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After putting everything back together, I don't even get a fire from any of the cylinders. It's as if they're not getting gas or a spark.
The bike was running pretty well. Had a bad gas leak. Figured it was a float valve issue. Pulled the carbs. Cleaned out all the gook with carb cleaner. Only replaced the needle valves and bowl gaskets. The floats sat more into the bowl with the old needle valves (lower when turned upside down to work on them), which led me to believe that the springs in the old needle valves had weakened.
I didn't change any settings. Wondering if I should put the old needle valves back in.
Any suggestions?
"To strive, to seek, to find, and not to yield."
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Are the plugs wet with gas?
1981 CB750K with 900 cams
90K KM's, rebuilt head, rebuilt carbs, upgraded valve stem seals
My wife's recipe website that I'm trying to help promote: Strawberries for supper. Yes, I am a lucky man.
My cb750 video site
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Crack open the over flow screws on the bottom of the carb to make sure you are getting fuel to all of them.
Simple if some one else can, why can't I
Jamie
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Good idea. Also, I discovered I may have hooked the choke cable back up wrong. As I was going to take the carbs back out and put the old needle valves back in, I manually held the choke closed. I only had a little charge left, but I got a putt out of it before it completely lost charge.
I need to figure out how to really hook the choke cable back up and try again when I have more charge.
Thanks.
"To strive, to seek, to find, and not to yield."
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Administrator
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If the battery is really weak they will not run. Also did you pull the pilot jets out to clean them?
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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I didn't take any jets out, just cleaned all the holes.I'll try it with a revived battery or a jump, and fix the choke.
"To strive, to seek, to find, and not to yield."
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Administrator
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Those jets are impossible to clean without removing them. I have a thread in the repair section that shows how to remove them.
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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I've gotten needles before that were different lengths than the ones they were supposed to be direct replacements for. Ran into a similar issue like this and that was the problem-longer needles were causing my previous float level setting to cut fuel flow off completely.
I doubt it's your pilot jets since they wont really prevent the bike from starting,and it was running well before.
Like Shultz said,remove a drain plug,or pop a bowl off, to verify your getting fuel. That'd be the 1st step. After that,check for spark at the plugs. Actually,checking for spark would be easier and faster to check first.Im lazy like that ;)
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Thanks. Good confirmation. Since I got a pop before it totally lost its charge, I'm suspecting one of the problems is malfunctioning choke cable.
If I remove a drain plug and there is gas getting into the bowl, even if it starts after fixing the choke, what could be any ongoing problem for having slightly too high of needle valves? I'm wondering if I still should go in and put the old needles back in.
"To strive, to seek, to find, and not to yield."
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Has nothing to do with the spring in the needle valves.
You put in new needles and seats anyway. But did you
check the float levels as described in the workshop manual?
The float levels are 98% of the function of the carb
other than making sure the idle jets are not clogged up.
You do need to get help from a more experienced MOTORCYCLE mechanic if possible.
On a Roadstar Adventure.
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Thanks all. Re-set the float valves according to specs. Back to running great. Thank you for all the guidance.
"To strive, to seek, to find, and not to yield."
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Administrator
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Yay!  Another happy ending!
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Hey guys, I'm having a similar problem with my 81 cb900c. It was having troubles starting it up, and it was running pretty rough. I took the carbs out yesterday and cleaned them out good, but it clearly didn't need to be done, cause it already looked really clean inside all four... I changed the float valve anyways since I was in there. When I started it up it just kept turning, and no luck. Today I took them back out, and put the old float valves in. I tried starting it up again, but noticed now it's pouring out fuel from two of the drains pretty badly! Maybe the floats are stuck now? Not too sure. But I know I can't afford to get it towed to a shop and fixed right now, so hopefully you guys can offer some insight.
Thanks in advance.
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Administrator
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Your needles and seats are not sealing, allowing the carbs to overflow. Try cleaning the seats with a Q-tip and chrome polish. You might also need to adjust the float height. As for it not wanting to start, it could be carb/fuel related, ignition, or even mechanical problems preventing the engine from starting. Have you checked for spark? Also even though the carbs look clean, the pilot jets could still be plugged, you might want to recheck them.
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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This post was updated on .
Haha actually...when I took the carbs off the last time, I forgot to close the drain valve  So yeah, after that it started up again lol.
Pretty sure they definitely gave me the wrong carb kit though.
After putting everything back the way it was, it still runs pretty rough, way worse actually.
It also has a continuous backfire happening out of my left muffler, but it was like that before.
Any ideas on that?
I'm guessing valve shims need to be adjusted. Gunna take the valve cover off again tomorrow and measure the gap.
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Administrator
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Vacuum leak, or aircut valve in one of the carbs is bad.
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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Locked
