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Extra Spark; ignition coil mod -- crazy or not??

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  • Extra Spark; ignition coil mod -- crazy or not??


    I have got an extra CDI, and an extra pair of coils for my bike, and a full wire harness as well.

    I'm wondering if it would be possible to simultaneously add these to the existing bike's ignition set up, to create a meaner, more aggressive spark. Running double coils, cdi etc, on one machine.

    I'm thinking that I can splice in the new wire harness at the existing CDI, and wire in the new one, and coils parallel to the installed set up, then split the connection at the spark plug to accept two incoming plug-wires from the two coils. These two coils will then fire simulaneously because the entire system will be linked to the single pickup coil/ignition rotor.

    Is this idea crazy or could it actually work and provide a bigger spark.? and would this actually help a bike that's running a stage 3 w 4to1 pipe and K&N pods? (Or is it just stupid?)

  • #2
    Most likely wont work.

    Wait for cyber to chime in with the technical reasons why.

    I definatly wouldn't want a ticking timebomb like that between my legs.


    • #3
      i don't buy into the larger spark thing. if your air/fuel mixure is correct & your plugs & wires & coils are in good shape the mixure will ignite.

      besides the aftermarket coils are higher voltage if you add another coil it's going to double the current but the voltage will be the same.



      • #4
        I see issues with this concept that are likely to wind up costing you a headache at minimum, and possibly both CDI's or a non-working bike.

        (A) the signal feeding into to the CDI needs to be in a particular voltage/amp range. If you split the wire to run it to two CDI's, you'd end up with half the power going to each, possibly not triggering either reliably.

        (B) If the resistance to the coils, or the plug wires is off by even a bit, then the power will hit one coil/plug-wire before the other does, and the power from one coil will feed-back into the other (may well send a jolt back up-stream, toasting the CDI). This is especially true if you're only getting signal to one CDI at a time...

        (C) Trinc is right -- there is no benefit from a bigger spark at that level if the current ignition is working properly -- once the fuel-air mix is lit properly, it's pretty much lit. More-over, if the two power-surges hit at the same time, the increase in voltage to that level may start frying the electrodes at the plug, which would turn a tiny spot of it into molten metal to splatter against the combustion chamber (cylinder walls, piston face, valve faces, etc) each time they sparked.

        (D) If improved spark is that much of an issue for you, look for replacement solid-state multiple-discharge coils to use instead. These are designed to spark several times back-to-back in very fast order, which is beneficial if for some reason the initial spark didn't take right. Realize that once a spark takes, the area around the plug gets ignited and further sparks won't hit combustable fuel-air mix normally, because the flame front is already moving away from the plug -- in limited circumstances, such as very high compression engines, the piston still moving upwards can force fresh fuel-air mix into the area of the plug for multiple discharge to work well.
        If you go this route, be careful, as noted in this webpage (someone else had posted it in a previous ignition thread):

        =-= The CyberPoet
        Remember The CyberPoet


        • #5
          Thanks guys...that's all the info I needed.

          Today I heard a comment from my friend in engineering "You're an engineer (I'm 1st yr) figure it out for yourself" -- I replied "that's what I'm doing" (by talking to you folks)...."Just go ahead and do it" he says......not quite my approach.

          Anyway, thanks alot, you've saved me some time, and potentially even some fried equipment

          mmmmmm, tasty, fried-equipment


          • #6
            You could also buy some super coils. I know Dennis Kirk carries them.
            -89 Gixxer 1100 Engine
            -Stage 3 Jet Kit / KNN Pod Filters
            -Ohlins Susupension
            -Various Other Mods