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  • Fuel leaking from the air box

    4 inches of snow today, which in New Mexico means a snow day and closed schools. So i decided to sync the carbs. I hooked up the home made tool, which is four six foot fuel lines that are connected to each other and filled with two stroke oil. It started up fine, but as I fiddled with things I didn't notice that the third and fourth carb sucked oil into the intake. I shut it down and need to know what to do next. Also when this happened, I noticed fuel leaking from the air box.

    I need a little help, what happened to make the fuel leak out of the air filter box and am I ok to run the bike with that and the twostroke oil in the fuel?
    Sam Christensen
    The Chronicles of my Rebuild http://xs1100rebuild.blogspot.com

    --------------------------------------------------------
    If you are leading and no one is following, maybe your just taking a walk.

    Currently bikeless. Sold my 1980 XS1100 Special

  • #2
    one of the flots is not stoping the gas do not run it fix it

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    • #3
      it happen to me one of my flots hade a hole in it.
      the gas was running out the over foll and in to the air box.
      check the flots in all your carbs.

      Comment


      • #4
        OK, it's dumb question time!

        First, what causes floats to stick? People talk about adjusting the float height, what does that

        Second, If they moved freely before I installed the carbs, are there any tell tale signs that a float might stick?

        Third, How do you unstuck 'em? Is there a quick and dirty method if you are on a ride? And what is the correct method when you are back at the ranch?

        Fourth, Is there anyway to unstuck em without removing the carbs?
        I have just installed them for the third time after re-re cleaning them and I grow tired of pulling them past the airbox. Arggg!
        Sam Christensen
        The Chronicles of my Rebuild http://xs1100rebuild.blogspot.com

        --------------------------------------------------------
        If you are leading and no one is following, maybe your just taking a walk.

        Currently bikeless. Sold my 1980 XS1100 Special

        Comment


        • #5
          Sometimes you can free up a stuck float by tapping on the side of the carbs with a screwdriver handle or something. Just tapping hard enough to set up a vibration and jstle it loose, not whamming on it trying to shake things up. It's worth a try before you blow 15 minutes pulling the carbs.

          As for the two-stroke oil, it might foul out the plugs, but it's made to mix with gas and run through the cylinders so it shouldn't do any other damage.

          Patrick
          The glorious rays of the rising sun exist only to create shadows in which doom may hide.

          XS11F (Incubus, daily rider)
          1969 Yamaha DT1B
          Five other bikes whose names do not begin with "Y"

          Comment


          • #6
            When I tap, any idea which one I should tap? Would it be the one that is pulling the most vacuum? How will I know if it loosens up?

            Sometimes I wish life were more like a video game with cool noises that told you if you did something correctly. An undo button would be nice too.
            Sam Christensen
            The Chronicles of my Rebuild http://xs1100rebuild.blogspot.com

            --------------------------------------------------------
            If you are leading and no one is following, maybe your just taking a walk.

            Currently bikeless. Sold my 1980 XS1100 Special

            Comment


            • #7
              Originally posted by digitalsam View Post
              When I tap, any idea which one I should tap? Would it be the one that is pulling the most vacuum? How will I know if it loosens up?

              Sometimes I wish life were more like a video game with cool noises that told you if you did something correctly. An undo button would be nice too.
              Just do a few taps on each of them. Actually when you tap it will tend to jar the whole bank, but I like to tap each one in turn, starting with the outside carb on each side and working my way in.

              Mine I found that I need to rebuild my left petcock today. Went out to go to lunch and found the rubber piece from the airbox wet with gas, and gas dripping down from the petcock (not really fast, but fast enough to stay wet). Grabbed my screwdriver from the saddlebag (love having a dresser) and cinched the screws on the bottom just a tad and it seems better but I'm sure it's still seeping. Luckily I do have an extra rebuild kit around somewhere, so I guess I'll rebuild this one this weekend, that should fix it up.
              Cy

              1980 XS1100G (Brutus) w/81H Engine
              Duplicolor Mirage Paint Job (Purple/Green)
              Vetter Windjammer IV
              Vetter hard bags & Trunk
              OEM Luggage Rack
              Jardine Spaghetti 4-2 exhaust system
              Spade Fuse Box
              Turn Signal Auto Cancel Mod
              750 FD Mod
              TC Spin on Oil Filter Adapter (temp removed)
              XJ1100 Front Footpegs
              XJ1100 Shocks

              I was always taught to respect my elders, but it keeps getting harder to find one.

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              • #8
                A lot of POs disconnected the stock undo button.
                The glorious rays of the rising sun exist only to create shadows in which doom may hide.

                XS11F (Incubus, daily rider)
                1969 Yamaha DT1B
                Five other bikes whose names do not begin with "Y"

                Comment


                • #9
                  DS, the floats can also hang up on the bowl gasket. If this is the case, trim the inner sides down a little. Gunked up fuel can cause the floats to stick, which is probably not your case. The float dropping too low can cause sticking. There is a tab by the float post that can be bent to prevent this. The float level is important for the fuel mixture to be correct. With the carbs on the bench upside down, lower float level will be richer, higher float level will be leaner. It is important that they all are adjusted the same. Hang in there, you'll get it.
                  2H7 (79) owned since '89
                  3H3 owned since '06

                  "If it ain't broke, modify it"

                  ☮

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                  • #10
                    Thanks guys, I am out of day today, but will try tapping the carbs tomorrow evening. Will there be any indication that I have unstuck the float? A pop, a ding? Or do I wait and see if there is fuel leaking to tell if I succeeded?

