TOPIC:

Hey all, recently came across a Dyna S ignition in a random box at a garage sale. Looks to be off a 900/1000. Any way to test if it works off the bike without frying it?

I don't think so. The magnet in the center piece needs to be rotating to allow the coils to see voltage.

Looks like you missing a piece. With rotor you can test it.

.As others have indicated you need the magnet that fits over the rotor to test fully. But there are some tests you can without it. Not sure they will tell you all that you are looking for though.

I have attached testing doc from Dyna .

The magnet does not need to be rotating. It's a Hall-effect sensor, so only needs a magnet in proximity...moving or not. Just put a magnet near the pickup sensor. And it has to be the correct polarity . A small pill-shaped neodymium should be more than powerful enough to activate the igniter. If it doesn't work, just flip the magnet over.

To prevent overheating coils or frying the igniter, just use a turn signal bulb in place of each coil. Each light will turn on when the magnet is away from its respective pickup. When the magnet approaches the appropriate pickup, the light bulb will turn off.

Since you won't be using much power with the light bulbs, you can just use a stand-alone motorcycle or car battery as long as it has a full 12v on it.

Here is the wiring. Not shown is that the plate of the Dyna S must be grounded to the battery.



If it works with the bulbs, then next is to try with real coils. Only connect one coil at a time and make sure there is a path for the spark to go from one plug wire to the other. The coils don't need to be mounted or grounded... just wired as shown in the diagram and with the plate of the Dyna S grounded to the battery as mentioned. Don't leave the battery connected for more than a few seconds at a time when using it with real coils. You can burn out the Dyna S or overheat a coil if it's left connected too long. And of course, the coils must be 3-ohm or greater.

Thanks for the responses guys, I may replace the one (known good) in my running bike to test it. Looks like Z1 Ent. sells the magnet only so if it works I can make a complete set to use on a future project or sell it on to someone here who needs one.

So, the pickup of a Dyna ignition is a magnet opening and closing a switch, and not a pickup coil generating an electrical impulse?
Am I correct at assume pulser/pickup coils on most bikes use the magnet passing by them to generate a voltage, are not a magnetic switch?

The Dyna S pickup is a Hall-effect sensor. The rotor has a magnet embedded in it, so the moving part is the magnet. The Hall sensor is a semiconductor device making use of the Hall-effect, which is based on a magnetic field deflecting charges (in an electric current).

The common Kz electronic ignition uses a variable reluctance system. The pickup is just a coil of wire with an integral magnet, so the magnet here is stationary. The rotor (aka reluctor) is just a ring of iron specially shaped to produced the desired signal in the coil of wire. This system is similar to an electric guitar where the pickup is a coil of wire with a magnet in or near it, and the string is just some ferrous metal. Most car electronic ignitions from the era are very similar to this system. This system is a trasistorized version of a Kettering ignition. A Kettering ignition is the traditional coil and points ignition found on early Kz's and many muscle cars from the 60's and earlier that most of us are familiar with. It can have other names. Sometimes it's referred to as "inductive", or "flyback".

I like the term "Kettering" because it's more specific. Other types of ignition use a flyback effect, or inductive effect, so those terms can be slightly ambiguous.

Both of the above systems are used to control a powerful "switch" which historically was a Darlington-pair transistor, but nowadays is more likely an IGBT (insulated-gate bipolar-transistor). The switch simply turns the coil current on or off, but with special properties to handle very high voltage spikes and some have the ability to limit the current if setup up to do so.

Another system popular during that time was CDI. That is,capacitive discharge ignition. These systems used coils of wires as a pickup, but also used rotating magnets to charge the capacitor and trigger the ignition.

So there are many variations of magnets, coils, sensors etc. (not to mention optical-based systems) that can be found on vehicles from the last 50 years.

I should add, that among those variation, there does exist a Kettering system using a coil-pickup with a rotating magnet. I think someone emailed me with a two-stroke boat motor, maybe a Suzuki or Yamaha, which used this combination. So it's not restricted only to CDI systems.

loudhvx wrote: Don't leave the battery connected for more than a few seconds at a time when using it with real coils. You can burn out the Dyna S or overheat a coil if it's left connected too long. And of course, the coils must be 3-ohm or greater.

It seems running with a higher ohm coil would be safer. What is the down side? Weaker spark?

ckahleer wrote:

loudhvx wrote: Don't leave the battery connected for more than a few seconds at a time when using it with real coils. You can burn out the Dyna S or overheat a coil if it's left connected too long. And of course, the coils must be 3-ohm or greater.

It seems running with a higher ohm coil would be safer. What is the down side? Weaker spark?

Here’s the answer I’d like to see. Coils are available in different Ohms. Why?

Yes, running a higher resistance coil is always safer for the coil and ignition because of lower current, but it's not necessarily safer for the engine if using that coil causes the spark to fail.

And so yes, the potential downside is weaker spark or failed spark.

