No Spark

I have no spark at the plug on my kz900ltd. I did a search on "no spark" and found some useful stuff. Here is where I am at:
I have a dyna S ignition and dyna coils with yellow wires to +12 and green and black wires to the dyna S ignition. I installed them 2 yrs ago (or 500 miles ago, didn't ride last year at all #@$%@#$.) via the wiredgeorge method with the relay.

Both coils are at 3.5ohms and 14.4kohms for the primary and secondary. I get 12.3V on the green/black and yellow wires with the key 'on'. It drops to 10.1V when cranking. I put a grounded wire close to the coil connection on the coils while crankin. No spark on any of the four connections. Thanks to those who posted this info in the past.

My Q's are: How can I tell if the Dyna S is working? Is it possible to measure an AC voltage across the 3.5ohm drop when cranking the engine to check if current is flowing? I would think you could if there is some current running through it. Or, can you tell somehow if the dyna S is grounding the green/black wires?

Questions, please, to confirm the existing situation. Is there battery voltage to both coils with constant zero voltage from both coils to the plugs? Seems odd that both Dyna pickups or coils would fail simultaneously. When installing the Dyna ignition and coils, were new Dyna plug wires and caps also installed? Maybe I'm misreading the information provided.

Yes, Patton, both coils are getting 12V and there is no spark to the plugs. Also, both coils have no shorts. I cannot see how it would be the coils. I think it is the Dyna S ignition, but that too is relatively new. I just don't know how to check it. New plug wires were installed but there is no spark right out of the coils, so it is not the plug wires.

I tried to be clear, but it is sort of all convoluted.

Post edited by: Ray J, at: 2007/05/11 21:46

If not already done, could use ohmmeter to check continuity of wire from left coil to left Dyna module and continuity of wire from right coil to right Dyna S module. This would at least verify connections of trigger wires from coils to Dyna modules. Still seems unusual that both Dyna modules would simultaneously fail. Would think one of the modules would remain operational even if the other failed. Has the magnet spot on the Dyna rotor been cleaned? Have the pickup units on both Dyna modules been cleaned?

My understanding is that when the magnet on the Dyna rotor interfaces with the pickup unit on the module it serves the same purpose as opening a set of points to interrupt the ground thereby forcing voltage from secondary coil winding to pass through the plug wires and plugs to ground. (I could be wrong, and wouldn't be the first time. )

Maybe the magnet on the Dyna rotor is defective. Would check to see if it's still "magnetic." If no magnetism, am guessing neither module would operate.

Sorry I don't have a better and more direct answer to your good question. If the old points plate is still available, it could be reinstalled temporarily to verify proper operation of the system except for the Dyna magnet and modules.

Hoping for you a successful repair.

Post edited by: Patton, at: 2007/05/11 22:51

Post edited by: Patton, at: 2007/05/11 23:06

Thanks, Patton. I don't have the old points, etc. But I will mess with the magnet tomorrow and see what's what. I assume there is no ground wire to check from the Dyna S, that the screws ground it. I'll let you know how things go.

Am still thinking about this.

The red/yellow wire feeds positive battery voltage to both coils. The other coil screws are the negatives, left coil negative going to left Dyna module and right coil negative going to right Dyna module.

Found these excerpts in an old Dyna trouble shooting guide:
With rotor magnet pointing away from modules (magnet in either up or down position), turn ignition on, measure voltage between coil positive (red/yellow wire screw) and ground -- should be close to battery voltage. Now measure between each coil negative terminal and ground -- should be about 0.8 to 1.4 volts with magnet pointed away from modules, and then up to battery voltage when the magnet interfaces with the module sensor. This indicates the module is switching on and off and probably working okay. Gap between the rotor and sensor should be between .025" and .040". Larger gaps may cause the module not to switch. Also, the voltage may stay low if the output is shorted.

Hope this helps.

Call dyna, or go to the web site I think its in the installation section, there is a test for the system.
I had a issue with mine talked to them, found a bad connection, but they will stand behind the system, even if it is out of warranty they will upgrade it for a small fee, cant ask much more than that

The Dyna S pickup modules needs 12V supply to function - you may have a bad connection where the power wire (red) ties into the harness.

Check this thread , the Dyna S test sheets are at the bottom of it.

Post edited by: OnkelB, at: 2007/05/12 10:42

OnkelB wrote:

The Dyna S pickup modules needs 12V supply to function - you may have a bad connection where the power wire (red) ties into the harness....

OnkelB is correct.

The Dyna S is supplied with a splice connector to tap its red wire into a switched 12 volt bike harness wire (such as the yellow/red on '76KZ900 under the tank that splits off to both coils). Have often heard it best to solder the tap joint instead of using the splice connector.

If the tap joint is good, there might be a break in the red wire between the tap and the Dyna module. Could use an ohmmeter to check continuity in red wire. Probably need a needle to pierce red wire insulation at module end for ohmmeter connection.

Spark!!!

Thanks for the help. It turns out both wires from the coils to the dyna were open. The wires must have gotten yanked pretty hard at one point. The bullet connectors connecting the dyna s wires to the wires coming out of my coils were pulled out, but I had put some heat-shrink tubing over them, so the connections looked straight. It wasn't until I started measuring voltages at the dyna s that I found the opens.

Thanks again... It runs, but on only three cylinders.