Ignition Module For 1981 Kawasaki GPZ550 Using HEI Modules
Designed by Louis Dudzik 8/05

This project is an ignition module designed to replace the stock unit for a 1981 Kawasaki GPZ550 motorcycle. It uses two GM HEI ignitor modules. The parts for this project should not cost much more than $35. This module is designed to work with the stock inductive pickups and the stock spark coils. Aftermarket coils can be used as long as the primary side's resistance is not less than 2.4 Ohms. This module will also work as a replacement for other Kawasaki motorcycles that use the same stock unit as the GPZ550. Here is what they look like:

Click this for my notes and compatability cross-reference info on the stock Kawasaki KZ electronic ignitions. GPZstockIgnitionNotes.txt

Click this for my notes on the stock Kawasaki KZ electronic ignition's RELUCTOR waveform. GPZreluctorWave.gif

Because the GPZ550 has an inline, 4-cylinder engine, it requires two spark coils, two pickups, and thus, two igniter circuits. This replacement module (as well as the stock unit) actually contains two separate ignition circuits using two HEI modules acting independently. The Wells model DR100 or Niehoff model DR400cs seem to be the same unit. These are what the HEI modules look like:

Click this for my notes on 4-pin GM HEI ignition modules. Hei4pinGmIgnitionNotes.txt

The construction is simple, but first you have to clip off the two locator pins on the bottom of the modules.

Then just mount the two modules on to an aluminum plate using the supplied thermal gel and appropriate bolts. The plate needs to be at least 1/8 inch thick to be rigid. It should probably have at least about 9 square inches of surface area for adequate cooling. (It only gets slightly warm). The bolts will act as the ground connection. Next solder or use connectors to attach the wires. The 3 external components can simply be soldered and wrapped in tape. Make sure the polarity is correct on the two diodes by paying attention to the stripe on the diodes. The resistor can go either way.

Here is what the somewhat crude and ugly prototype looks like on my bike:

The module was installed in 8/05. The module currently (as of 8/07) has several thousand miles on it. If any reliability issues come up, I will update this page.

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Here is a diagram for a KZ twin version. This is for an 82 KZ750 m1 csr twin. It can be used on some KZ400's and KZ440's as well, if they have the mechanical advancer with reluctor rotor and relutctor pickup.