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1981 Xs1100 Carbs

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  • 1981 Xs1100 Carbs

    I JUST BOUGHT A 1981 XS1100.

    I REBUILT THE CARBS AND INSTALLED NEW JETS AND NEEDLES AND SEATS.

    ALSO GAVE THEM THE TREE CLEAN METHOD.

    NOW CARBS 1&2 OR SET AT 26MM FLOAT HEIGHT BUT THE FUEL LEVEL IS PERFECT.

    CARBS 3&4 ARE SET AT 23MM FLOAT HEIGHT AND FUEL HEIGHT IN THE BOWLS WERE PERFECT.

    THE FUEL LEVEL WAS PERFECT AND IT RAN GREAT FOR AWIHLE THEN SLOWLY SPUTTED AND DIED OUT.

    NOW THE FUEL LEVEL IN THE BOWLS ARE TOO LOW...

    IS IT NORMAL TO HAVE THE CARBS OFF MEASURMENT LIKE THIS but STILL HAVE A gret FUEL HEIGHT???

    THANKS IN ADVANCE.

  • #2
    That is exactly why I abandoned the 'fuel height' method. I pre-set all my floats and then set them up on the stand and measured the height. They were all over the place. The issue (I think) is that it needs to be done on the bike with the bike warm and idling. Make sure that both sides of each float are the same and that none of them are leaky. I also feel that if you are going to do the fuel height method, you need to be absolutely sure that your float valves are in perfect working order. If they are leaking at all, the fuel hight is going to be screwed up. My advice is just set them at 23mm and call it good. You won't be disappointed.
    '81 XS1100 SH

    Melted to the ground during The Valley Fire

    Sep. 12th 2015

    RIP

    Comment


    • #3
      OK THEN,

      So my bike needs to bet set at 23MM?

      That will help ALOT.

      I have been fighting this thing for awhile.

      Comment


      • #4
        I set mine at 23mm and have never had a problem. Runs great and plugs look good too.
        Tim Ripley - Gaithersburg, MD
        1981 XS1100 Special "Spoiled Rotten" Just sold - currently bikeless!!
        23mm float height
        120 main jets
        42.5 pilot jets
        drilled stock airbox with K&N
        Jardine 4 to 1 Exhaust
        spade fusebox
        1st and 2nd gear fix

        Comment


        • #5
          If you had them set on the bench and the fuel height was per the manual you may have another problem. Id look for kinks in the feed lines or mybe a stopped up vent hole in the gas cap. If it ran good for a while then quit you can bet tha float level didn't change all by its self! Are the plugs wet? dry? black? white? how long did it run? need more info
          wingnut
          81 SH (Daily Ride)
          81 650XJ (Brother in laws bike, Delivered)
          81 650XJ Jane Doe (Son's Ride)
          82 750XJ Project bike (Son in law's future ride)
          81 XS 400

          No man has a natural right to commit aggression on the equal rights of another; and this is all from which the laws ought to restrain him.”

          A government big enough to give you everything you want, is strong enough to take everything you have.

          Thomas Jefferson

          Comment


          • #6
            Ok, Thanks.

            I set all the carbs to 23MM.
            I will start it tommorrow and see how it runs.

            It ran for about 5 Min. I took the fuel line off and blow into it, it would take any more fuel, The floats were stopping it from allowing more fuel in. Plugs on 1&2 looked good and tan. Plugs on 3&4 were tan, But Diffently looked like it ran lean.


            Were are the Idle adjustment screws on my carbs?

            There is a little plug were everybody says that they should.
            HOW do I REMOVE these plugs?

            Comment


            • #7
              Just a thin aluminum plug.
              Drill a hole in it. Not too much pressure as the pliot screw is underneath, and you don't want to break through and then dick up the head of the pilot screw.
              Anyway... hole drilled... either thread a sheet metal screw into the hole and pop the plug out... or take a pointed thingie and pry the plug out.
              Don't muscle it out of there, either. The walls of that tower are rather thin and you could snap off a chunk.
              "Damn it Jim, I'm a doctor, not a mechanic!' ('Bones' McCoy)

              Comment


              • #8
                Ok Thanks.

                I noticed that it was pretty then around the plug so I didnt pry on them too mouch. I already drilled a hole in them.

                I will try the screw idea tommorrow. That is the only seal that I havent replaced in the carbs.

                Thanks for the HELP everyone. I will try to start it tommorrow and tell Yall how it goes.

                Comment


                • #9
                  Hey guys.

                  I started it and let it run for awhile outside.

                  She Runs GREAAAT!!! Now I just need to adjust my idle screws and syns the carbs.
                  I have a "DAMAGED SCREW REMOVER" and that is what i used to remove the little plugs above the idle srews. Worked GOOD.

                  What Spark Plugs do yall recomend for this bike?

                  PO had CHAMPION RN9YC in it.

                  NGK or CHAMPION???

                  thanks.

                  Comment


                  • #10
                    plugs

                    NGK BP6ES
                    2H7 (79) owned since '89
                    3H3 owned since '06

                    "If it ain't broke, modify it"

                    Comment


                    • #11
                      OK THANKS.

                      I WILL GO GET SOME AND SEE HOW THAT WORKS.

                      Comment


                      • #12
                        HAS ANYBODY USED A CLUTCH CABLE FROM MIKES XS?

                        I dont know if they are the same size or shape.

                        Comment


                        • #13
                          Hey ChevyBoy,

                          Here are a couple of models and parts #'s, and they are different:

                          650F: 447-26335-00-00 1235mm long
                          650SF:2M0-26335-00-00 1300mm long

                          7911F:2H7-26335-00-00 1250mm long

                          I forgot to look to see what model you have, standard or special, but the 650's are shorter because they go to the LEFT side of the bike/engine, not across to the right side like the XS11! Also, different housing, etc, so not sure if the fittings, the section that is held in place by the housing at the engine is the same distance from the end of the cable, etc!?

                          Probably best to either go to the "BAY", or BikeBandit, etc.!

                          As for the spark plugs, probably too late, but there is a LIST of available brands, models of plugs in the TECH TIPS that you can pick from!! I use the Champion and have great results, others swear by the NGK since that was OEM..... YMMV!
                          T.C.
                          T. C. Gresham
                          81SH "Godzilla" . . .1179cc super-rat.
                          79SF "The Teacher" . . .basket case!
                          History shows again and again,
                          How nature points out the folly of men!

                          Comment


                          • #14
                            I picked up a new factory clutch cable from the local Yamaha dealer.
                            xs eleven #3 -'78,'79, and now an '80

                            Comment


                            • #15
                              Hey, I have one that is nearly brand new. It is a Barnett one that is WAY better than the stock one. I no longer need it I could probably give you a killer deal.
                              '81 XS1100 SH

                              Melted to the ground during The Valley Fire

                              Sep. 12th 2015

                              RIP

                              Comment

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