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TOPIC: "Houston, we have no ignition!"

"Houston, we have no ignition!" 4 years 6 months ago #6400

  • trikebldr
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I'm going to present a series of somewhat organized "ramblings" to try to share some info about what's really going on with our ignition systems and what to expect when we substitute aftermarket "hotter" stuff.

I'm going to first get into some electronics basics since I have no idea how much any of you understand. Sorry if a lot of it comes across as preachy, but I will be starting at ground level. Terminology will be covered first so we are all on the same page and so that everybody accurately understands what a term means.

Next I will get into the basics of what affects the spark.

Then I will go into the details of how all this coil/CDI interaction works.

I am reading a lot of blind experimentation with claimed "hotter" coils with very little known facts about the components involved. Lots of money being spent and wasted with no improvements.

If you are willing to spend some time really digesting what I will present, then keep reading my ramblings. I'm really not interested in getting bogged down in debates, at least not in the beginning. I will just be presenting some basics of electronics and basic principles of ignition.

Bill presented a case to me that gets to the heart of my reason for these ramblings, so here is the jist of the exchange. "If the resistance of the primary of a coil is decreased, wouldn't that also decrease the intensity of the spark?" This was my reply. "If the output of the CDI is steady-state, then the answer would be no. But, if the CDI can vary it's output current, then the answer would be, 'Just the opposite! It would give a hotter spark.'. But, the impedance of the primary has to be considered as well as the DC resistance to know for sure since we are dealing with a transformer here."

If you fully understood all of what was just said, then you are far along on what I will be posting. I just want to convey what determines and affects the requirements for sufficient spark.

I'll try to do one post a day.

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"Houston, we have no ignition!" 4 years 6 months ago #6401

  • Kawboy
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I'll take a front row seat. Don't want to miss anything !! (I'll even shut up and listen for a change.)

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"Houston, we have no ignition!" 4 years 6 months ago #6404

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Hopefully when you're done we can "FILE" these myths too; right along with "how to add a fuel-pump to a carb'd bike" !

I'll take the 2nd front-row seat !
1980 KZ 1300 sr# KZT30A-009997
Always High - Know Fear !

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"Houston, we have no ignition!" 4 years 6 months ago #6405

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I've dibs on the third row, I'll also be eating caramel popcorn and homemade salsa

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"Houston, we have no ignition!" 4 years 6 months ago #6407

  • KZQ
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trikebldr wrote: ...Bill presented a case to me that gets to the heart of my reason for these ramblings, so here is the jist of the exchange. "If the resistance of the primary of a coil is decreased, wouldn't that also decrease the intensity of the spark?" This was my reply. "If the output of the CDI is steady-state, then the answer would be no. But, if the CDI can vary it's output current, then the answer would be, 'Just the opposite! It would give a hotter spark.'. But, the impedance of the primary has to be considered as well as the DC resistance to know for sure since we are dealing with a transformer here."


Hi Bruce,

I guess I did not express my self fully enough in my PM. So I'll restate my issue but will be patient for the answer as I know that you will cover the issue at the appropriate time.
During my search for a set of replacement coils I spoke with an engineer from Nology who told me that their coil was not a good match for our ignition system because Kawasaki's system is not current limited and so being would over heat their coils. The exact coil I was looking at at the time escapes me but I did learn that our CDI systems (if that's what they are) are NOT current limited.

Moving on, I fitted a GM coil pack with a ballast resistor briefly until I realized that in doing so a portion of the energy was being wasted in the ballast resistor. My 81 KZ1300 wants approximately 3 ohms of primary resistance. The GM coil pack provided about .8 ohms to which I added a two ohm ballast resistor. Believing that I could provide a hotter spark if I could find a coil that already had 3 ohms of resistance, I ditched the coil pack and chose, instead, DYNA coils and have them fitted to this day.

So my question boils down to: Does the use of a ballast resistor to match the primary resistance of a coil to the capacity of the ignition system reduce the energy of the resulting spark, when compared to a coil who's primary resistance is a character of the primary winding itself?

Please don't feel it necessary to respond to this query immediately. I was just asking that you cover the concept when the time is right.

Regards

Bill
1947 Indian Chief, 1968 BSA Shooting Star, 1970 BSA 650 Lightning, 1974 Kawasaki W3, 1976 KZ900 A4, 1979 KZ750 B4, 1979 KZ750 B4 Trike, 1980 KZ550, 1981 KZ1300, 1982 KZ1100 Spectre, 1985 Kawasaki ZN1300, 1987 Yamaha Trail Way, 2000 Honda Valkyrie Tourer, 2009 Yamaha RoadLiner S

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Last edit: by KZQ.

"Houston, we have no ignition!" 4 years 6 months ago #6408

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OK, now I see better what you were asking, Bill. I won't jump straight to the reply to that because it is actually the backbone of this whole issue and will take time, and lots of words, to get to the answer. This is a very complex issue and electronics is complex in itself, but we are mixing a bit of chemistry in the pot so simple explanations are not to be found.

Question Bill; can I post links to articles I find on the internet without infringing any rights? I am finding stuff that does a better job of illustrating my points better than I have done in the past.

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