                    Also, would a stuck float affect the vacuum of a single carb?
                    Sam Christensen
                    The Chronicles of my Rebuild http://xs1100rebuild.blogspot.com

                    --------------------------------------------------------
                    If you are leading and no one is following, maybe your just taking a walk.

                    Currently bikeless. Sold my 1980 XS1100 Special

                    Comment


                    • #11
                      Float height has no affect on vacuum. You will know the float is unstuck when fule stops leaking.

                      Patrick
                      The glorious rays of the rising sun exist only to create shadows in which doom may hide.

                      XS11F (Incubus, daily rider)
                      1969 Yamaha DT1B
                      Five other bikes whose names do not begin with "Y"

                      Comment


                      • #12
                        i learned this the hard way.

                        2 stroke oil will not hurt your engine. it will only give it a little extra lubrication.

                        a side effect will be that it will foul your spark plugs.(not 2 stroke heat range plugs) slap a new set in and you'll be good to go there.

                        leaking carbs..

                        my advice.

                        #1. install carburator rebuild kits if you haven't done it yet.
                        the factory float measurements only work on new and good parts.
                        NOT 30 year old parts, float valve springs only last for so long then they get weak.

                        #2. Install petcock rebuild kit.
                        there rubber parts only last so long and then they get brittle and hard.

                        these parts along with new feul lines will bring your fuel system back to a like new state. All measurements and adjustments recomended in your service manual will then be usable and correct.

                        Good luck
                        1979 XS1100SF Special.78 E motor/carbs, Jardine 4-2 exhaust, XS Green coils, Corbin seat, S.S. Brake lines, Hard cases, Heated grips.

                        2012 FJR1300 Gen 2. Heli bar risers, R-gaza crash bars, mccruise cruise control.

                        (2)2008 WR250R. Because kids outgrew others.

                        2007 Suzuki V-Strom 1000. (Just added 2024) pre-crashed.

                        1975 Kawasaki S1 250. My first bike. Still have it. NO I'm not selling it!!

                        Most bike problems are caused by a loose nut connecting the handlebars and the seat!!

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                        • #13
                          In a spirit level size sync gauge, there wouldn't even be enough oil to foul the plugs. Start it and enjoy the puff of smoke. Just be sure it doesn't send any wrong signals to the natives.

                          Also, if the scoot has been sitting for a while and the floats were down, its possible they just got gummed up in that position. Lots of people like to shut off the petcocks and run the bowls dry, which I reckon causes a lot of stuck floats.
                          Ich habe dich nicht gefragt.

                          Comment


                          • #14
                            Originally posted by digitalsam View Post
                            OK, it's dumb question time!
                            No such thing we are just curing ignorance. Which we all needed before we knew this stuff.

                            Originally posted by digitalsam View Post
                            First, what causes floats to stick? People talk about adjusting the float height, what does that
                            The leaking fuel can be a stuck float, or it can be dirt or debris of some kind in the float valve, between the valve and the seat. Neither of which should have been caused by your pop of oil into the vacuum. That is way downstream of the carb and will only go into the engine.

                            Originally posted by digitalsam View Post
                            Second, If they moved freely before I installed the carbs, are there any tell tale signs that a float might stick?
                            Sadly, no. I have suffered this fate with one set of carbs at least six times in a row. Even ran the bench test both upside down and right side up and all went fine. load them in and I get a leaker.

                            Originally posted by digitalsam View Post
                            Third, How do you unstuck 'em? Is there a quick and dirty method if you are on a ride? And what is the correct method when you are back at the ranch?
                            Motly outlined by the other great responses. The only I woudl add is cleaning the float valve seat and the valve and the fuel inlet T.

                            Originally posted by digitalsam View Post
                            Fourth, Is there anyway to unstuck em without removing the carbs? I have just installed them for the third time after re-re cleaning them and I grow tired of pulling them past the airbox. Arggg!
                            See above post by others....good news is by the six or seventh time it is a piece of cake to put them in and out!!!
                            Life is what happens while your planning everything else!

                            When your work speaks for itself, don't interrupt.

                            81 XS1100 Special - Humpty Dumpty
                            80 XS1100 Special - Project Resurrection


                            Previously owned
                            93 GSX600F
                            80 XS1100 Special - Ruby
                            81 XS1100 Special
                            81 CB750 C
                            80 CB750 C
                            78 XS750

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                            • #15
                              I had this happen once...

                              I repaired my octo with rtv (yeah, I know), then eventually some pieces got stuck under a float valve. Were your lines filtered?

                              I really wanted to mention that the fuel goes both ways... i.e., park downhill and it goes past the valve, down the wall, and past the rings. I though the problem was intermittent but wound up with a oil pan full of gas.
                              Last edited by area51child; 12-07-2009, 04:17 PM.
                              80 LG MNS

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