1978 kz650 no spark on 2&3.

Getting my bike ready for spring since I never finished it last year before I got too busy. When I got the bike it had Dyna Electric ignition installed on stock coils. I have a 1984 KZ700 (or 750, I don't remember.) I knew that these models had electronic igntion and I'm constantly having spark issues anyway so I took the coils off of that bike and swapped them onto my '78 and rewired the connections for the coils. I was getting the best spark I had seen so far, very vibrant. Now, I can not get the 2&3 coil to spark on the 2&3 wire, even jumping it from the Dyna Ignition harness. I can get a very nice spark by plugging it into the 1&4 coil.

To recap: Good spark on 1&4 coil. No spark on 2&3 coil. 2&3 coil will spark very well if I swap to the 1&4 ground. Jumping to the Dyna harness as close as I can to the "points" did not fix my problem.

Using the sparkplug caps that came with the bike? If so, get new ones, as the 5000 ohm resistor that suppresses the RFI (Radio Frequency Interferrance) will go bad from heat, vibration & age. www.z1enterprises.com sells new ones(the sparkplug cap), also when installing the new caps, cut about 1/4" off the end, for a better connection.

Ignition Coils And Sparkplug Wire Choices

What came with the bike, were ignition coils that even when new were marginal, add years of cooking under the tank in the stop and go traffic, and the ignition coils will probably fail when hot.

Replacement coils can be bought at www.z1enterprises.com
I believe “Emgo” is the brand. They also carry the popular Dyna 2.2 and 3 ohm coils, along with replacement sparkplug wires.

Now, you have a choice on sparkplug wires:

1.Copper plug wires with no supression caps (the best choice, but will produce audio noise on Radio’s and TV’s). Not only do the copper core wires deliver better spark, they will also deliver a much longer lifespan - carbon core wires are prone to erratic spark delivery and early breakdown, & short lifespan.

2.Copper plug wires with supression caps (a built in 5000 ohm resistor, that can sometimes fail, like what came with the bike). These should be checked with a multimeter now and then, as heat can cause them to become intermittent.

3.Copper plug wires with no supression caps, but using resistor plugs(the “R” in the plug number).

4.Supression plug wires with no supression caps.

NEVER use resistor plugs combined with supression caps along with supression plug wires, as now there will be possibly three (3) sources of resistance in the secondary windings of the ignition coils, greatly reducing the spark energy.

Another choice is the Accel 3 ohm coils, with a similar, primary(small wire)electrical connection, using ring terminals as the Dyna ignition coils do. Whatever brand of coil you go with, make sure the primary wires will clear the mounting hardware, as the spacers come close, possibly blowing a fuse. Some riders have replaced the metal spacers with non conductive Nylon spacers, reducing the chance of an electrical problem.

7mm sparkplug wires will fit the stock ignition coils(if they have replaceable wires, indicated by screw off caps on the coils with ridges). The sparkplug wires fit into a port with a brass ”Stinger” that goes into the sparkplug wire or lead(the Brit’s. Canadians, and other countries call the sparkplug wires (“High Tension Leads”).

That 1984 KZ700or750 should have had 2.3 ohm coils. According to Dyna, you must use coils that are 3.0 ohms or higher. The lower resistance coils draw too much current through the Dyna ignition. The Dyna may be toast.

Ordered a new Dyna S. I'll update when it's on!

Got a new Dyna S and new Dyna coils put on this week. She runs a million times better. Better than it's ever ran since I've owned it.