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  • oil gas leaks

    I have my 79 special. When i run the the bike, it leaks oil out of the breather. Sometimes it doesn't do it at all. Sometimes it just pours out. More gas than oil. I have checked the oil in the crank. I pulled some out of the cranks on a stick and it won't light. So I don't think the gas is getting back into the oil at all. I ran it a little bit last summer. I haven't been able to drive it at all. I start it up try put it in gear and start to go. I just comes as a flow out of the breather. Bike runs beautiful. No miss. run perfect. no noise. Could this be a oil flow problem? or just need to rebuild the carbs?

  • #2
    "I get gas on the high carb diet."

    Yup... time to pull the carbs. Petcocks are vacuum activated. Fuel only flows to the carbs when the engine is running, and when the engine is running, is when you're flooding
    it leaks oil out of the breather.
    . Two reasons for oil to come from the airbox: One is too much oil in the crankcase, like when one checks and fills the oil with the bike on the sidestand, instead of having it on the centerstand, hence over full. The other is mistaking what you see for oil, when it is really gas dripping from the airbox, after it has mixed with the normal oily residue from the crankcase breather system, or has mixed with the oil that one sprays on the air filter element.
    Carbs need to be pulled and have new float needles installed. When the bike is running, the vacuum petcocks open and allow fuel to flow to the carbs. As the bowls fill, the floats in there rise... the floats push the needles up into the seat and shut off the flow, as needed. Yours are not doing this, but allowing the bowls to overfill and fuel runs to the airbox. Can also run into the cylinders, but as the bike is running, most gets burned, but can lead to fouled plugs.
    As for the "Light the oily stick on fire to see if gas is in the oil"... I've seen this done, and also toyed with it a little. While this is an accurate test, it doesn't always determine the presence of fuel, as it gives no indication of just what the percentage of mix is. I've done the test and have had the oil not burn, but I knew damned well there was gas in the oil. Not enough of a ratio to ignite oil... but enough to thin the oil's viscosity and honk up the bearings and other innards.
    (I have yet to take a quart of oil and pour in fuel an ounce at a time to find out at just what mixture will make this test accurate. It's on my list of things to do... same as my great "Which fuel filter traps the most sediment before it gets to the carbs" experiment. [have 6 different filters on the bench at home, just not the time to play])
    My lazy life style aside... you need to pull the carbs and replace the float needles. While you're in there, take Q tips, chrome polish, and polish up the seats where the needles live. Flush out with spray carb cleaner.
    If you have big chunks of rust and such in your float bowls, you need to pull your fuel tank, take off the petcocks and ensure that the filter screen towers are still inplace. Leaking fuel can also be caused by the towers coming off, allowing rust and crud to pass down to the carbs, where a chunk becomes lodged between the float needle and seat, holding them open. Install an in-line fuel filter just for fun, and maybe replace your fuel line, as they're twenty five years old, they crack on the inside, and rubber chunks can float to the needle/seat area, as well.
    Reset the float levels, as per "Ze book auf Instruktions" and all should be hunk-dory again.
    Before reinstalling the carbs on the bike, set them on the bench upside down, and run a fuel line to them. Purge the air from the line by flipping each float till fuel flows, then dry the needle area completely, and sit and watch for leakage. If none... go upstairs and harrass your wife fer a spell, then come down and recheck them again.
    If they're still dry, put the bowls back on them. Flip them right-side up, and do this test again. (teasing the wife at this point is optional) If no fuel is leaking out of the air jets on the "airbox side" of the carbs, then you have no worries... unless your wife is waiting for you on the stairwell with a frying pan in her hands, waiting to check your head for leakage.
    You can order new float needles cheaply from some of the places listed on this site, or hit a bike shop... they're about $5 per.
    Last edited by prometheus578; 07-28-2006, 08:39 AM.
    "Damn it Jim, I'm a doctor, not a mechanic!' ('Bones' McCoy)

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    • #3
      .. the very poetic and informative description that the sexy man Prometheus has given could be very rite and probly should happen anyway.. but since your bike is a 79, you have vent hoses that go from the carbs to the air box, so before you take your carbs off i would check to see if one of those are not pinched, kinked or blocked off some how. these hoses will be the top two on the carbs that go to the top front of the air box. if these are blocked off, this will cause your carbs to over flow when you start to move the bike.
      i phucked with a bike for two days before figuring this one out.

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      • #4
        sexy man Prometheus
        Gene, That is really scary.

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        • #5
          Prom, I'm ashamed of you

          You overlooked the insignifcant fact that the bike is a Special, and hence it has the dreaded octopus. The problem may lie there.
          I've never been able to get gasoil to burn either, but it sure did smell of gas. Speaking of lihting gas...oh wait, that's a different kind of gas.

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          • #6
            gas...oh wait, that's a different kind of gas

            If your referring to the gas generated by TEXAS CHILE, it don't need to be lighted


            mro

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            • #7
              "Venting my frustration."

              GNEPIG... Thank you once again. An oft' overlooked fact, as you stated, is plugged vent lines causing carb flooding. I, too, once clowned around for a while till I figger'ed it out. Quite rare, but still happens.
              I agree with Randy. Scarey. The last man, other than you, who said I was sexy was my old cellmate, Bronto. Hhmmm... and quite coincidentally, in line with this thread, he, too, was mummblin' something about "plugging a vent hole".
              and hence it has the dreaded octopus. The problem may lie there.
              True, John, but the needles should still stop the flow; and his bike leaks when it is running, too, when the octopus is working properly, so that would be float needles, or GNEPIG's vent hole.
              As for lighting the gas... I ""accidently"" once had a gas leak when walking up the stairs... (knowing full well that my (ex) wife was walking up behind me) Unknown to me... she had her lighter in her hand and wanted to teach me a lesson in manners . As she was reaching forward to just 'heat up me bum' a little, I unintentionally decided to have a second ""accident"". The flash of blue light in the darkened hallway was awesome!
              (Ya know... it's always the little things that you miss the most about someone)
              "Damn it Jim, I'm a doctor, not a mechanic!' ('Bones' McCoy)

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              • #8
                Pro your killing me!!!!!! I'm setting here laughing my ass off...
                DEW
                One Red "Creation 1"
                One Black"Creation 2"
                One Black"Creation 3"
                One ???? "Creation 4"
                One ???? "Creation 5"
                One ???? "Parts Bike"
                All the above 1100 Specials
                78 Standard (Ruf Ruf)
                1980 Midnight Special
                1978 650 SE

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                • #9
                  Back to the bike. Is the fuel line connected to the LOWER "T"? the carbs on the 79 have 2 "T" fittings, and upper and a lower. The upper fitting is the VENT, the lower fitting is the FUEL INLET. If the fuel line is connected to the vent, the needle and seat won't do much good.
                  Ray
                  Ray Matteis
                  KE6NHG
                  XS1100 E '78 (winter project)
                  XS1100 SF Bob Jones worked on it!

                  Comment


                  • #10
                    An oft' overlooked fact, as you stated, is plugged vent lines causing carb flooding. Quite rare, but still happens
                    Update: Not quite as rare as I stated. Friday... new Triumph Bonneville... Only a few miles into a test ride, and was stuck on the side o' the road with fuel pouring out of the airbox. Some boob at the factory pinched the carb vent line.
                    "Damn it Jim, I'm a doctor, not a mechanic!' ('Bones' McCoy)

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