GS450 only runs with choke on

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  • Anonymous
    #1

    GS450 only runs with choke on

    I'm trying to get my '80 GS450 to run so my wife can learn how to ride on it. Last year it didn't idle well and ran poorly - like an air leak, so I;
    - had the carbs rebuilt - air mixture screw covers removed so I can adj.,
    - floats were set to where they were
    - air mixture screws were 2 1/2 on one side 3 on other
    - nothing outstanding to cause idle issue
    - replaced oring in intake manifolds- both were cracked
    - adjusted valve clearance with shims; one shim had no clearance
    - purchased new battery
    - check arc of spark plug on head, both have spark
    - checked valve timing, both right on
    - trying to adjust air mixture, but it won't run off choke or if you try to throttle it - it dies. Did notice rpm go up as I adjusted screws, so left screw turned where rpm went highest, with choke on. One side went to 3000 rpm, other side doesn't.
    I've run out of ideas and would apprecaite any help, suggestions.
    thanks
    Tags: None
    • Anonymous
      #2
      It's the carb sync.

      Michael

        Comment

        • RacingJake
          Forum Sage
          • Jun 2003
          • 2698
          • Abilene Texas
          #3
          Sounds like your main jets are cogged
          1166cc 1/8 ET 6.09@111.88
          1166cc on NOS, 1/8 ET 5.70@122.85
          1395cc 1/8 ET 6.0051@114.39
          1395cc on NOS, 1/8 ET 5.71@113.98 "With a broken wrist pin too"
          01 Sporty 1/8 ET 7.70@92.28, 1/4 ET 12.03@111.82

            Comment

            • Anonymous
              #4
              First, a quick check for intake leaks. I use either carb cleaner or ether, but some more cautious folk recommend using a spray of water. Either way, see if spraying <substance of your choice> around the intakes causes any change. If so, that's one possible cause.

              Engine compression is something reasonable? Fuel is nice & fresh? Inside of tank is clean and/or you're using an inline filter which flows fuel OK? You've checked this? Petcock screen isn't clogged?

              What I would do: Tear into the carbs. Do it yourself, and do it correctly as shown in the Carb Cleanup section. Be thorough. Rebuild using new O-rings. Also be sure to examine the diaphragms very carefully. Eyeball a carb sync before reinstalling.

              Otherwise, I don't see any flaw in your troubleshooting approach.

                Comment

                • Anonymous
                  #5
                  Air box on?

                  You know. Almost every time some one posts about a GS only running with the choke on it turns out they are testing the bike with no air box. If you'r air box is on properly, and the filter is good, clean and instlalled properly you should be abble to ballance the carbs, and get it running fine.

                    Comment

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