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gsx600f firing only on 2&3 - changed coils NEED HELP update: PROBLEM NOW FIXED!!!

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  • gsx600f firing only on 2&3 - changed coils NEED HELP update: PROBLEM NOW FIXED!!!


    I joined today in the hope that someone can help me.

    My 1998 600 is giving grief. It only runs on 2&3 and not 1&4.

    I noted that the coils have the redundant spark system and so was fairly sure the offending item would be the coil pack dealing with 1&4.

    Having tested the coils - the offending coil had OPEN circut on the secondary windings - woohoo. The "working" coil had less than spec but still worked - which was a surprise as the spark it produced was very poor.

    I've just replaced BOTH coils to give a new leash of life to the bike along with new spark plug and caps - all nice and shiny. Couldn't wait to press the start button.

    BOOHOOOOO it's exactly the same - droning away and only 2&3 firing (downpipes hot) 1&4 stone cold.

    So next task is - is it getting the signal it needs from the pickup? I've found a red 2 way plug with yellow/green wire as the output from the pick up.

    I can't find any information relating to the timing of the pick up rotor or how to check it's working when it passes the pick up.......

    PLUS there's engine oil in the casing - is this normal? Can this be causing issues?

    Can someone please help me - I've got alot on my plate at the minute and my head isn't very clear and I've always managed to work through issues - but I'm flagging and can't seem to see clearly.

    Any help would be very much appreciated

    Last edited by cikko; 07-12-2019, 10:37 AM.

  • #2
    The timing is static. Check out the coil relay mod

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    • #3
      Thank you Steve - I'll have a look into that too


      • #4
        Yeah, i would definitely test some voltages to the coils to start with. It's also possible, and more likely that the ignitor is not sending signal before the signal gen goes out, based on prior issues like this posted. That's a swap test option if you can locate a known good one near by to test with.

        Make sure the orange wires have at least 11v going to them at the coils.

        Make sure all the connections are clean, tight, and not corroded for the entire harness. I'd check voltage before and after ever connection point to see if there are drops.

        The reason the coil mod works so well, is the coils are very sensitive to low voltage. 10v is enough to fast turn the starter, but not enough spark to fire the cylinders when cold.

        93 750 Kat

        Modified Swingarm, 5.5 GSXR Rear with 180/55 and 520 Chain, 750 to 600 Tail conversion, more to come. Long Term Project build thread

        "I've done this a thousand times before. What could possibly go wron.... Ooops!"


        • #5
          Thank you Kreylyn,

          I do have normal opertion (although poor spark on 2&3) nothing 1&4.

          Ive measured the resistance of the pick up coil and it's in spec.... I don't know anyone near me with a donor bike.

          As a temporary measure and test - I'm going to run a 12v line straight from battery to coils to exclude that as any issue at all.

          Interestingly I have looked at the iginitor circuit diagram (the basic one from the manual) and it shows the 2 outputs from the ignitor as a White wire for 1&4 and Black/Yellow for 2&3. Both of these are transistor switched. If I diode test the transistors best I can from outside the box - obviously it's potted so have no internal access.... I get 2 different values of the diode test. Now that could be other internal componentry altering the figures - but does suggest perhaps ignitor unit is faulty not giving the White 1&4 pulse for Low Tension.

          Wiring loom shows continuity from that plug at the ignitor through to the LT input to coil. I could parallel wire as a test from the connector to the coil LT to exclude marginal wiring issues.

          In fact perhaps I should do that for the other coil too as the spark is poor - combined with 12v test hard wire it should eliminate all wiring loom concerns.


          ps I will update this post as I go along for future readers' assistance.


          • #6
            What happens if you flip the coils and the wiring?

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            • #7
              The bike is fixed It was the ignitor.

              I tried extra earth to engine and extra 12v to coils as a test to give me a blue spark instead of the crappy orange piddly spark.... but to no avail.

              Having tested everything and deciding the output of the ignitor wasn't giving what it should (I had to guess as the wiring seemed ok and no test equipment to see the waveform out for coil packs A & B).

              I plugged the replacement ignitor into the loom and held my fingers crossed. It was better but wouldn't rev up past 7k rpm.

              As the bike had suffered both ingitor failure and coil A failure (so cyl 1& 4 dead) I think it was ridden by previous owner with failing coil and that has taken the ignitor out - which is why 2 components for same fault has caught me out! Plus this means cyl 1&4 was running with fuel cleaning the rings and not creating the vacuum it should for the carbs to work. So I took all plugs out and sure enough 1&4 clean 2&3 black.

              So I shot some oil into 1&4 to lube the rings and create that draw that was needed.

              Pressing the starter once rebuilt was fingers crossed again.... instant revs and lots of smoke - more than the squirt of oil I just put in. So it was cleaning itself out.

              I've taken it for a run and easily got 120mph and it pulls strong throughout the rev range.

              I'm very happy.

              Only slight hiccup is to sort out the idle speed - which after riding seems to like being 2500rpm for 10 seconds or so and settles down to about 1200rpm - I think that's float level on primary circuit of carbs iirc. I'll have to pull them off and have a tinker

              I wil be an active member if I can

              Thank you for your help guys.