Carb vacuum balancing question.

Discussion in 'Airheads' started by bushyb, Dec 7, 2012.

  1. robtg

    robtg Been here awhile

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    Uni-syn is great for some carbs. However the air inlets for the main jets,
    idle jets, and vent under the diaphragm are blocked when Uni-syn is used.
    Great tool, but not for Bing CVs.
    #41
  2. _cy_

    _cy_ Long timer

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    works great with Bing carbs .. simply turn intake tube to take a reading with Uni-syn. with correct adapters ALL multi-port air flow/volume can be measured/balanced, provided adjustment are possible.

    it's normal to make adapters to use Uni-syn. but most side draft carbs will not need one, unlike Bings. let's say you need to balance dual down draft Webers on a 911 Porsche or what ever. simply make an adapter to fit to Uni-syn.

    again Uni-syn is not for everyone, but it's a quality/versatile tool to have in your toolbox.
    please excuse the dirt.. been running R80G/S pretty hard
    [​IMG]

    drag racing at Zombie Apocalypse Training Camp
    [​IMG]
    #42
  3. robtg

    robtg Been here awhile

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    I stand corrected. Your "adapter" would work fine.--RG
    #43
  4. supershaft

    supershaft because I can

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    Now we're getting somewhere. Of course they work but I could sync my carbs better with my manometer before you gets your snorkels off let alone back on.
    #44
  5. bushyb

    bushyb Adventurer

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    Thanks guys. Holy smoke, that went well and well.... What about the second part of the question?<o:p></o:p>
    #45
  6. rufusswan

    rufusswan Been here awhile

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    Personally, I think you are 'over thinking' the issue.

    On the throttle cables and the choke, the issue is are they really at closed. You don't need to worry about the fully open issue. If you can't get them fully closed, you're hosed in terms of setting idle speed. If the choke is not fully closed you will never get the idle mix correct.
    #46
  7. DoktorT

    DoktorT BigBrowedNeandereer

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    Just the standard tool of chalatans. Repeat the same thing 10 times to try overcome any other valid opinion. He is right because he says he is, and any other options therefore must be wrong. Even when he is just dead stupid wrong he's right. Just ask him. Nope, don't need to ask, just suggest any alternative, he will be happy to repeat all day long.

    His butt dyno is so finely tuned, it trumps all science. His eyes are more seeing than an electron microscope.

    Some of these airheads threads are 5 pages long, and 3 pages worth is just him repeating his demand for all and sundry to bow to his "wizdom".

    This is the ego of the Shaft, so just keep the salt handy as it takes lots of pinches to get past him and all other charlatans like him.
    #47
  8. jackd

    jackd Long timer

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    May I be so bold as to suggest that you try a 'Hamonizer' for what you're doing? (Digital balancing tool which was sold in the 'Vendors' section) Or would that be throwing more fuel on the fire? Just trying to be helpful here..... I'll go away now and watch the replies.
    #48
  9. supershaft

    supershaft because I can

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    You really should leave all the personal stuff for a when we see each other in person Dr.T. Otherwise it's just what you do.
    #49
  10. supershaft

    supershaft because I can

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    I don' t think you are over thinking the situation. You check to see if your throttle is opening up all the way by looking at it. On my own bikes I always make that adjustment. They often need it. Open the throttle lever to its stop and look at the butterfly and make sure it is open all the way and at the same time not too far open. If it isn't, adjust the stop tab for the lever.

    Make sure the choke lever goes to full on against the stop and full off against the stop. That's when they are adjusted right. IMO you really need to adjust them to the full on stop or they can be about impossible to start in cold weather.
    #50
  11. H96669

    H96669 A proud pragmatist.

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    :roflGlad I could help you with that.....somewhere else. Need more pics?....I'll be over there!:wink:
    #51
  12. _cy_

    _cy_ Long timer

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    good point ... pic's or it didn't happen :D

    SS all BS aside, I don't mind anyone drilling into what ever I post. this is why IMHO, detailed technical data on forums are among the most accurate available anywhere because it's Vetted!. anything that survives yours and others ruthless nit-picking ... odds are will be correct.

    there's detailed technical postings all over the WWW. But trouble is it's very hard to tell crap from truth. which gets back to why I've got such a high opinion on technical information posted on forums. it's vetted!!!! especially on high traffic forums like ADV with 287k members. anytime someone posts technical data. if there's any hint of a mistake. Someone will ruthlessly point it out!!! odds are usually there's several folks waiting to pounced on ANY mistakes no matter how small.

    this is why I'll go out of my way to post LOTS of clear pictures. to where there is NO doubt validity of what I've posted. not saying I've never made mistakes ... but very seldom will anything I post be fundamentally wrong.

    why do you think folks are constantly posting... Pic's or it didn't happen!!!

