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Thread: trouble balancing ONE carb!

  1. #1
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    trouble balancing ONE carb!

    ok, well i have triple DCOE 40's on my KGC10. I've been suspicious that there was a balance problem on this one carb for a long time, the number one spark plug is usually fouled when i pull it, and the rest are usually ok. today i relocated my fuel pump so that i could finally get around to testing it, and sho-nuff that intakes are NOT balanced. so i unhooked the linkages, and started tinkering and NOTHINg will correct it.

    i need some guru's to throw out some good suggestions. I'm really stumped!!

    these are pretty old DCOE's so they aren't as adjustable as the newer versions. i will post pics to show the intake numbers.

    all the internals are matched, so they should be ok, BUT what i didn't think top do was swap the jets and stuff around from one side of the carb to the other to see if maybe i just have a bad component in there. i may run out and do that right quick..

    Pics:

    this is the setting that the other two carbs are balanced at. (just over 2)


    This is the ONLY setting that the first velocity stack will adjust to for some reason.

    can anyone PLEASE give some ideas. in the mean time i will swap the jets and stuff from one bank to the other and see if it happens on the second VS, and the first one is right. (confused yet?)

  2. #2
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    Re: trouble balancing ONE carb!

    BTW sapping the jets did NOT change the numbers at all

  3. #3
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    Re: trouble balancing ONE carb!

    Might be worth checking that there isn't air being pulled in somewhere else, either carb to gasket, gasket to manifold or even manifold to head. Are they mounted solid or on rubber mounts ?
    A bad leak can be heard through a bit of pipe, otherwise it's a matter of checking for tightness and flatness of mating surfaces.
    Good luck !

  4. #4
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    Re: trouble balancing ONE carb!

    I'm running the redline rubber o-ring gaskets, but tomorrow i plan on trying the "ether" method to see if theres a leak around the manifold, BUT it seems like if it was leaking air anywhere, then the WHOLE carb would be out of balance right?

    maybe i should take the carb apart and double check everything. wonder if theres a gasket pinched or somethings just clogged up inside?

    Thanks for the tip, i was just reading a tech guide that said an air leak was the easiest explanation for poor running conditions. i can't find anything in my tech guides about having one fouled plug though.

  5. #5
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    Re: trouble balancing ONE carb!

    If you think of each choke as a seperate entity, a leak on one side of the carb would not effect the other. The air flow is adjusted seperatley so they are independent in that respect. As you say, a pinched or damaged gasket, a cracked mating face or a loose nut would be enough to allow the engine to suck air.
    As for the plug, if it's got white/brown deposits thats running lean.
    Once again, good luck. Air leaks are a pain.

  6. #6
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    Re: trouble balancing ONE carb!

    nah, the plug is very dirty with soot. looks really rich

  7. #7
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    Re: trouble balancing ONE carb!

    How "strong" is the idle in general? Is it rock solid, or all wavery and delicate?

    Because if say you have a "global" issue like weak ignition, it could amplify a little issue with one runner. You end up trying to diagnose that runner, but in reality, fixing the ignition (assuming that is what it is) will make 95% of the problem go away.

    When I was chasing tuning issues with my Hako, I tried everything, but in the end the issue really was the cam timing was out. Once that was fixed, tuning and equalising the carbs was a snack
    Hidden Content Originally Posted by datsunfreak
    No Kev, you are eating a duck fetus.

  8. #8
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    Re: trouble balancing ONE carb!

    If your butterfly valve is even slightly bent then it will cause the butterfly to sit at idle with a progression jet exposed, causing the mixture to be constantly rich on that single circuit. Possibly also your starter circuit as gummed up adding fuel to the mixture.

  9. #9
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    Re: trouble balancing ONE carb!

    Quote Originally Posted by wookieballa
    I'm running the redline rubber o-ring gaskets, but tomorrow i plan on trying the "ether" method to see if theres a leak around the manifold, BUT it seems like if it was leaking air anywhere, then the WHOLE carb would be out of balance right?
    Air leaks at the manifold to head face aren't uncommon either. Check that all the nuts holding on the manifold are present and correct/tight?
    Hidden Content Originally Posted by datsunfreak
    No Kev, you are eating a duck fetus.

  10. #10
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    Re: trouble balancing ONE carb!

    funny you should mention the ignition, i just started my ignition upgrades.installed the pertronix points delete system, and it fired up like a champ. bought the blaster 3, but i sent it back because i would prefer the blaster 2 because it has the female connection not the male. i would rather not lose the ultra plug wires that I'm currently running.

    i will check for leaks and tightness this afternoon. i know my timing is advanced a bit because of no vacuum advance, it has some weal low end power, but once you get up to around 2K its screams when its running right.

    I'm pretty sure everything is ok, it has a nice solid idle, i have it set a little low (700ish) but i like it that way. its super quiet till you get into it a little. i think it surprises people that way LOL

    im headed to work now, when i get home i will start tinkering. I've also emailed pierce manifolds to get their take on this. i will start looking into the starting circuit of the carbs too, maybe when i installed them i failed to clean something well enough.

    Thanks for all the help so far!

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