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Which Katana/Bandit Coils fit GS's

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    Which Katana/Bandit Coils fit GS's

    I have a 1981 GS-650-GLX
    However, the prior owner bought parts that more or less fit and worked, and made a frankenbike out of it to get it running, so I am not sure what is "right" and what is not.

    It started running poorly, and I checked various things ...
    Eventually put a timing light on it, and found various plugs don't fire at higher RPMs (usually 1,4 sometimes 2,3)

    Voltage at the coils was a bit low (maybe 1 or 1.5 volt drop), so first thing I tried was a temporary "manual" coil relay mod (ran a wire from the coils to a quick disconnect that I already had at the middle of the handlebars)
    No difference in running.

    So I measured the coil resistances.

    Coil 2-3 was ~5 ohms and ~30kohms
    Coil 1-4 was ~5 ohms and ~90kohms

    Took the plug-connectors off and measured all the parts

    Coil 2-3: 11k each plug-connector, and 11k for just the bare coil
    Coil 1-4: 40k each plug-connector, and 11k for just the bare coil

    So 2 questions ...

    1) Are the coils good ?
    2) If I do need coils, other threads have mentioned using Katana or Bandit Coils from E-bay ... Which ones will work.

    About question one ... searching the site, I think I remember reading that the Coils themselves are supposed to be 20k with 5k (each) plugs ...
    The Coils appear to be OEM type - They are tan/beige and I believe they said Nippondenso on them, which would make me think they are NOT dyna-coils or such (and the ignitor appears to be stock too)
    I'll assume I at least need to change the plug connectors for 1-4 ... gawd knows what the P.O. was thinking there ...
    ... So ... New coils or just plug-connectors ...

    If New coils, I'll try some off E-bay; which leads to question 2:
    Which years or model of Katana or Bandit Coils would work ...
    Which will be right electrically, and which will bolt right in ...
    In searching, some for a Kat said that they were for a CDI ignition ... I would guess those are wrong ... Did some Kats come with CDI or was that something someone modded

    #2
    The problem is that your bike has 5 ohm coils if it's got a set of points. I would recommend Dyna 5 ohm coils. Anything else will be so old that you might as well buy new, and Bandit/Katana coils are 3 ohms.
    80 gs1100 16-v ported & polished, 1 mm oversize intake valves, 1150 carbs w/Dynojet stage 3, plus Bandit/gsxr upgrades

    Comment


      #3
      The 3 ohm coils will work fine on your bike. Ray.

      Comment


        #4
        I think Bandit coils are 2.2 ohms, but you could always run a ballist resistor in line.
        Ed

        To measure is to know.

        Mikuni O-ring Kits For Sale...https://www.thegsresources.com/_foru...ts#post1703182

        Top Newbie Mistakes thread...http://www.thegsresources.com/_forum...d.php?t=171846

        Carb rebuild tutorial...https://gsarchive.bwringer.com/mtsac...d_Tutorial.pdf

        KZ750E Rebuild Thread...http://www.thegsresources.com/_forum...0-Resurrection

        Comment


          #5
          According to the manual, there are not points but instead a signal generator (with advance built into it) and then the ignitor ... and then the coils.
          does this imply that the katana/bandit coils would work as is ?
          (without a ballast resistor)

          Another question
          When I was testing things, one of the things I tried was putting the spark plug leads (one at a time) on a spare plug, which I layed on top of the cylinder head (I only get dim orange sparks ... bleah)
          But anyway ... during this, I unplugged a lead (by pulling on the cap) from the idling engine ... And got nicely zapped through the cap
          In searching the archives, I read about people pulling leads with no apparent ill effects ...
          Does this imply the wires and/or caps are too leaky.
          (I can touch the wires/caps when the engine is running without getting shocked, its only when I pulled it off the plug that it got me)

          Comment

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