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  • #1

    Bike dies after short run

    Hello, new member here.

    A friend of mine just purchased a 1980 XS11 special as his first bike (yikes!).
    It was a non runner that he got for $500.
    While the bike sits in my garage, I've loaned him my CB550 to learn and take his test on.

    So, the gas tank is in pretty rough shape - I've removed and rebuilt the petcocks (one was leaky), and given the tank the POR15 treatment. Also pulled the carbs (they were nasty!) and replaced the bowl gaskets. Compression is within spec. and the same on all 4 cylinders.
    New plugs, gas, oil, and voila! She started right up!

    Took it down the road, and it started wanting to die at idle - by the time I got it back, it just rolled into the driveway and died. 10 minutes later, it fires back up. This time, I set a box fan in front of the bike and just let it idle for 15 minutes - no problems. Tried another test drive, same issue - about 1 mile then wants to die, and eventually does.

    Carbs are spotless (I've learned this lesson the hard way), gas is clean and tank flows fuel freely (I pulled the tank back off and opened the valves - flows like a river).

    Any ideas?
    Tags: None
  • #2
    First thing that comes to mind is the vent in the gas cap. Try riding with the cap unlocked and see what happens.
    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

    Comment

    • #3
      Hadnt even considered that - THX!

      Comment

      • #4
        When it is working on dying, check for one or two cylinders not up to the same temperature as the others. Spritzing a bit of water on each one will probably point out one or two "dead" ones, and the number oif dead ones and which ones they are will further pinpoint the problem.

        If I was placing a bet, I'd say you get two cool pipes, and they are paired 1-3 or 2-4.

        JAT...
        Ken Talbot

        Comment

        • #5
          Just a thought, the fuel valves (needle and seat assemblies) on my 78 have filter screens on the inlet side. If your subject has them as well, they may be clogged, and that would explain idling fine but starving for fuel at operating loads.
          '78 E "Stormbringer"

          Purrs like a kitten, roars like a lion, runs like a gazelle (being chased by a cheetah).

          pics http://s1209.photobucket.com/albums/...tormbringer45/

          Comment

          • #6
            I think I've discovered the problem - the fuel lines from the tank run into what appears to be a mechanical fuel pump of sorts, with a diaphragm inside ( I wondered where that part from the petcock rebuild kit went!). Took it apart, and it was all gunked up. Installed new diaphragm - will test this evening, but I'm sure this is a contributing factor.

            Comment

            • #7
              Originally posted by mmtsquid View Post
              I think I've discovered the problem - the fuel lines from the tank run into what appears to be a mechanical fuel pump of sorts, with a diaphragm inside ( I wondered where that part from the petcock rebuild kit went!). Took it apart, and it was all gunked up. Installed new diaphragm - will test this evening, but I'm sure this is a contributing factor.
              I am guessing your talking about the "Octy". It is a vacuum shut off for the fuel. And just to be sure there should be one vacuum line that runs to one of the carb intake boots. Usually the #2 carb boot but it really does not matter. Make sure it DOES NOT connect to the #2 carb BODY, the vacuum advance should be connected there.
              Nathan
              KD9ARL

              μολὼν λαβέ

              1978 XS1100E
              K&N Filter
              #45 pilot Jet, #137.5 Main Jet
              OEM Exhaust
              ATK Fork Brace
              LED Dash lights
              Ammeter, Oil Pressure, Oil Temp, and Volt Meters
              Green Monster Coils
              SS Brake Lines
              Vision 550 Auto Tensioner

              In any moment of decision the best thing you can do is the right thing, the next best thing is the wrong thing, and the worst thing you can do is nothing.

              Theodore Roosevelt

              Comment

              • #8
                I can see that it is operated by vacuum ( and the line is connected to the #2 carb boot), but what does it do?

                Comment

                • #9
                  Originally posted by mmtsquid View Post
                  I can see that it is operated by vacuum ( and the line is connected to the #2 carb boot), but what does it do?
                  It uses the engine vacuum to open up a diaphragm inside itself that allows the fuel to flow from the petcocks to the carbs. So then when the engine is operating, fuel should in theory flow to the carbs. When the engine is not running fuel will in theory not be able to flow to the carbs. The octy seems to fail frequently (thirty years will do that to it though) rebuild kits are available and some people hate the things and some people love the things. You can easily remove it and then just run the fuel lines straight to the carbs (with a filter in between, should put a filter before the octy if you keep it anyways).
                  Nathan
                  KD9ARL

                  μολὼν λαβέ

                  1978 XS1100E
                  K&N Filter
                  #45 pilot Jet, #137.5 Main Jet
                  OEM Exhaust
                  ATK Fork Brace
                  LED Dash lights
                  Ammeter, Oil Pressure, Oil Temp, and Volt Meters
                  Green Monster Coils
                  SS Brake Lines
                  Vision 550 Auto Tensioner

                  In any moment of decision the best thing you can do is the right thing, the next best thing is the wrong thing, and the worst thing you can do is nothing.

