Spark dies, then mysteriously returns. ICM prob?

otakar wrote:

The bike he has came with 2.2 Ohm coils from the factory with the factory electronic ignition.

Yes indeed, 2.2 ohms being unsuitable for Dyna-S designed for coils of at least 3 ohms resistance, regardless of whether the coils are stock or not.
(See installation wording underlined in red).

Good Fortune!

For what it's worth, I've been running a Dyna S ignition in my '78 KZ1000-A2 with the stock coils and wires since 1993. Have never had any problems with it. I couldn't find any info in the FSM as to what coils were used for that model.

Gman wrote:

For what it's worth, I've been running a Dyna S ignition in my '78 KZ1000-A2 with the stock coils and wires since 1993. Have never had any problems with it. I couldn't find any info in the FSM as to what coils were used for that model.

Z1~KZ900, 1977 KZ1000-A1 and 1978 KZ1000-A2 all had oem points ignition and used the same 3.2~4.8 ohm coils (suitable with Dyna-S ignition).

1979 KZ1000-A3 introduced the electronic ignition (with i.c. igniter) which used 1.2~1.9 ohm coils, plus a 1.5~1.9 ohm resistor.

Good Fortune!

After those in 1981 Kawasaki went to a new IC ignition that was 2.2 Ohms and used matching coils (2.2 Ohms) with no ballast resistor. The best IC ignition I believe is the GM module one that was designed by "Loudhvx" that uses the 2.2 Ohm coils. The Kawasaki OE ignition is the second best. and the Dyna comes in last, because it was designed as a "points'replacement" for the older (pre-1979) bikes. Obviously you can go with the high dollar ignitions that are available from MSD and Dyna which are VERY good. I know you had some problems with the OE ignition but you would have been better to get that running instead of replacing it with a Dyna.