TOPIC:

I am looking at buying a set of Dyna Coils for my KZ900, Is it the gray 2.2 ohm ones that I need or is it the green 3 ohm coils?

Maybe neither.

2.2 Ohm - no - unless you are going to run a Dyna 2000 ignition system, the 2.2 Ohm coils are too low resistance.

3.0 Ohm - only if you are running a Dyna-S or similar electronic ignition, or you plan on converting from points in the very near future. Although the 3.0 Ohm coils will work with points, the points will pit much quicker than usual.

5.0 Ohm - yes if you are running points and plan on staying with points in the near term. The 5.0 Ohm coils will work with points, and with the Dyna-S ignitions if you choose to replace the points in the future.

This bike has a later model KZ electronic ignition system.

It varies a fair amount as to what coils you'll need - do you have the specifics of what year/model the ignitor is from?

Some bike would use 2.2 ohm coils, others 3 ohm - and the 79/80 year 1000's used 1.5 ohm, but with a ballast resistor in the circuit.

The ignition was put on by the previous owner so I'm not sure. I will try to look through the forum and maybe can find how to test this?

A volt-ohm-meter is all you need for the test. Set it to Rx1 scale and measure the primary leads going into the coils (after disconnecting them from the wiring harness). Measure each coil individually and you'll be able to read their values directly from the meter.

They both measured about 2.6 ohms. So I guess the green 3 ohms are the right ones. Thanks guys

N0NB wrote:

A volt-ohm-meter is all you need for the test. Set it to Rx1 scale and measure the primary leads going into the coils (after disconnecting them from the wiring harness). Measure each coil individually and you'll be able to read their values directly from the meter.

That's a quite dangerous way of measuring the resistance of the coils.
Some bikes use a ballast resistor. You can skip the ballast resistor if the overall resistance of the new coils is the same as the old ones including the ballast resistor.
Ballast resistors can fail, the result being a fried CDI...

Post edited by: Paling1, at: 2007/04/17 05:13

Paling1 wrote:

N0NB wrote:

A volt-ohm-meter is all you need for the test. Set it to Rx1 scale and measure the primary leads going into the coils (after disconnecting them from the wiring harness). Measure each coil individually and you'll be able to read their values directly from the meter.

That's a quite dangerous way of measuring the resistance of the coils.
Some bikes use a ballast resistor. You can skip the ballast resistor if the overall resistance of the new coils is the same as the old ones including the ballast resistor.
Ballast resistors can fail, the result being a fried CDI...<br><br>Post edited by: Paling1, at: 2007/04/17 05:13

But as far as I know the only KZ's with a ballast resister are certain years of KZ1000's, and he has a KZ900.

And I know that none of the KZ four stroke models had CDI ignition, although the two stroke triples did.

Ballast resisters fail by increasing resistance, not by decreasing it (it's the nature of their construction), so if a ballast resister fails you are going to get little or no current.

Jeff, I know you are the guru of KZ trivia but my shaftie service manual (KZ1000E1/E2) says the coils are 2.5 Ohms primary and the ballast resistor is 1.5 Ohms for a cumulative total 4 Ohms resistance. I can't confirm the correctness since neither set of Kaw coils I own (I have a 79 and an 80) tested to anything near the 2.5 Ohms... both sets had high resistance as did the ballast resistors so I tossed them in favor of one of your Dyna S, with matching Dyna wires and the 3 Ohms greenie Dyna coils. This stuff is so inexpensive these days, it hardly makes sense to fight with old ignition components unless you luck out and find some good stuff. I have bought several Kaw electronic ignitions off eBay (in my cheaper and less wise years) and none have ever been any good... there might be a reason why folks sell used electronic ignitions? Bwhahahaha

steell wrote:

But as far as I know the only KZ's with a ballast resister are certain years of KZ1000's, and he has a KZ900.

And I know that none of the KZ four stroke models had CDI ignition, although the two stroke triples did.

Ballast resisters fail by increasing resistance, not by decreasing it (it's the nature of their construction), so if a ballast resister fails you are going to get little or no current.

Steell, you are absolutely right, but the point I was trying to make is that if you don't check the ballastresistor (if there is one) you don't know if it is allright. So you can change the coils, but still have a problem with a weak spark because of a high total resistance of the new coil and old ballast resistor.
And I think that less parts (2 instead of 4) is better for reliability.

KZ1300 also have ballast resistors according to this:
www.kz1300.com/techfaq.html#cp2

That's where I read the CDI would fry if the resistance of the coils is too low...
What's the difference between a transistorized ignition and a CDI?

A lot of people are confused about the different types of ignition

An excellent explanation of how the different types work is at www.jetav8r.com/Vision/Ignition/CDI.html