 Twinstar
1982 Honda XL 80
South of Eden (Kansas City MO)
'81 CB750K, '70 C70. As long as the Honda's older than I am, I'm happy...
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Administrator
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I have replaced many needle valves, and floats only to have them leak. It might be something as simple as a piece of dirt on the needle seat. Try smacking the float bowel with a soft hammer, or screwdriver handle. This might dislodge a piece of dirt. Another thing is to polish the seat with chrome polish, and a q-tip. Finely you might need to set your float 2-3mm higher. Even though these floats might be new, they could still be 30 years old, and have dried out, and become porous.
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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Administrator
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Cracked overflow tube will do the same thing. I had one do this on the chopper and it had me scratching my head for a few days. I knew the float needles were fine...and they were!...but it was the overflow tube that was leaking. Might wanna check that out.
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Administrator
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I'd fill the tank, take the #2 float bowl off, and manually lift the float with a finger to see if it stops the fuel stream. If it stops thisway, I'd look at replacing the float, or checking the adjustment if there is one.
If you lift the float while gas is streaming , just put a few rags under it, and if the stream continues,
bad seat or float valve.
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Locked
