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CV carb "mixture" screw setting makes no difference on #2

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    CV carb "mixture" screw setting makes no difference on #2

    Having stripped, dipped and methodically gone through the CV carbs on my 82 1100GL I'm trying to "tweak in" the settings using the highest rev's method. 1, 3 and 4 all made the engine bog down when I screwed the "mixture" screw in #2 I could screw all the way until lightly seated without any perceived effect. #2 pipe get's hot just like all the others so it's obviously firing, and the bike is running great, pulls like a train.

    I replaced all o-rings, gaskets and bungs also changed the intake o-rings and the airbox boots during the winter when the carbs were stripped.

    Not sure what I'm looking for with this, can anyone suggest what might be up?

    Going back out now to put my colortune in and see what that tells me.
    It's smoke that make electronic components work.
    Every time I've let the smoke out by mistake, they never work again.
    '80 GS250T... long gone... And back!
    '86 Honda Bol D'Or... very sadly long gone
    '82 GS1000SZ
    '82 GS1100GL
    '01 Honda CBR1100XX BlackBird

    #2
    My guess is that no2 2 pilot jet is blocked. If you've got a Colourtune pop it in on no.2 and see if it's firing properly.
    79 GS1000S
    79 GS1000S (another one)
    80 GSX750
    80 GS550
    80 CB650 cafe racer
    75 PC50 - the one with OHV and pedals...
    75 TS100 - being ridden (suicidally) by my father

    Comment


      #3
      Another possibility is a broken tip on #2. When you had the screws out, did you inspect them all to make sure all the tips were there?
      If the tip of the screw is broken off and stuck in the hole, no amount of screw-turning will make a difference.

      .
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      mine: 2000 Honda GoldWing GL1500SE and 1980 GS850G'K' "Junior"
      hers: 1982 GS850GL - "Angel" and 1969 Suzuki T250 Scrambler
      #1 son: 1986 Yamaha Venture Royale 1300 and 1982 GS650GL "Rat Bagger"
      #2 son: 1980 GS1000G
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      Want a copy of my valve adjust spreadsheet for your 2-valve per cylinder engine? Send me an e-mail request (not a PM)
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      Comment


        #4
        Steve, I did inspect the screws when I took them out, I learned that when I did the VM's on my 850, one of the tips on the pilot air screws was slightly bent. They all looked good from the CV's when I put them back in after service. Of course, that doesn't discount the fact I might have been heavy handed since but I don't think so.

        I've just put my colortune in #2 to find the flame was constant at idle but yellow probably due to me leaving it set where ever, but it was there all the time so that means the jet is clear right? I turned the "mixture" screw in and the flame went blue so it does seem to be making a difference but I still couldn't tell by the engine revs.

        With it set like it is, it sounds really smooth at about 1000rpm idle, revs like there's no tomorrow and I don't get any popping or farting. Haven't tried it up the road yet or starting it from cold, that'll have to be tomorrow now since the weather's warmed up at last.

        Carb guru's, do I need to be concerned?
        It's smoke that make electronic components work.
        Every time I've let the smoke out by mistake, they never work again.
        '80 GS250T... long gone... And back!
        '86 Honda Bol D'Or... very sadly long gone
        '82 GS1000SZ
        '82 GS1100GL
        '01 Honda CBR1100XX BlackBird

        Comment


          #5
          The colourtune won't lie so you're good to go.
          79 GS1000S
          79 GS1000S (another one)
          80 GSX750
          80 GS550
          80 CB650 cafe racer
          75 PC50 - the one with OHV and pedals...
          75 TS100 - being ridden (suicidally) by my father

          Comment


            #6
            It sounds like your #2 mixture needle can't seat down far enough
            to fully shut out the fuel. It may be blocked by a piece of stubborn
            dirt. Another possibility is that there's an extra o-ring or washer
            down there. But as long as you are getting the right mixture I
            wouldn't worry.

            Comment


              #7
              I think I'm back where I started about six hours ago!

              The mechanical engineers I work with tell me my servo controllers are like black magic but in my experience carbs truely are! There were times this afternoon I doubted my own mother was who she said she was. I think the only thing that may have had a slightly more frustrating day than me is the poor old (actually new) battery on the bike. It's now dead as a door nail from all the starting and stopping.

              One thing that did bother me is when I put the colortune into #4, I couldn't get the flame to turn yellow it was a whitish blue which is typical of intake air leak I believe. I remember trying to figure out what torque to apply to the intake boots once I'd changed the o-rings because I was a little worried over the statement about shortening the life of the o-ring through over compression. I put an allen key in the two intake boot mounting bolts I could get at and both were loose. I suppose I'll have to take the carbs off again to check the rest, burnt the back of my hand just now trying to get in.

              As I said though, I think I'm back where I started. The bike runs clean as far as I can tell, pulls really well with no poping from anywhere. I think I'll leave alone until I can get the time to pull the carbs off and check the intake bolts.

              Thanks again to all for their input.
              It's smoke that make electronic components work.
              Every time I've let the smoke out by mistake, they never work again.
              '80 GS250T... long gone... And back!
              '86 Honda Bol D'Or... very sadly long gone
              '82 GS1000SZ
              '82 GS1100GL
              '01 Honda CBR1100XX BlackBird

              Comment

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