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    Carb Balancing Problem

    I recently cleaned my carbs on my '82 gs750, and decided it was time to really balance them. I bought a 'Motion Pro Carb Tuner' for this task. I assembled the tuner as per the instructions (yes, I installed the restrictors). Unfortunately, I could not even balance the tuner. Every time I tried, the fluid continued to rise. I had the idle down to around 700rpm, but there was still to much vacuum for the gauge. The instructions said it couldn't handle greater than 40cmHg.

    Am I missing something here, or is my #3 cylinder really pulling that hard? If so, should it be? And if not, is this a symptom of some larger problem?

    #2
    When you say you "cleaned-up" your carbs, what exactly did you do? Did you dip them assembiled? Just spray Carb Cleaner Spray? Start removing jets and things? Please give us more details.

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      #3
      When you were balancing the motion pro, did you use the little screw adjusters on the MP? I am pretty sure you can use any carb to balance the tool; the goal is just to get the fluid levels even, right (all from memory, I could be wrong, I use a carbtune now---no balancing involved). So if it seems to be pulling the fluid to high, dial the little screws back on the MP; then get them even.

      Rick

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        #4
        I cleaned them up as described in John Bloemer's Pictorial with a little help from the service manual. I turned the screws all the way back before I even started and it wasn't enough to keep the fluid down. I figured it didn't really matter what carb I used for balancing, but every thing I had read, said to use the #3 carb because that's what the other carbs sync to. But, I'm not really sure if that matters for calibrating the tuner.

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          #5
          For calibrating, it does not matter what you use for a source. You can use your vacuum cleaner, if you can find an adapter.

          When adjusting the carbs, yes, #3 is the 'master' carb. The manual specifies that you adjust #2 to match #3, adjust #1 to be about 1/2 ball (Suzuki gauge; might be about .5 cm) above #2, then finally adjust #4 to match #1. Believe it or not, it DOES make a difference.

          .
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            #6
            post script

            Thanks for everyone's responses.

            Well it turns out that the source of my problems was the pilot/air screws. They were set too far in and that was causing too high of a vacuum in my intake boots. I set them correctly and the balancing gauge seems to work just fine. Unfortunately, I (of course) managed to shred a couple of the intake boots. Ugh, one step forward, two steps back.

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              #7
              Greetings and Salutations!!

              Hi Mr. gaveupone,

              Nice work on your carbs. Thanks for giving us the whole story, including the resolution. Sorry to hear about the boots. I think flatoutmotorcycles.com has the best prices for them. I bought mine there recently along with some other stuff. Their shipping time has improved!

              Anyway, the reason I called was to start you off with your very own magical, mystical, mind-blowing "mega-welcome". Here ya go...

              This is your official "mega-welcome". Please take notice of the "Top 10 Common Issues", the Carb Rebuild Series, and the Stator Papers. Now let me roll out the welcome mat for you...

              Please click here for your mega-welcome, chock full of tips, suggestions, links to vendors, and other information. Then feel free to visit my little BikeCliff website where I've been collecting the wisdom of this generous community. Don't forget, we like pictures! Not you, your bike!

              Thanks for joining us. Keep us informed.

              Thank you for your indulgence,

              BassCliff

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                #8
                Originally posted by gaveupone View Post
                Thanks for everyone's responses.

                Well it turns out that the source of my problems was the pilot/air screws. They were set too far in and that was causing too high of a vacuum in my intake boots. I set them correctly and the balancing gauge seems to work just fine. Unfortunately, I (of course) managed to shred a couple of the intake boots. Ugh, one step forward, two steps back.
                Can anyone verify this, it doesn't sound right to me. Setting the mixture screws to highest idle speed would lower vacuum and setting it lean increases vacuum?

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                  #9
                  Originally posted by gaveupone View Post
                  I recently cleaned my carbs on my '82 gs750, and decided it was time to really balance them. I bought a 'Motion Pro Carb Tuner' for this task. I assembled the tuner as per the instructions (yes, I installed the restrictors). Unfortunately, I could not even balance the tuner. Every time I tried, the fluid continued to rise. I had the idle down to around 700rpm, but there was still to much vacuum for the gauge. The instructions said it couldn't handle greater than 40cmHg.

                  Am I missing something here, or is my #3 cylinder really pulling that hard? If so, should it be? And if not, is this a symptom of some larger problem?
                  forget liqid bars i bought morgan carb tune from uk has stainless steel bar very accurate is use bit for gs & zrx

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