Late model electronic ignition... will it fit on

On my Z1 and KZ900, I first replaced the points ignitions with Dyna-S, and kept using the oem coils (with permanently implanted spark plug wires), which performed okay until either the coils gave up or the old hardened plug wires started leaking or the plug caps went bad. All of which issues were resolved by installing the green Dyna 3 ohm coils (which I understand are designed to work with the Dyna-S ignition), and Dyna plug wires (delivered with caps already attached).

I agree with otakar about keeping the ballast resistor when also keeping the lower ohm oem coils incident to replacing an oem electronic ignition with Dyna-S ignition.

Good Luck!

otakar wrote:

...I don't know why but my 78 Z1R came with ballast resistors. They are not even shown in the wiring diagram in the manual.

My FSM wiring diagram for 1978 KZ1000-D1 also shows ordinary points ignition without ballast resistor or igniter. And wiring diagram for 1979 KZ1000-D2 shows electronic ignition pickup coils (instead of points) plus igniter and ballast resistor.

It's interesting that some of the D1's came with oem ballast resistors, which presumably also had the lower ohm coils used with 1979's electronic ignition.

Good Luck!

so I can buy the dyna S and install it on my 1977 bike and everything will be fine? Am I understanding that I will have weaker spark though?

This is correct.

Just to re-hash what Otakar, Patton, and Bill have said:


tomcat wrote:

so I can buy the dyna S and install it on my 1977 bike and everything will be fine? ?

Yes, but the Dyna will require about an extra 4 amps of charging system power. Your bike should be able to handle that with no problem.

tomcat wrote:

Am I understanding that I will have weaker spark though?

Yes, with 4-ohm coils you will have very slightly weaker spark than with 3-ohm coils, but not enough that you would ever notice as long as the bike is tuned well and in good condition, assuming your 4-ohm coils are good.

However, the spark with 4-ohm coils and Dyna ignition will still be much better than what you had with the points. There is really no need to get rid of the 4-ohm coils if they are in good condition. Also, the 4-ohm coils will save your charging system a few amps over 3-ohm coils.

The only problem with 30 year old coils is that they get tiny cracks which let in moisture and can lead to failure, unexpectedly, and can leave you stranded.

You can get the Dyna now, and possibly coils later.

If you use a Kawasaki electronic ignition, you will need new coils now to get full spark.

Wit the 4 Ohm coils, You will not have any problems for normal riding. You MAY however experience a decrease in fuel economy and if you really get on it, you might experience what is known as "spark blowout" at higher RPM. This would result in the bike shutting down unexpectedly at high RPM. Once the RPM drops again the bike can be restarted normally. I am just saying this because i don't want you to get panicked if this happens. There is nothing wrong it is just the nature of the beast with the higher resistance coils. I have had it happen to me quite a few times until I went to the 3Ohm coils.

Otto

otakar wrote:

Wit the 4 Ohm coils, You will not have any problems for normal riding. You MAY however experience a decrease in fuel economy and if you really get on it, you might experience what is known as "spark blowout" at higher RPM. This would result in the bike shutting down unexpectedly at high RPM. Once the RPM drops again the bike can be restarted normally. I am just saying this because i don't want you to get panicked if this happens. There is nothing wrong it is just the nature of the beast with the higher resistance coils. I have had it happen to me quite a few times until I went to the 3Ohm coils.

Otto

If it doesn't happen with points, why would it happen with the Dyna?

Why would the bike shutdown? Do you mean that something gets permanently damaged during the "blowout"? If so, why only with the Dyna ignition and not the points?

The Dyna gives nearly double the dwell of points and most likely can withstand a much higher primary voltage spike. This would have twice the spark energy with less chance of the spark failure due to primary bleed-off. With no primary bleed-off, the spark would have to discharge through the secondary, and thus throuigh the spark plug, unless the coil is failed or the plug wires are leaking.

Because the points are set up for the 4 Ohm Coils the Dyna is set up for 3 Ohm coils. This gives a weaker spark. I used to experience this on my Z1R all the time until I changed to 3Ohm "Blue Goose" coils back in the late 70s. There is no damage done. What happens, is that the spark is week enough that the turbulence in the cylinder can actually blow it out. Once the turbulence decreases sufficiently, the spark will come back. If you do not take the bike out of gear, the bike will start by itself. If you do the bike will have to be restarted. This first scared the hell out of me when it happened the first couple times, until I figured out what it was.

I'm not sure what you mean by "set up for". The Dyna is designed to operate like a switch. The points actually are a switch. They both do the same thing which is to ground the negative side of the coil. Operationally, the only difference is the length of time they ground the coil, and how much primary voltage they can withstand. The points ground the coil for 180 degrees of crank rotation. The Dyna grounds the points for nearly 360 degrees of crank rotation. Typically, the electronic ignition will handle more primary voltage.

The amount of spark energy the coil can store increases with the primary current up to a point. The primary current increases slowly up until it reaches "current-saturation". This is because the coil has inductance. Inductance prevents the current in the coil from increasing instantly. Since the primary current needs time to increase, more dwell gives more time for the current to increase. "Current saturation" is when the current in the coil reaches a level where the current is only limited by the DC resistance of the primary windings. Any more dwell time beyond that is only wasted. The current is at its maximum and any further dwell time will only heat the coil and produce no extra spark energy.

When the dwell time is over, the points or Dyna simply cuts the current off. Since coil current can't stop instantly, a large voltage is produced in the primary to force the current to continue. With points, a condenser absorbs this high voltage spike so the points won't arc. With the Dyna, most likely, a Zener diode bleeds off a little voltage to protect the transistor. In both systems, the high primary spike relates to a 100 times higher voltage on the secondary and a spark is generated.

The points use a 4-ohm coil because with lower resistance, the points will pit too soon. The Dyna uses an output transistor to emulate a simple switch. The transistor has a limit to how much current it can safely handle. The limit on the Dyna must be about 5 amps since they specify 3 ohms as a minimum. (15v divided by 5 amps would be 3 ohms.) That is why 3-ohms is specified for the Dyna ignition. It simply a safety limit, not an impedance matching situation.

Since both ignitions do the same thing, the only differences are the dwell angle, the ability to stop primary voltage, and the safe, maximum current level. Of those, because the Dyna gives twice the dwell-angle, it also gives twice the dwell-time for a given RPM. This is the significant difference which allows for much more spark energy at very high RPMs. At lower RPMs, the extra dwell does not give any advantage since there is already way too much dwell time at low RPMs. In fact, at low RPMs the Dyna just heats up the coils more than the points will.

Since the dwell is twice as long on the Dyna, regardless of which coil is used, the Dyna has the potential to provide more spark energy than the points. At worst, it will be the same as points (this is when 180 degrees allows current saturation, any more dwell will produce the same spark energy).

Here are some notes I've been working on to analyze and optimize ignitions to provide adequate dwell efficiently. The Dyna uses a fixed dwell angle, but you really want a variable dwell angle in order to prevent overheating a coil and prevent wasting power.

CoilSpecsGpzHeiCalculations.doc

Also, here is reprint of my measurements on various coil charge rates. This chart shows each coil's rate of current increase when a voltage is applied ot the coil (this is the same as when the points are closed).