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  • #1

    Strange gas leak

    Gentlemen, I synched my carbs on a remote tank and all went well. When I hooked up my regular tank, gas poured out of #1 with the tank on prime. Thinking stuck float, I shook up the carbs, but still leaked gas. I took the bowl off of the bottom and the float seemed to move okay. I then held the float to close the valve and turned to prime; no gas came past the float needle, but poured into the airbox.

    Where can it be coming from if the needle seals? I thought the fuel inlet/needle was a closed curcuit. I'm about ready to solve my carb problem with a match.
    "Time is the greatest teacher; unfortunately, it kills all of its students."
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  • #2
    LoHo,
    Hate to say it, but pull the carbs off the bike and use a "C" clamp to mount them to a 2X6. Then, turn them upside down, remove all 4 float bowls, and then put the aux fuel tank to them. Look around the outside of the needle, as the new carbs use an "O" ring that may be pinched or cracked. You should NOT see any fuel out of the carbs, so long as the aux tank is less than 3' above the carbs..
    Ray Matteis
    KE6NHG
    XS1100 E '78 (winter project)
    XS1100 SF Bob Jones worked on it!

    Comment

    • #3
      Just curious: did you recently rebuild your petcocks?
      1979 XS1100F
      2H9 Mod, Truck-Lite LED Headlight, TECHNA-FIT S/S Brake Lines, Rear Air Shocks, TKAT Fork Brace, Dyna DC-I Coils, TC Fuse Block, Barnett HD Clutch Springs, Superbike Handlebars, V-Star 650 ACCT, NGK Irridium Plugs, OEM Exhaust. CNC-Cut 2nd Gear Dogs; Ported/Milled Head; Modded Airbox: 8x8 Wix Panel Filter; #137.5 Main Jet, Viper Yellow Paint, Michelin Pilot Activ F/R, Interstate AGM Battery, 14MM MC, Maier Fairing, Cree LED Fog Lights.

      Comment

      • #4
        Nope, I rebuilt the petcocks four years ago and they have not been an issue.

        Ray, what I'm saying is that the needle seals the fuel inlet, but gas leaks through the intake side of the carb. I didn't think that was possible.
        "Time is the greatest teacher; unfortunately, it kills all of its students."

        Comment

        • #5
          IF the needle and seat stop the fuel, and it comes out of the intake bell, there is a break in the carb body. What I was trying to say about the '80 up carbs is that they do not have a seat that bolts in with a gasket, they have a seat that is held in with a clamp, and uses an O ring to seal. That O ring could be bad, cheaper than a replacement carb body...
          Ray Matteis
          KE6NHG
          XS1100 E '78 (winter project)
          XS1100 SF Bob Jones worked on it!

          Comment

          • #6
            Nevermind...cracked fuel line that squirted gas on top of the carb and airbox.
            "Time is the greatest teacher; unfortunately, it kills all of its students."

            Comment

            • #7
              Good news, easy fix!!
              Ray Matteis
              KE6NHG
              XS1100 E '78 (winter project)
              XS1100 SF Bob Jones worked on it!

              Comment

              • #8
                Originally posted by LoHo View Post
                Nevermind...cracked fuel line that squirted gas on top of the carb and airbox.
                lo......murphy sure seems to enjoy throwin' you curves Larry..........should stick to cookin' for the XS11 herd. That had definite good results......each time.
                81H Venturer1100 "The Bentley" (on steroids) 97 Yamaha YZ250(age reducer) 92 Honda ST1100 "Twisty"(touring rocket) Age is relative to the number of seconds counted 'airing' out an 85ft. table-top.

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                • #9
                  My cooking and my wrenching do have something in common: in about twenty-four hours, both turn to s**t....
                  "Time is the greatest teacher; unfortunately, it kills all of its students."

                  Comment

                  • #10
                    Food and drink warning

                    LoHo, that last comment has me cleaning my keyboard.

                    Glad you had an easy fix!
                    79 SF & 80 LG MNS
                    73 & 74 RD 350's
                    73 Honda CL 450
                    Graveyard - '81 XS850 Special

                    All of my bikes are projects, maybe one day I'll have them running.

                    Comment

                    • #11
                      Continuing to jack up my XS, I reset the floats at 24mm, as 23mm seemed too rich. Synching the carbs seemed weird; some adjustments led to zero vacuum on three, then more screw turning would lead to zero vacuum in four. Then it would gradually rev up, and wishfully thinking I'd broken through some clog, I'd drop the idle screw a bit, then a bit more, then more, until it no longer made contact. (Much cursing and blasphemy).

                      I did a search of revving, which I knew had to be a vacuum leak. But the vac hoses are good, the vac plugs new and pliant. My search suggested spraying the boots with something to see if the engine revs up. I knew that before, but was focused on carb adjustment and had dismissed a leak, as I was set on finding the problem in the 3 and 4 carbs and adjustments. Spaying 1 and 2 with starting fluid had no effect. I sprayed #4, and she revved even higher. I did it again and she revved more. Okay, progress. Then I sprayed #3, and it revved even more...WTF? I took it all apart again and found

                      Notice the missing chunks of gasket. The bike had tried to tell me about this before by doing little backfire coughs, but I convinced myself it was going through the carbs.

                      I took all four boots off, cleaned off the old gaskets, an RTVed them back into place. I put her back together, and like magic, my adjustments actually had an effect on vacuum levels. I did a real synch (I had lost confidence in my ability to do one after several failed attempts with an unknown double vacuum leak). Took her for a ride and she is smoother than ever.

                      Okay, I've gotta go. I've scheduled another ACCT misadventure with two or three bent valves for early June, so I'll catch you later.
                      Last edited by LoHo; 04-11-2015, 08:01 PM.
                      "Time is the greatest teacher; unfortunately, it kills all of its students."

                      Comment

                      • #12
                        Lol. We've both been down the bent valve road before. All we have to remember now is hand-turn many times to mske sure dots stay aligned, snd never-ever turn that wrench if you feel resistance.
                        1979 XS1100F
                        2H9 Mod, Truck-Lite LED Headlight, TECHNA-FIT S/S Brake Lines, Rear Air Shocks, TKAT Fork Brace, Dyna DC-I Coils, TC Fuse Block, Barnett HD Clutch Springs, Superbike Handlebars, V-Star 650 ACCT, NGK Irridium Plugs, OEM Exhaust. CNC-Cut 2nd Gear Dogs; Ported/Milled Head; Modded Airbox: 8x8 Wix Panel Filter; #137.5 Main Jet, Viper Yellow Paint, Michelin Pilot Activ F/R, Interstate AGM Battery, 14MM MC, Maier Fairing, Cree LED Fog Lights.

                        Comment

                        • #13
                          Ian, I've managed to bend valves on two occasions after I installed a mislabeled ACCT, both times when starting her up after work. I now have a correct ACCT and think I'm done with that particular issue, but we'll see....
                          "Time is the greatest teacher; unfortunately, it kills all of its students."

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