Not exactly, but close enough. It gives a general idea of the proportions. Specific wire sizes and number of turns would let me calculate the resistances, current and voltages at any given point in the firing cycle.
I am looking for the specific data for one of the coils, or coil-packs for the 1300s. If I knew the wire sizes and number of turns I could give actual numbers for changes in voltage, etc.
OK, I will dive into the rather complex and lengthy discussion about input versus output electrical values and how it affects spark intensity and the dangers to the output of the ignitor.
The first thing to keep in mind during all of this is that what you put in is what you get out. What that basically means is that if you are asking for more spark strength (coil output), the ignitor must be able to provide more input to the coil. Asking more from the stock ignitor is where you can get into trouble. An aftermarket CD or MSD is needed. But, that means revamping the timing pickups and mounting a not-so-small unit. Anybody who likes to tinker could make up their own pickup system.
OK, now Scotch, this part gets to the heart of your issue in that other thread. The stock system uses a ballast resistor to give a total resistance that the ignitor sees. This coil/resistor combo gives an acceptable spark for stock running. The data says that about half of the voltage is dropped across that resistor while the other half is dropped across the coil's primary. Sounds like a waste of power, huh? It is during the firing cycle, and the ignitor is designed to deal with that waste, but don't forget that the magnetic field that built up in the primary of the coil to fire the plug is now ready to collapse, also inducing a reverse current in the windings and sending it right back to the ignitor. The ignitor controlled the current and voltage when it wanted the plug to fire, but now there's nothing to control the current as that magnetic field is collapsing after the plug fires, EXCEPT that ballast resistor.
(hang on, it gets good here!) If you are running the engine at high rpm's and full throttle you are asking for the best spark available and that takes the most power from the coil. Just to jump the plug gap also requires a very high voltage, which means the magnetic field has to be built higher (stronger) before the spark will jump the gap. And, the current output of the secondary has to be high enough to give the spark enough heat to fire the air/fuel mixture well enough to burn correctly (don't forget our little candle versus the propane weed-burner analysis!). Ah, now we have a very strong magnetic field that will be collapsing on the primary once the plug has fired. The current that will be induced in the primary and sent back into the ignitor can be very high. High enough to blow the output of the ignitor if not kept to a reasonable level. This all works for the stock system because the ballast resistor is there to control that reverse current.
Now, add a coil that has a primary with the same resistance alone as the coil that needs a resistor. It is wound with the correct guage of wire and number of turns to give a "hotter" spark, but, when the magnetic field collapses after the spark there is nothing additional (besides the coils primary resistance) to resist that high reverse current. Don't forget that the ignitor controlled the voltage and current during firing of the plug, and now there is no element to control the reverse current coming back.
I know it sounds like the same resistance is available to control that reverse current, and it is, but the specs of the primary's windings have been changed to provide that total resistance, as well as a "hotter spark" (read as "more power!) and these changes also increase the amount of reverse current. Without more resistance than just the coils primary, these currents are virtually uncontrolled and more than from a stock coil.
Here's where I REALLY needed a specific coils data to do some calcs of voltage, current, etc to illustrate this. Any of you more industrious guys could do a breadboard set up to test this if you have an o'scope to see the voltages. Digital meters are not fast enough to catch and read-out those values.
This is just a very difficult subject and principle to get across here in print without a chalk board, hand jestures, a little jumping up and down, throwing a few things and actual breadboard demonstrations.
Now, I have a question. have any of you blown the ignitor soon after adding one of the so-called hotter coils that uses no resistor?
Now, remember that if you are asking for more power behind that spark, you are also asking for more power from the ignitor. There are no free lunches! Kawasaki made everything to give reasonable performance if everything was in good shape. If you like to go beyond their stated redlines, or run hard for long times, then you are pushing the limits of durability. If you are not pushing things, then I am asking you, why are you trying to improve the ignition system?
