fj tci

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  • GARTHXS
    XS-XJ Guru
    • Nov 2007
    • 1631
    • Seattle

    #1

    fj tci

    Would a fj1100 tci work on an xs
    91 kwaka kz1000p
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  • randy
    XS-XJ Guru
    • Dec 2003
    • 4521

    #2
    Garth,

    Maybe yes, maybe no. i'm guessing that the FJ's have the advance built into the TCI just like the later XS's and XJ's. Someone here can verify that, like maybe Kat or Gareth. That being said, you'd need the boost sensor to make that work, or forget the boost sensor and use the XS mechanical advance. There is going to be a wiring issue also, I'm sure the pinout at the plugs is not the same.

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    • GARTHXS
      XS-XJ Guru
      • Nov 2007
      • 1631
      • Seattle

      #3
      maybe xj

      The reason I ask is my 78 has fjcarbs and I don't have a real way to get a vacuum to my advance so I am wondering if there is another way to make it work. So I was thinking. Maybe an xj or fj tci to eliminate the need for a vacuum advance
      91 kwaka kz1000p
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      • DGXSER
        Doctor of XSology(Deceased)
        • Nov 2008
        • 12001
        • Cincinnati, Ohio

        #4
        Hey Garth,

        Yep the XJ did incorporate the vac advance into the TCI, however the H model XSes only incorporated the Mech advance into the TCI so they still use the vac advance. AND IIRC, the XJ also used the same 3 ohm coils as the H model XSes. Which means that unless you already have, you will need to change out the coils if I am not mistaken. and dump the ballast resistor. I am not 100% certain of all that, but I think I gleened that much from some of TC's post in the past.
        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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        • randy
          XS-XJ Guru
          • Dec 2003
          • 4521

          #5
          As far as the coils go, as long as you maintain a total of 3 ohms, it won't matter which set you use. The early set of 1.5 ohm coils / 1.5 ohm resistor will work equally as well as the later 3 ohm coil / no resistor set.

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          • GARTHXS
            XS-XJ Guru
            • Nov 2007
            • 1631
            • Seattle

            #6
            advance?

            So would I have to rewire to accomodate a xj tci and would I retro fit the advance or just leave my origanal in place?
            91 kwaka kz1000p
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            • Guy_b_g
              XSive Maximus
              • May 2007
              • 790
              • Beverly Hills, Florida

              #7
              Pick up an .030 or .035 MIG welding tip and insert it into the vacuum hose to the advance (cut the hose in two) then plug the hose into one of the four vacuum nipples on the intake manifolds. That'll damp the vacuum impulses enough to let your vacuum advance work properly.
              Guy

              '78E

              Quidquid latine dictum sit, altum videtur

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              • GARTHXS
                XS-XJ Guru
                • Nov 2007
                • 1631
                • Seattle

                #8
                pulse

                I thought because the vacuum is after the butterfly the pulse is too strong and intermittant to give a good vacuum signal
                91 kwaka kz1000p
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                • Guy_b_g
                  XSive Maximus
                  • May 2007
                  • 790
                  • Beverly Hills, Florida

                  #9
                  No, it'll work fine..just has to be damped with some restriction. AlanB or someone else who has done this may also want to chime in...anyway it's a lot simpler than plumbing in a new TCI. Try it.
                  Guy

                  '78E

                  Quidquid latine dictum sit, altum videtur

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                  • cywelchjr
                    XS-XJ Super Guru(Deceased)
                    • Oct 2008
                    • 4450
                    • Sacramento, CA

                    #10
                    I thought one of the points of the fitting on the carb is that there is no vacuum at idle. I noticed when working on mine that the vacuum advance didn't see to do anything until I raised it up off idle.

                    Of course I could be wrong, but that is my recollection. I would think that the spot for the port is there on all the carbs, just plugged on the others, but then that could be wrong too.
                    Cy

                    1980 XS1100G (Brutus) w/81H Engine
                    Duplicolor Mirage Paint Job (Purple/Green)
                    Vetter Windjammer IV
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                    OEM Luggage Rack
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                    I was always taught to respect my elders, but it keeps getting harder to find one.

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                    • GARTHXS
                      XS-XJ Guru
                      • Nov 2007
                      • 1631
                      • Seattle

                      #11
                      it is

                      Originally posted by cywelchjr
                      I thought one of the points of the fitting on the carb is that there is no vacuum at idle. I noticed when working on mine that the vacuum advance didn't see to do anything until I raised it up off idle.

                      Of course I could be wrong, but that is my recollection. I would think that the spot for the port is there on all the carbs, just plugged on the others, but then that could be wrong too.
                      on the fj carbs the tower is there but I would have to drill it out then get another smaller drill and drill out the passage and finally grind a slot in the butterfly valve to give the port a gradual pull, I just dont have the tools to do that .
                      91 kwaka kz1000p
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                      • Guy_b_g
                        XSive Maximus
                        • May 2007
                        • 790
                        • Beverly Hills, Florida

                        #12
                        The vacuum advance port is a bit of a wild card.
                        there is no such port on FJ carbs so I am running off the intake boot.
                        At first when I tried this the vacuum modual would knock or click very hard at idle (at first i thought a valve was about to go)
                        Basically it was pulling WAY to much vacuum as the port on the XS carbs has a very small diameter.
                        I tried to replicate this with a small pilot jet inside the adavance line. All knocking or clicking gone and the ignition seems to advance properly.
                        Ben, I went to my local parts yard and went digging for the right cable, the FJ uses a push -pull cable (2 cables) but I went with just the pull. the cable stay on the carbs was the the crux of the job. I cut and re-welded the fj cable holder to work with my new cable. (higher than stock)
                        You MUST restrict the vacuum advance line. I used a small pilot jet inline (read this thread, i mention my tech early on), no restriction and the timing advance bangs itself very loudly.

                        ill post some pics tomorrow....
                        hope this helps.

                        The FJ carbs transformed my slug into a smooth running power machine. And with enough weight on the rear of the bike (my 110 pound wife) we get 3rd gear wheelies.
                        These posts are from this thread: http://www.xs11.com/forum/showthread.php?t=15648

                        Bfrehill did the same mod you are doing, used a manifold vacuum port. He used a small pilot jet (maybe from his old carbs?) as the restrictor.
                        Last edited by Guy_b_g; 10-26-2009, 10:31 PM.
                        Guy

                        '78E

                        Quidquid latine dictum sit, altum videtur

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                        • GARTHXS
                          XS-XJ Guru
                          • Nov 2007
                          • 1631
                          • Seattle

                          #13
                          worth a try!

                          Why not, it can't hurt
                          91 kwaka kz1000p
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