But this is not to say higher resistance coils necessarily produce a weaker spark. It's because the available dwell time might not be sufficient for that particular coil to charge fully to produce a strong spark. In fact, higher resistance/inductance coils may produce more spark energy than a low resistance/inductance coil, depending on how much dwell is provided.

Dwell time is the time during which the coil charges up with energy.
Dwell angle (in a Kz) is the number of degrees of crank rotation during which the dwell is active.
On a system like points or the Dyna S, the dwell angle is fixed, so the dwell time varies with RPM.
Higher RPM has much less dwell time than idle. Idle has very long dwell time.

A coil that charges quickly will usually have lower resistance and lower inductance.
A coil that charges slowly will usually have higher resistance and higher inductance.

So when we talk about the resistance of a coil, we are using that to also imply the inductance of a coil, and thus we are really talking about the ability of a coil to charge quickly or not.

If you have a very long dwell, you can use a "slow" coil and get plenty of spark energy.
If you use a "fast" coil you will be in danger of melting the coil or the igniter. The extra dwell time only translates to heat generation in the coil and igniter, not extra spark energy.

If you have a very short dwell, you will need a "fast" coil to get plenty of spark energy.
If you use a "slow" coil you will likely have weak spark or fail to spark at all, especially at higher RPMs.

So as in most things, it's about finding the proper matched combination of parts.

The Dyna S was designed as a replacement for points on motorcycles which typically have very long dwell compared to a car. This is why motorcycles with points came with "slow" coils. Here I mean anything 3 ohms or higher as "slow". The Kz's with points came with coils that were basically 4 ohms. The Dyna S nearly doubles the dwell time compared to points (on a Kz), so the dwell will be far more than adequate for 4 ohm coils and even 5 ohm coils. And since Dyna designed it to handle the current of a 3 ohm coil, you have many options available. There is a chance that 3 ohm coils might give better spark at very high RPMs, but then at idle it will be very inefficient and may drain battery power and generate more heat. It's a tradeoff.

Some people use the Dyna S with 5 ohm coils and have never reported any problems.
Some people use the Dyna S with 4 ohm, stock coils and have no problems as long as the coils are in good condition (not too old).
Some people use the Dyna S with 3 ohm coils and have never reported any problems.

A very small number of people have reported charging issues when converting to a Dyna S and 3 ohm coils. Of those, more were '78 and '79 Kz650 owners than any other Kz, though it has shown up on a tiny handful of other Kz models.

Often the fix was to convert to 3-phase, or use a stock ignition system. The stock Kawasaki Kz electronic ignition is far more efficient than the Dyna S, and thus uses less power. Most people opt to convert because it's getting harder to find good, working factory ignition systems for Kz's.

So to answer Mikaw's question:
Cars with distributors have very little time between spark events to charge a coil because that single coil has to fire multiple times for every crank revolution. To do this they need a coil that charges fast. Typically they would be in the 1 ohm range, but could be lower or slightly higher. But as mentioned, this is not exactly safe because at low RPMs, the extra dwell leads to heat in the coil and reduces longevity. The extra current also greatly reduces the life of the points. The classic solution is to use a resistance-changing ballast resistor, and a special circuit during startup to bypass the resistor.

Well, this is not easy to implement on a kickstart motorcycle since you are not turning any switches while kickstarting. So to eliminate the distributor, and simplify the circuitry, they decided to just use two slow coils. This eliminates overheating issues and ballasts as well. So Kz points systems use 4 ohm coils and this is a good match for about a 180 degree crank rotation for dwell. This also gives good points life by having such a low current. The 4 ohm coil still charges fast enough to give good spark up to about 10,000 RPM.

When Kawasaki designed the electronic ignition, they figured out they could save some power, and also eliminate crosstalk between coil circuits by reducing the dwell to about 100 to 120 degrees. This required faster coils. The best match was found to be about 2.3 ohms. When their first system came out, the coils were not available so they used much lower resistance coils and added a resistor to make up the difference. That is why some Kz1000's had ballast resistors. They can be eliminated when the coils are replaced with 2.3 ohm coils. So that is why we have 2.3 ohm coils or a few, rare 1 ohm-ish coils.

Dyna decided to make 5 ohm coils as replacements for points coils. In order to not burn out points on bikes that use long dwell, they made them 5 ohms, but they work pretty well in place of 4 ohm coils. They had to make a single coil to fit on various makes and models, so there is always a compromise with that.

Then Dyna also makes 3 ohm coils which work on the Kz electronic systems and will also work for the Dyna S. Again it's a single coil to fit a wide range of uses, so that's why it exists.

Wow... thank you.

So to simplify things,maybe. Street riders that typically stay in the lower to mid rpm should use a “slower” coil to increase life at longer dwell time. Racers always in the upper rpm are better with “fast” coils because dwell time is shorter. ???

I have an older set of CirCycle 4 Ohms with a Dyna S on my ‘78 Kz1000 Ltd. No problems for me so far.