                  Theodore Roosevelt

                  Comment

                  • #10
                    Bike runs great!
                    Rode it 40 miles into work this morning, no engine problems.
                    However, the clutch is slipping - not sure if it needs adjustment, or a new clutch.

                    Comment

                    • #11
                      Originally posted by mmtsquid View Post
                      Bike runs great!
                      Rode it 40 miles into work this morning, no engine problems.
                      However, the clutch is slipping - not sure if it needs adjustment, or a new clutch.
                      Try adjusting it first before you put money into it. check the tech tip for the procedure for adjusting it.
                      Nathan
                      KD9ARL

                      μολὼν λαβέ

                      1978 XS1100E
                      K&N Filter
                      #45 pilot Jet, #137.5 Main Jet
                      OEM Exhaust
                      ATK Fork Brace
                      LED Dash lights
                      Ammeter, Oil Pressure, Oil Temp, and Volt Meters
                      Green Monster Coils
                      SS Brake Lines
                      Vision 550 Auto Tensioner

                      In any moment of decision the best thing you can do is the right thing, the next best thing is the wrong thing, and the worst thing you can do is nothing.

                      Theodore Roosevelt

                      Comment

                      • #12
                        Yup, just needed adjustment.
                        Jeez, this thing is pretty quick! I will hate to give this back to my bud.....

                        Comment

                        • #13
                          Originally posted by mmtsquid View Post
                          Yup, just needed adjustment.
                          Jeez, this thing is pretty quick! I will hate to give this back to my bud.....
                          You'll just have to get one of your own! Plenty of them for sale lately!
                          1980 XS850SG - Sold
                          1981 XS1100LH Midnight Special (Sold) - purchased 9/29/08
                          Fully Vetterized and Dynojet Kit added, Heated Grips, Truck-Lite LED headlight, Accel Coils, Irridium plugs, TKAT Fork Brace, XS850LH Final Drive & Black SS Brake lines from Chacal.
                          Here's my web page devoted to my bike! XS/XJ User's Manuals there, and the XJ1100 Service Manual and both XS1100 Service manuals (free download!).

                          Whether you think you can, or you think you cannot - You're right.
                          -H. Ford

                          Comment

                          • #14
                            Yeah, as much as I hate to I think I'll sell my cb550. She's a great bike and my first love, but it's time to move on.

                            I noticed that this bike has an aftermarket oil cooler - and during lunch, another friend tried out the XS (he has a 78 xs11) and swears that this bike must have been bored out a bit as it feels a good bit quicker than his.

                            Was there any substantial difference between 78 and 80?
                            And do people actually try to make these things faster?

                            Comment

                            • #15
                              Originally posted by mmtsquid View Post
                              Yeah, as much as I hate to I think I'll sell my cb550. She's a great bike and my first love, but it's time to move on.

                              I noticed that this bike has an aftermarket oil cooler - and during lunch, another friend tried out the XS (he has a 78 xs11) and swears that this bike must have been bored out a bit as it feels a good bit quicker than his.

                              Was there any substantial difference between 78 and 80?
                              And do people actually try to make these things faster?
                              78 was the quickest and most powerful of them all. They started getting more environmental restrictions after that and started tuning them down.
                              Nathan
                              KD9ARL

                              μολὼν λαβέ

                              1978 XS1100E
                              K&N Filter
                              #45 pilot Jet, #137.5 Main Jet
                              OEM Exhaust
                              ATK Fork Brace
                              LED Dash lights
                              Ammeter, Oil Pressure, Oil Temp, and Volt Meters
                              Green Monster Coils
                              SS Brake Lines
                              Vision 550 Auto Tensioner

                              In any moment of decision the best thing you can do is the right thing, the next best thing is the wrong thing, and the worst thing you can do is nothing.

                              Theodore Roosevelt

                              Comment

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