What ohm Dyna coils for 80 KZ1000 electronic ign

Book says 1.7 ohm coils, can you use the Dyan red 1.5 ohm coils for 80 KZ1000 w/electronic factory ignition ?

Yes you can, but why? remove the Ballast Resistor, connect the two wires together and install 3 or 4 Ohm coils. They should be 3 Ohm but the Dyna Green coils mount really Funky, but the Accel 4 Ohm coils mount very logically. The Dyna 3 Ohm "green" coils will give the better performance.

Sounds like a plan where is the ballast resistor, built in to the wiring or a seperate piece ?

It is a separate piece and should be near the coils or under the left side cover. It is a ceramic little block, and has a plug with red and pink wires going to it.

I suspect there are some mistakes in the manuals from that era. My 550 factory manual lists the coils as 1.2 to 1.9 ohms. I know that is completely wrong. They are all in the 2.4 to 2.7 range, and were likely 2.3 ohms, originally, as spec'd in other manuals from that era. The range was given as 1.8 to 2.8 which puts 2.3 right in the middle.

So eliminate the ballast if it had any, then use the 2.2 ohm Dynas. 3.0 will also work, but I think the 2.2 will be better matched to the dwell.

The best way to tell what you have is to measure the coil's resistance on the primary side.

The Pre-"J" series 1000s were 3 Ohm systems. I went threw this wit a few coil manufacturers. Just like my 79 1300 was a 3 Ohm system. They have a totally different igniter from the one on my bike and they are not interchangeable.

But as long as the pickups and rotor are the same, they should be interchangeable. The wire connections may be different, but should be able to splice.

If the pickup coils or rotor slug are different it would be interesting to see what they look like.

On the typical factory ignition from 80 or so, the shape of the rotor is what determines the dwell. Notice the radius increases for about 120 degrees and reduces for 240 degrees on the slug as it rotates. That's what sets the limits for the dwell angle. (At lower RPMs the dwell angle reduces, but the upper limit is determined by that 120 degree shape.) If the rotor is the same, the dwell is the same (within some margin of error). The dwell determines what coils to use, so if the rotor and pickupos are the same, the 2.3 ohm (or 2.2 ohm) coils are what is best suited.

The 3 ohm system was probably just a slapdash measure until the proper coils were available in sufficient numbers. If a ballast was used in the 3-ohm system, then the coil was a low impedance coil. When you use a low resistance coil with a ballast, the required dwell time is actually lower (than what a 3-ohm coil would want) since the saturation time will be shorter. So even though the system appears to be a "3-ohm system", the dwell is actually designed for a lower resistance (or "impedance") coil. So if the ballast is to be eliminated, the coil should actually be lower than the sum of the ballast plus original coil. In other words, the system should be named for the coil resistance for which the dwell is a good match, not one for which the dwell plus a bllast is a good match. It's like apples and oranges.

Thanks guys, you are way to smart for me :blink: