Bizarro problem

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  • hillsy
    Forum Sage
    • May 2008
    • 1469
    • Brisbane, Queensland, Australia

    #16
    Originally posted by Jim R
    Nah. Remember... It runs perfectly on auxilliary tank connected to fuel line.

    Which means it's something to do with your tank / fuel tap.

    Try blocking off the vacuum and running with the tank on prime.
    Current:
    Z1300A5 Locomotive (swapped my Intruder for it), GS450 Cafe Project (might never finish it....), XT500 Commuter (I know - it's a Yamaha :eek:)

    Past:
    VL1500 Intruder (swapped for Z1300), ZX9R Streetfighter (lets face it - too fast....), 1984 GSX750EF, 1984 GSX1100EF (AKA GS1150)
    And a bunch of other crap Yamahas....

    Comment

    • Sandy
      Forum Guru
      Past Site Supporter
      • Feb 2004
      • 7503
      • Cranbrook, BC Canada

      #17
      Check fuel flow into a container from the tank. On prime it should flow about a quart in 30 seconds. Then attach a vacuum line and suck on it with the tap turned to reserve or run depending on how much fuel you have in it and the flow should be the same. Anything else will reveal a fuel tap problem. Hopefully the diaphragm is OK and you don't get a mouth full of gas, if you do you know where the problem is.
      '84 GS750EF (Oct 2015 BOM) '79 GS1000N (June 2007 BOM)

      Comment

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

        #18
        If its not running on #2 and the others ARE hot, then its getting fuel from the petcock. I think the carb float may be dragging on the bowl gasket and not letting it drop far enough to open fuel flow. That or there has been a piece of crud from the tank sucked into the float and jamming it up or clogged up the pilot jet again.
        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

        • tkent02
          Forum LongTimer
          Past Site Supporter
          • Jan 2006
          • 35571
          • Near South Park

          #19
          It still runs perfectly on the aux tank? If so the carbs must be fine, its got to be a petcock, fuel tank, or bad gas thing.
          http://img.photobucket.com/albums/v5...tatesMap-1.jpg

          Life is too short to ride an L.

          Comment

          • Spyderman

            #20
            don't forget to check the tank vent in the gas cap

            Comment

            • Jim R
              Forum Apprentice
              • May 2014
              • 56
              • Oreland, PA

              #21
              It is definitely not flowing that fast. Going to take the petcock off today. Thanks.

              Comment

              • Guest

                #22
                Easy
                Suck the vacuum line on from the petcock and when your mouth gets full of gas replace it.

                Comment

                • gustovh
                  Forum Sage
                  Past Site Supporter
                  • Oct 2006
                  • 4993
                  • Vernonia

                  #23
                  Pull the #2 plug after the engine has run with #2 not firing and see if it is wet or not, that should give you some direction. The only time something like that happened to me, I ended up clipping the end of the plug wire about 1/4 " and that cured the problem. Gremlins can be a real pain in the a$$ to find.

                  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

                  • gustovh
                    Forum Sage
                    Past Site Supporter
                    • Oct 2006
                    • 4993
                    • Vernonia

                    #24
                    Any update on this?

                    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

                    • Jim R
                      Forum Apprentice
                      • May 2014
                      • 56
                      • Oreland, PA

                      #25
                      Took the petcock apart and there "may" be a pinhole in it. Partzilla has an OEM one and only $65 so I ordered it. It will be here tomorrow.

                      Comment

                      • Jim R
                        Forum Apprentice
                        • May 2014
                        • 56
                        • Oreland, PA

                        #26
                        Update. New petcock solved the problem. Running like new. Thanks to everyone for their help.

                        Comment

                        • Guest

                          #27
                          Originally posted by Jim R
                          Update. New petcock solved the problem. Running like new. Thanks to everyone for their help.
                          Now ride that mutha!!

                          Comment

                          • loud et

                            #28
                            Originally posted by Jim R
                            Update. New petcock solved the problem. Running like new. Thanks to everyone for their help.
                            Bada boom.

                            Comment

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