drippy carbs

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  • 82 GS550L Basket Case
    • Feb 2026

    #1

    drippy carbs

    We have the bike back together and running, but the carbs are dripping a small amount of gas directly onto the engine.

    The carbs were cleaned, rebuilt, and painted by Josh TheCafeKid (and they're beautiful!).
    The vent lines are installed according to BikeCliff's excellent "Where do all these hoses go?" tutorial.
    The throttle snaps shut when released.
    As far as I know, all of the covers are tight, and the drain plugs are secure.

    Sorry, no picture. But you can imagine a tablespoon of gas or so puddled on top of the engine when we got out to the bike this morning.
  • Agemax
    Forum Guru
    • Apr 2008
    • 8371
    • plymouth uk

    #2
    it could be the tee joints leaking, the tee's that join the carbs together to supply fuel, a leaky float bowl gasket or an incorrectly set float height.
    do you have pipes on the overflow tubes on the bottom of the float bowls? if so they would leak on the floor if it is a float height issue, if no pipes it would leak on the engine.
    1978 GS1085.

    Just remember, an opinion without 3.14 is just an onion!

    Comment

    • Larry D
      Forum Sage
      Past Site Supporter
      • Jul 2008
      • 4926
      • Indianapolis,IN

      #3
      Could be that the bowls and/or the drain screws aren't tightened down, the fuel line itself could be a bit loose.....or, you left the petcock on prime last night.
      Larry D
      1980 GS450S
      1981 GS450S
      2003 Heritage Softtail

      Comment

      • BassCliff

        #4
        Hi,

        Is the float height properly set?


        Thank you for your indulgence,

        BassCliff

        Comment

        • tom203
          Forum Guru
          Past Site Supporter
          • Aug 2010
          • 8925
          • Norway,Maine

          #5
          Make sure petcock is not leaking at tank mount.
          1981 gs650L

          "We are all born ignorant, but you have to work hard to stay stupid" Ben Franklin

          Comment

          • Dogma
            Forum Guru
            • Sep 2007
            • 7143
            • Mason, OH (SW)

            #6
            Lots of ways a carb can drip gas have been mentioned. I think it would be helpful to first try to find where the gas is coming from. With the bike level or on the center stand, wipe them dry and see where the first drip forms. See if you can feel the wetness on the carb to find out where that drip flowed from. Wipe them dry and start again as you track the leak. Maybe even take them out of the bike and hook them up again to ease inspection.

            I once used this method to find a cut o-ring on a T I had installed two years prior. (No it didn't leak right away. Probably the cut took a while to grow into a leaking tear.) No amount of cleaning needle seats and checking float heights would have revealed that. If I had disassembled the carbs again and looked at the o-rings, I might not have noticed the cut. I had to track the leak to the point of failure.

            Maybe some gunk did get past the screens in your carbs to hold a needle valve open. Maybe your petcock is leaking into the vacuum line. You'll just have to find out.
            Dogma
            --
            O LORD, be gracious to me; heal me, for I have sinned against you! - David

            Skeptical scrutiny is the means, in both science and religion, by which deep insights can be winnowed from deep nonsense. - Carl Sagan

            --
            '80 GS850 GLT
            '80 GS1000 GT
            '01 ZRX1200R

            How to get a "What's New" feed without the Vortex, and without permanently quitting the Vortex

            Comment

            • 82 GS550L Basket Case

              #7
              Originally posted by Agemax
              it could be the tee joints leaking, the tee's that join the carbs together to supply fuel, a leaky float bowl gasket or an incorrectly set float height.
              do you have pipes on the overflow tubes on the bottom of the float bowls? if so they would leak on the floor if it is a float height issue, if no pipes it would leak on the engine.
              No lines on the overflow tubes. We'll get those on once we figure out where the leak is. I sure hope its not the Ts. I'd really like to avoided pulling the carbs out, much less pulling them apart.

              Originally posted by Larry D
              Could be that the bowls and/or the drain screws aren't tightened down, the fuel line itself could be a bit loose.....or, you left the petcock on prime last night.
              Well, I'm pretty sure the peacock was on Full, not prime. I'm suspecting and I sufficiently tightened hose clamp on the fuel line at the petcock.

              Originally posted by BassCliff
              Hi,

              Is the float height properly set?
              Thank you for your indulgence,

              BassCliff
              Sadly, we did not verify the accuracy of the float settings or anything else when we got the rebuilt carbs back from Josh. That will be checked if we have to pull them, right before we put drain lines on.

              Originally posted by tom203
              Make sure petcock is not leaking at tank mount.
              I think this is probably it. at least I hope this is it.

              Originally posted by Dogma
              Lots of ways a carb can drip gas have been mentioned. I think it would be helpful to first try to find where the gas is coming from. With the bike level or on the center stand, wipe them dry and see where the first drip forms. See if you can feel the wetness on the carb to find out where that drip flowed from. Wipe them dry and start again as you track the leak. Maybe even take them out of the bike and hook them up again to ease inspection.

              (snip)

              Maybe some gunk did get past the screens in your carbs to hold a needle valve open. Maybe your petcock is leaking into the vacuum line. You'll just have to find out.
              yep, troubleshooting 101. now I have some great suggestions to tell Tanner where to start.

              I will update when it's solved. or not, if we can't figure it out.

              Comment

              • gustovh
                Forum Sage
                Past Site Supporter
                • Oct 2006
                • 4997
                • Vernonia

                #8
                Try dusting a little flower around the carbs/gas valve and look for wet.
                V
                Gustov
                80 GS 1100 LT, 83 1100 G "Scruffy"
                81 GS 1000 G
                79 GS 850 G
                81 GS 850 L
                83 GS 550 ES, 85 GS 550 ES
                80 GS 550 L
                86 450 Rebel, 70CL 70, Yamaha TTR125
                2002 Honda 919
                2004 Ural Gear up

                Comment

                • 82 GS550L Basket Case

                  #9
                  Sorry for the lack of updates - Tanner has been making up for "lost" time - he presented his project to the class on Wednesday and has been spending time hanging out with friend instead of working on the bike.

                  He's a bit burnt out, after the past month-long push, where it seemed like every waking minute was spent on the bike or in school.

                  We're going to try to get overflow/drain hoses on the carbs tonight or tomorrow.

                  Comment

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