IC Ignitor test

I have an '80 KZ750 LTD that has been Having running issues.

1: It did run very well
2: lost spark on 2-3 cylinder, intermittently at first. The engine would lose power, then it would unexpectedly come back, probably due to vibes. Voltage is present at the coil. Verified plugs are not bent to ground. verified proper coil windings (hi and low) resistance.
3:while running (on 1-4 only) I was cruising around with the test light, and shaking wires looking for an intermittent short. At the pickup coils, I was checking for voltage interruption with the light. Shorting the yellow wire suddenly caused the coil to function. I shut off the bike to look for the open wire.
4:Now the MC will not start at all and I have no fire at either coil (but still have voltage present at both)

This bike has new plugs and resistor caps. New battery, replaced left coil (2-3) with salvage, old one was bad before.
I know this is an old subject, but trying to skim through all the old threads takes hours sometimes.

Ok, now I have it running on 1-4 again. Someone had previously ugly spliced the coil side of the IG box with butt splices. Full of corrosion. fixed that.

When I started messing around with it, I grounded the red wire on the trigger and the engie came alive again. Un-pinned the red wire from the plug and found that when I grounded the Hall pickup red wire, voila...

Also, I believe the cause for this problem is that at some point prior to my getting it, looks like the battery was boiled out all over the frame, wiring and all the stuff on the left of the battery box.

So, what, if anything, will be ruined by running this red wire to ground bypassing the IC IG box? The local bike salvage shop wants $75 USD + tax for a used one.
Wish me luck:woohoo:

Assuming you have the original stock ignition: Grounding the red wire would probably alter the dwell, longer or shorter, I'm not sure. It could mean the red wire is broken inside the igniter box. The pickups are just little coils of wire, so grounding the red wire restored continuity, but will alter the bias which affects the dwell.

You can make a new igniter for cheap:
home.comcast.net/~loudgpz/GPZweb/Ignition/GPZgmHEImod.html

You might have a bad pulsing coil. Figure out which two wires are for 1/4 and which two are for 2/3. When it dyes, unplug the four pin connector to the IC box and measure the coils and see if they read between 360-540 Ohms.

Black/blue is for 1/4 and yellow/red is for 2/3. Since the bike is running, I would assume the pickup is good, just not the one connection in the IC igniter.

But ohming them out like Otto says would be a good idea.

Thanks for the tips. I already did ohm out the pickup coils, both were in range. Pretty sure the wire is open inside the Ic box.
I cut the wire between the plug and the box, and ran a ground wire in the red wire circut. Not sure what this will do in the long run, but in the meantime it runs awsome.
If it does eventually completely fail, I will build a HEI box myself, looks cool and I'm pretty sure I can get the HEI's for free or for just a couple of dollars each.

kind of dumb that the wiring comes out of the top of the IC Ignition box , instead of the bottom to keep fluids out.

I bought a couple ignitors on eBay as spares. I bought them for about $25 each. What you should do is get rid of the OE coils ( and ballast resistor if you have one) and install a set of Dyna 2.2 Ohm Gray coils.

Have you ever considered potting your diode/resistor circit in epoxy resin or an acrylic caulking? I would imagine if you live somewhere with harsh weather it would help protect it from the environment. I may have to try one of these for the next 2 stroke to come along with a bad brain.

wargoth wrote:

Have you ever considered potting your diode/resistor circit in epoxy resin or an acrylic caulking? I would imagine if you live somewhere with harsh weather it would help protect it from the environment. I may have to try one of these for the next 2 stroke to come along with a bad brain.

I've built several other bike-related circuits and have used silicone caulk. Be careful, though, it must be 100% silicone caulk. Latex conducts electricity slightly, and will screw up circuits.

I've also used Great Stuff expanding urethane foam. That works well if your circuit is enclosed in a box and it's much lighter, but a lot more messy.

So far the foam and 100% silicone work really well against weather.

The first prototype igniter I made just has electrical tape wrapped around the parts. They are not even mounted to a board... just soldered wire to wire and wrapped. That was meant to be a temporary trial, but it's been 5 years and no problems so far including some short, hard rainstorm rides.

I'm just starting some experiments with a 7-pin HEI module to see if it might work without any extra parts and/or possibly be able to employ a spark delay for starting. It will probably be a while, though. These things take time.

The two-stroke Kaws used actual CDI ignitions. I think this is why so many sources incorrectly call the KZ ignitions CDI. The HEI is only for flyback (aka transistorized Kettering) ignitions, which is what came on all KZ's.