Can I use dyna coils with points

As I am having mad problems with my bike and my spark is not adequate, I am looking to replace my coils as it is really the only part of the ignition system I have not replaced. Well, that and the starter. I am looking at the www.amazon.com/Dynatek-Miniature-Coil-Si...ils+%28Pair%29+DC3-2 and hope they will work with my points. Thanks.

You need to use the GREEN 3 ohm Dyna coils with points or the Dyna 'S' ignition.
Those 3 ohm mini coils will overheat on ignitions without dwell control which is why Dyna only recommend their use with the Dyna 2000 etc.

I think the points ignition uses 4.0 ohm coils, so if he went w the green Dyna coils, would he need to add a resistor or something?

Use 4-5 ohm coils with points. The green coils are 3 ohms and more appropriate for use with the OEM electronic ignition.

Poor spark is often traced to poor voltage at the coils, and/or worn out wire leads and caps. You can get new wires and caps from Z1 Enterprises for cheap so that that's a worthwhile experiment. If your harness has too much resistance you could try to clean the connectors, or set up a relay to feed power directly to the coils. You want to make sure to have at least 11 volts feeding the coils at all times.

If the only differenct between the coils is 1 ohm, a resistor in series with each coil should take care of that. If we are simplifying the coils to be ohmic devices at 4 Ohms we would have about 3 amps through the coils, so these would need to be pretty hefty resistors.

It's true you can add 1 Ohm in series with a three Ohm coil to make it safe to run (and restore the correct current draw) but it also wastes 25% of the energy because it means that instead of having 12V across the coil, you will have 9V due to the drop across the resistor. Sort of a "coil mod" in reverse. Reduces spark energy. Would be better just to run a four Ohm coil.

ewolpert wrote: If the only differenct between the coils is 1 ohm, a resistor in series with each coil should take care of that. If we are simplifying the coils to be ohmic devices at 4 Ohms we would have about 3 amps through the coils, so these would need to be pretty hefty resistors.

Power is current squared times resistance so it would be about 10Watt. Always use at least double the power rating, so it is a pretty large resistor.

It's true you can add 1 Ohm in series with a three Ohm coil to make it safe to run (and restore the correct current draw) but it also wastes 25% of the energy because it means that instead of having 12V across the coil, you will have 9V due to the across the resistor. Sort of a "coil mod" in reverse. Reduces spark energy. Would be better just to run a four Ohm coil.

I've already ordered 3ohm coils. I am not sure what the problem would be with those. I can assume the only issue would be the points themselves. I suppose the power draw on the battery could be an issue as it would be an increase of 2 Amps.

The green 3 ohm coils, used with points will shorten point life a little.
Dyna does not have 4 ohm coils, which would be what you'd want for stock points.
KZ650 owners, with points, report the black 5 ohm Dyna coil works well for points.
The Dyna gray 2.2 ohm coils would be the sesired coils for the OEM electronic ignition, but the green 3 ohm coils will work for that too.

For anyone who doesn't really know what ignition they may run in the future, the standard size, green, 3 ohm Dyna coils are about the best option (or the 3 ohm Accel Supercoils) since they can work for almost all of the common KZ ignitions (points, OEM electronic, Dyna III, and Dyna S). However, occasionally, KZ650's with 1-phase charging systems (usually 1978 and 1979) run into charging problems if they use the Dyna S with green 3 ohm coils, as it uses more power than the stock points system.

If you ordered those mini coils, you should cancel that, or return them.

And yes, as Zed mentioned, the mini-coils should only be used on systems with very efficient, and closely controlled dwell. Plus if you read the title of that link it says "single tower". If that is true, you don't want those coils at all on a KZ.

The photo in that Amazon link does not match the description. If you are going to return those coils, and you want to stick with points or Dyna S, then get the large, black 5-ohm, dual output, Dyna coils. You can use those 5 ohm coils with the Dyna S, and it will work better than points would with 5 ohm coils. Using 5 ohm coils with the Dyna S will not use as much current as the 3 ohm coils (with a Dyna S).

I am using 3 OHM coils with my Dyna S. They do take a lot more power. I didn't notice my low charging issues until I installed them. That, the extra lights and now a cam, my Reg/rect just gave out. The Z1 came with 5 OHM coils. My spark is much stronger but they draw more power doing it.
Steve

ewolpert wrote:

It's true you can add 1 Ohm in series with a three Ohm coil to make it safe to run (and restore the correct current draw) but it also wastes 25% of the energy because it means that instead of having 12V across the coil, you will have 9V due to the across the resistor. Sort of a "coil mod" in reverse. Reduces spark energy. Would be better just to run a four Ohm coil.

I've already ordered 3ohm coils. I am not sure what the problem would be with those.

The coils will burn up and have a very short life. Electronic ignitions have a lower duty cycle so the average current is lower compared to points. And with points, you can turn the key on and if the points happen to be closed, the coil will cook itself.

I use Dyna 3 Ohm coils and points, but I have also done the following mods to the ignition system.
- Wiredgeorge Coil Wiring Modification (increases voltage to the primary coil)
- Copper Spark Plug Leads (last longer than carbon leads)
- Primary Coil Ballast Resistor, 17W 1 Ohm Resistors (protects coil from excessive current)
- Spark Plugs, NGK, BR7EIX, Iridium, 5k Ohms (or B7ES plugs and 5 kOhm plug caps, if desired)
- Spark Plug Cap, NGK, LZFH, Zero Ohms
- 'Hondaman', Transistorized Ignition for Dual Points (points retained and draws less current than Dyna S)

I've kept to the original primary coil resistance of 4 Ohms and also as close to the 23 kOhms original resistance on the secondary as I could manage. Note, the total secondary resistance is the coil resistance plus the resistance of both plugs (14 kOhms + 10(2x5) kOhms = 24 kOhms).

The transistorised ignition draws hardly any current and is less strain on the charging/battery system and so more current for the headlight, which I have on day or night.

The 3 Ohm Dyna coils are a higher energy coil than the original 4 Ohm coils, so you would get a higher voltage spark if they were connected directly to the 12V supply, but they would run too hot, which is not recommended, hence the 1 ohm ballast resistor. However they still work very well with the ballast resistor.

The mod that made the most difference initially was the wiredgeorge mod. Before this my bike was a pig to start and took a long time to warm up.

Anyway, this is what I have done and it works fine for what I want, which is a low current, reliable system.