    (SS if need be I'll chase down as easy to use, digital camera to send you for free and/or help you get up to speed on posting pic's.)
    #52
  13. supershaft

    supershaft because I can

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    I couldn't disagree more. On so many levels. Googled BS gets a life of its own. A lot of it becomes google gospel and the BS'ers' congregate. It just keeps going and going. There's no stopping the group mentality. They need each other to both give it and take it so the loop is complete. My advise is to keep your waders pulled up high. There is some good stuff among all the crap.
    #53
  14. _cy_

    _cy_ Long timer

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    fine back it up... back up what you claim
    when I stated my believe above, reasons was stated why.
    I've personally done 500+ carbs ... don't need google to tell me what works...

    in this thread .. manometers was in question so I posted up all types of manometer from my HVAC tools to leave zero doubt that I understand how manometers work. but evidently claims backed up with evidence means little to nothing to you. you keep right on ignoring documented statements while providing none of your own.

    why don't you back it up... you post all sorts of statements with no pic's, links, etc to back it up.
    I've even offered to send a camera for free and help with learning process.

    pic's or it didn't happen...
    #54
  15. Beemerboff

    Beemerboff Long timer

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    Checked the throttle cables? you might have frayed cable which is causing one side to hang up occasionally.

    I go with the previous advice on setting- with the carbs off I set the butterflies one turn open, the mixture screws about 1/8 th turn less out than the book, and 1/16 ": free play in the throttle cables - if you can get someone else to turn the throttle you can synchronize them near enough by feel.

    If everything is in good order this will be as good as you need, and if it doesnt work you have something wrong that should be found and fixed - no point in trying to adjust it out.

    For fine tuning I use a colourtune plug , and I balance with a Synchrometer flow gauge, but that is just personal preference.

    And I check the valves by feel on a hot running engine -----.
    #55
  16. _cy_

    _cy_ Long timer

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    wow .. it's been a long time since I used a syncrometer. still got a colortune in my toolbox. a nifty tool to have around if one doesn't have a gas analyzer. when the flame goes blue, shows optimal mixture, yellow is still bit rich. a bit like tuning a natural gas stove burner by color. unless one has a bacharach fyrite gas analyzer.

    if one has not seen a colortune, there's a clear quartz window that allows viewing during combustion.
    [​IMG]
    #56
  17. chasbmw

    chasbmw Long timer

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    Three is a school that believes that colourtunes give inconsistent results on 1000cc airheads, because the mixture in the big cylinders just does not burn cleanly.

    Better to aim for adjusting the mixture screws for the most power/revs
    #57
  18. Beemerboff

    Beemerboff Long timer

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    Colourtunes work just fine on all my airheads, and the twin plug motor looks no different to the others.

    FWIW the best colour is usually just out from stumble on the way in - I can tell the difference in running between about 9 and 1200 revs, but after that any difference is too small to detect, particularly if you have worked out how the gearbox works and like to keep the motor spinning 500 revs either side of peak torque.:D
    #58
  19. supershaft

    supershaft because I can

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    That's great if you set your idle mixture JUST for idling but I don't. Idle mixtures are best set at a compromise leaning towards what gets the engine up off idle the best which is usually a bit rich just for idling. After all, our engines should not idle that much. It's bad for them on a number of different levels.
    #59
  20. supershaft

    supershaft because I can

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    To leave zero doubt that you understand manometers? None of the tools you showed are manometers. A manometer has at least two tubes. Even the Uni-syn doesn't compare pressures in real time like most would define a manometer. I try to back up my claims by making sense. Something a LOT of documentors and linkers need to focus on a lot more IMO. Maybe an explanation of how measuring one pressure at a time is still considered a manometer versus comparing pressures in real time like every manometer I have ever seen referred to as a manometer? Is that the difference between a barometer and a manometer? Links? Documentation? That's google talk. There's no need for it when you make sense. Tons of googlers use photos, links and documents to NOT make sense so I would think that would reduce your need for them? It sure does reduce my need to see any. I could care less.
    #60