No spark at any plug. Bad ignitor?

Presupposing that the coils are good, with battery+ voltage being supplied to the coils, can test integrity of the secondary loop for each coil by tap-tap-tapping a grounded wire against its primary terminal, which replicates grounding and ungrounding of the coil, which is supposed to send surges of high tension voltage through the secondary loop (including sparks as the high tension voltage jumps across the tips of the plugs).

This test by-passes the igniter and pick-up coils that normally operate to ground and unground the ignition coil as the crankshaft rotates.

If no plug spark is produced when the grounded coil is ungrounded (by removing its signal/trigger wire from its primary terminal), there's likely a failure for whatever reason in the secondary loop.





Here's as example of a break in the secondary loop whereby neither plug will fire.



There are also several other maladies that can cause a break in the secondary loop, such as a bad connection between plug wire and coil, a bad connection between plug wire and the plug boot/cap, a defective plug boot/cap, a bad connection between plug boot/cap and the plug, a defective plug, or a short from a plug wire to the engine (perhaps due to an old worn cracked plug wire).

Good Fortune!

Edited to assure that the "tap-tap" wire is a length of owner-supplied ground wire..

Thanks for all the information @Patton. I previously tried testing the coil similarly, but started with the ground/signal wire detached and then grounded it on a bolt. I could only get a spark where I was grounding it, not at the plug, but from what I read this is often the case. I'll give your method a try tonight and let you know what I get.

mnike000 wrote: Thanks for all the information @Patton. I previously tried testing the coil similarly, but started with the ground/signal wire detached and then grounded it on a bolt. I could only get a spark where I was grounding it, not at the plug, but from what I read this is often the case. I'll give your method a try tonight and let you know what I get.

I edited the text in my post to say a wire from ground can be tap-tap-tapped against the coil's primary terminal to replicate repetitive grounding and ungrounding the coil's primary winding. And the same effect could be had by tap-tap-tapping a wire from the coil's primary terminal to an engine bolt or the engine head or the negative battery terminal or any other ground (which I believe is what you did).

It is the ungrounding of the coil primary that creates the high tension surge throughout the secondary loop. The plugs should spark upon interruption of the ground.

The test assumes that both spark plugs in the loop are grounded (probably just laid on the engine so the sparks will be visible). Actually, the plug bases could just be tapped together so as to complete the loop without needing the engine head.

Good Fortune!

Ah I see. Thanks for the clarification. So in that case, since i was only getting a spark at the bolt I was tapping against and not the spark plug, does that indicate that the secondary windings are bad? I didn't get a chance to do anything with it this evening, but I'm gonna at least try the other coil (only did one last time) tomorrow. Thanks again for your help @Patton

If plug wires are removeable from the coil, could ohm-test the secondary wiring inside the coil.

If plug wires are non-removeable from the coil, could ohm-test between plug caps or between ends of plug wires.

I could be wrong, but am at this stage more suspicious of something else besides both coils having simultaneously failed. Am thinking a set of relatively inexpensive new Dyna plug wires with integrated caps could resolve any secondary loop problems beyond the coil terminals.

Good Fortune!

If this occurred after a crash, it is unlikely to be the components. You have a wiring issue. Igniters do fail, just not that often. If you noticed this problem after a dump, it is logical to assume wiring is snapped or grounded to fault somewhere. Do you have a manual? All the testing procedures and wiring diagram is there. I would strip out the wiring and reconnect it all with clean contacts and all wire inspected. If it ran before the dump, its wiring, unless the crash made physical damage to the ignition side cover - as in tore it off. Good luck. R

Must watch really close to see which way the spark is arcing across the business end of the plug. :woohoo:

Good Fortune!

Hey guys just wanted to drop in and let you know that some things came up and I haven't even been around the bike in a few days, but I appreciate your help and will let you know what I find as soon as I am able!

mnike000 wrote: Thanks for all the information @Patton. I previously tried testing the coil similarly, but started with the ground/signal wire detached and then grounded it on a bolt. I could only get a spark where I was grounding it, not at the plug, but from what I read this is often the case. I'll give your method a try tonight and let you know what I get.

On some coils, you will need a condenser to produce a spark by making/breaking a primary connection, otherwise all you get is a spark at point of contact of the wire. I've found this is the case with the KZ electronic ignition coils, but not always. Other conditions may effect this as well, like barometric pressure, humidity, etc.

BTW, thanks for the great graphics Patton, those will help a lot of people get the idea.

In case anyone is interested, I have recently posted a brief synopsis of the ignition types and coils types you may come across in dealing with motorcycles and other small motors. It's not casual reading, and not necessarily relevant to this thread, but just for anyone curious why so many coils seems so different.
s3.amazonaws.com/gpzweb/Ignition/Ignitio...esAndCoilWiring.html