77 gs750 carb from hell

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  • tooltyme
    • Feb 2026

    #1

    77 gs750 carb from hell

    well ive tried everything and cant just get it tuned right

    ive rebuild all 4 cleaned and blew compress air, set floats to 24mm set pilot screw to 1 turn and pilot air to 1-1/4 and I get get the right two running with full choke and petcock in the on position and the other two on the left wont fire unless I plug the intake port and even still they wont stay running and any touch of the throttle it stalls, now only way I can get them running slightly is when full choke and petcock on prime and I can wave the throttle and it will rev up but no choke will die

    ive taken apart and sprayed seafoam and compressed air 30+ times still wont work im stumped
  • wymple
    Forum Sage
    Past Site Supporter
    • Apr 2014
    • 1893
    • SE Iowa

    #2
    Go to the GS Parts and Services section and open the thread on Bill(Chef1366) for carb cleaning and setup. Money well spent, when done it won't be your carbs if still sickly.

    Comment

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

      #3
      Head to this link- do the job thoroughly,or suffer!

      1981 gs650L

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

      Comment

      • chuck hahn
        Forum LongTimer
        Past Site Supporter
        • May 2009
        • 25918
        • Norman, Oklahoma

        #4
        Open the drains on them first to see if the bowls are getting fuel. If number 2..second from left as sitting on the bike..is dry then number 1 will probably also be dry.

        Take the bowls off the ones that wont fire and hold the carbs upright and work the floats..seeing that the needles drop and dont hang up. Or that the floats dont hit the gaskets.

        Next, recheck the bench syncing..may be that the slides just arent open enough. I usually look for a good 20/1000s or so as the gap at the bottom. Its something simple that wont require you to send them out. I am available most night from around 6 to 9 Oklahoma time. I will PM you my number.
        Last edited by chuck hahn; 10-23-2014, 04:51 PM.
        MY BIKES..1977 GS 750 B, 1978 GS 1000 C (X2)
        1978 GS 1000 E, 1979 GS 1000 S, 1973 Yamaha TX 750, 1977 Kawasaki KZ 650B1, 1975 Honda GL1000 Goldwing, 1983 CB 650SC Nighthawk, 1972 Honda CB 350K4, 74 Honda CB550

        NEVER SNEAK UP ON A SLEEPING DOG..NOT EVEN YOUR OWN.


        I would rather trust my bike to a "QUACK" that KNOWS how to fix it rather than a book worm that THINKS HE KNOWS how to fix it.

        Comment

        • Big T
          Forum LongTimer
          Past Site Supporter
          Super Site Supporter
          • Mar 2005
          • 12391
          • West Slope, OR

          #5
          Originally posted by tooltyme
          well ive tried everything and cant just get it tuned right


          ive taken apart and sprayed seafoam and compressed air 30+ times still wont work im stumped
          What you haven't tried is properly cleaning your carbs

          Go to Basscliffs site, download the VM tutorial and clean your carbs correctly.

          You're just ****ing in the wind until then

          Did you read thru the Top 10 Newbie Mistakes thread? I'll bet you can check off every items there
          1978 GS 1000 (since new)
          1979 GS 1000 (The Fridge, superbike replica project)
          1978 GS 1000 (parts)
          1981 GS 850 (anyone want a project?)
          1981 GPZ 550 (backroad screamer)
          1970 450 Mk IIID (THUMP!)
          2007 DRz 400S
          1999 ATK 490ES
          1994 DR 350SES

          Comment

          • chuck hahn
            Forum LongTimer
            Past Site Supporter
            • May 2009
            • 25918
            • Norman, Oklahoma

            #6
            Be sure the tiny hole in the tip of the pilot jets are open too. Very easy to over look them. And Todd, he says he completely rebuilt them..so are we to assume he did them per the tutorial or not?? Only he can answer that for us.

            I will reserve comment until that point is clarified. However, in case he did not do them per the tutorial, heres a link. And I have PMed him my number so he can call with any questions and help if needed.

            MY BIKES..1977 GS 750 B, 1978 GS 1000 C (X2)
            1978 GS 1000 E, 1979 GS 1000 S, 1973 Yamaha TX 750, 1977 Kawasaki KZ 650B1, 1975 Honda GL1000 Goldwing, 1983 CB 650SC Nighthawk, 1972 Honda CB 350K4, 74 Honda CB550

            NEVER SNEAK UP ON A SLEEPING DOG..NOT EVEN YOUR OWN.


            I would rather trust my bike to a "QUACK" that KNOWS how to fix it rather than a book worm that THINKS HE KNOWS how to fix it.

            Comment

            • chuck hahn
              Forum LongTimer
              Past Site Supporter
              • May 2009
              • 25918
              • Norman, Oklahoma

              #7
              the service manual..


              MY BIKES..1977 GS 750 B, 1978 GS 1000 C (X2)
              1978 GS 1000 E, 1979 GS 1000 S, 1973 Yamaha TX 750, 1977 Kawasaki KZ 650B1, 1975 Honda GL1000 Goldwing, 1983 CB 650SC Nighthawk, 1972 Honda CB 350K4, 74 Honda CB550

              NEVER SNEAK UP ON A SLEEPING DOG..NOT EVEN YOUR OWN.


              I would rather trust my bike to a "QUACK" that KNOWS how to fix it rather than a book worm that THINKS HE KNOWS how to fix it.

              Comment

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