Adapter circuit to use car tachometers on KZ's

Cheap tachometers for cars expect to get 1 pulse per every two crankshaft revolutions for each cylinder. This means, for a 4-cylinder car, it expects 2 pulses for every crank revolution.
On the KZ, that means it needs to get a pulse from each of the two coils for every crank revolution.

You can't simply connect the wires together. It requires a small adapter to add the pulses together.

And, as in many things related to ignition, the key to knowing how to add the pulses is the dwell.

The stock, electronic ignition uses a dwell less than 180 degrees.
The DYna S uses a dwell much higher than 180 degrees.






Unfortunately, for points, the dwell is right near 180 degrees, so the pulse adder is more complicated than the above circuits. I don't have one already designed and drawn up for points (as no one has needed one yet).

Thanks for posting! I assume it would be the same for the dyna 2000 as it is for the dyna S and dyna 3, am I correct?

Les

les holt wrote: Thanks for posting! I assume it would be the same for the dyna 2000 as it is for the dyna S and dyna 3, am I correct?

Les

I don't believe so. I would expect the Dyna 2000 to vary the dwell intelligently, since it is a digital microcontroller. That means there is a good chance the dwell will vary from much less than 180 degrees to over 180 degrees. So both of those adapter ciruits will likely not work with the Dyna 2000.

However, doens't the Dyna 2000 have a dedicated output port for a tach? If so, maybe it can be programmed for 2-pulses-per-rev?

You probably need to refer to the Dyna 2000 literature if you have it.

I'll give the directions a read tomorrow when I get back to the shop.
Thanks.

I will be saving this schematic for future reference.

Les

Here's a link to the Dyna 2000 pdf.
www.dynaonline.com/skins/downloads/instruct/DDK3-3.pdf

It appears it has exactly the tach output you would need.

Use the green tach wire.

I just dug out my paperwork on it not 5 minutes ago and read that. Jumped on here to confirm your thoughts.
Thanks again.

Les