Zephyr 750 Ignition

I am having some problems with the ignition on my current Zephyr project. If anyone knows any good resources/forums for the Zephyr 750 please let me know. 

When I tried to start the engine after a rebuild there was no spark. I had completely replaced the electronics with a unit very similar to motogadgets M-Unit (the B-Box from Axel Joost - elektronikbox.de). 
I have since found out that the grey wire from the ignition to the ignitor is basically an anti-theft device. It's supposed to be connected to the battery positive through a resistor in the ignition unit that drops the volts to a certain level. If the voltage on the grey wire is incorrect it won't spark.

My first problem is that I removed the grey and green/black wires from the ignitor connector - the grey looks like it dead ends in the circuit diagram and the green/black is used for the starter circuit relay which I had replaced. Now I'm no longer sure which goes where 

The next problem is that the grey wire measures 12V when I connect it up to the ignition. Resistance between the white (directly from the battery positive) and grey wires is about 100 Ohms but the voltage doesn't seem to drop when I connect it all up...

The third problem is that I think I have fried the ignitor. I did the resistance tests from the manual and they were completely off. I have a new (2nd hand) ignitor on the way but I want to be sure that I don't fry this one. As far as I can tell I should be running the following to the ignitor:
- brown: 12V from battery +ve through the ignition
- black/yellow: ground
- grey: ~7V from the ignition
- green/black: ?
- green and black: to the coils

I will be replacing the ignition and need a resistor on the grey wire to drop the voltage. Does anyone know what I can use? Seems the ignition I have isn't working properly otherwise I would try pulling it apart and nicking the resistor...
There are some diagrams below. As far as I can tell the green/black has to be connected to ground for the starter to work in the original setup. Does that mean it's the positive side of the relay switch circuit? Should I just not connect anything to it?

At this point I also have nothing against replacing the ignitor with an aftermarket one. Any good options?

The infamous grey wire plagues the ZRX community, too. The first response is to turn the ignition switch on and off several times in a row to clean the internal contacts. The "final solution" is to disconnect the wire from the ignition switch, and connect it to a switched 12v source via a resistor. ort do what Bruce outlines below.

. I have plagiarized the following from the ZRXOA--

I figured out why my ZRX will crank forever but not start once in a blue moon!I have been thinking about it due to a few responses I posted in bikes not starting threads so I decided to figure it out. Armed with the wiring diagram and the new ignition switch I bought 4 years ago I proceeded to investigate. The first thing that caught my eye was the grey wire from the ignitor to the ignition switch with no other connection point along the way. And there didn't appear to be a connection for it at the ignition switch either, an unused wire as it were. Pulled out the meter and started checking the grey wire to all the other wires with the switch off and then on. While in the on position I get 101 ohms to the brown and white wires so I pull the cover off and discover a resistor that's not shown on the diagram. Must be an anti-theft measure. The actual problem goes like this: this circuit is very low or essentially no current as it's just a signal to the ignitor. The switch contacts are most likely silver - cadmium which is used for high current switching. This type of contact needs a minimum of 10 ma current to clean itself or an insulating oxide forms on it, not a problem for all the other contacts as they switch at least a few amps. But the contact for the grey wire oxidizes due to insufficient "cleaning" current causing the no fire condition. Rapidly twisting the switch cleans the contact due to wiping action restoring the circuit and the bike fires off. The new switch in fact exhibited this issue the first time few times I turned it on giving a higher reading before settling down. In my controls career we used relays and switches with gold or gold flashed contacts for these low current signal applications.There is nothing to do unless the ignition switch fails for another reason. If your Rex cranks but doesn't fire twist the key rapidly several times, or permanently hook the grey wire to the brown\white wire through a 100 ohm 1/4 or 1/2 watt 2% resistor right at the ignitor. Then cut out the resistor in the ignition switch or don't hook up the grey wire going to the ignition switch when you wire in the resistor at the ignitor, you only want 1 resistor in the circuit.I have included the corrected wiring diagram portion. 

By the way, what do you hope to gain by ditching the stock ignition system?

wrote:

By the way, what do you hope to gain by ditching the stock ignition system?

Thanks for the info, I'll pull the ignition apart and check the contacts. 
I don't really want to gain anything with a different ignition, I just figured if I have to replace the ignitor and the ignition switch is getting replaced (due to size) I might as well broaden the search. I wasn't planning on changing the coils or pickups, but if there was another model with a compatible ignitor and no grey wire...

Now I just need to find out where the grey wire goes on the ignitor end and whether I need to do anything with the green/black one.

The factory system is pretty bullet proof. A few ZRX folk have had trouble with the security system (grey wire), but most do not. My ZRX is 21 years old and starts on the button every time.

If the ZR750 is the same, and it appears to be, the igniter must have that tiny voltage from the grey wire to come on. If you need to change the ignition switch, then the grey wire needs to be connected to a switched 12v wire via a resistor. It is easy, and probably much less hassle than trying to wire in some other igniter.

P.S. I hope you have the fsm for your Zephyr. Removing the ignition switch is more complicated than on KZs.

The green/black wire on the igniter is a safety interlock.  The first diagram does not show the green/black affecting the starter.  It shows that under certain conditions, the igniter will not function.  Grounding the green black wire of the igniter will bypass the safety systems and allow the igniter to work. 

The starter system has it's own connections to those interlock switches, probably through a relay in that "junction box" shown in the second diagram.  It appears you can bypass the starter safety system by connecting the yellow/red wire to the black/red wire.  Those two wires are seen at the "junction box".   

Thanks guys.
@TexasKZ: I have the manual (FSM and Haynes). We're pretty far along (it's my sons bike), we drilled the switch out sometime last year.

@loudhvx: you're right, thanks. I originally thought this but then somehow combined the two diagrams in my head. But if it was part of a relay switch for the starter then there would be a coil in the first diagramm. 

The first diagram omits the starter-related items.  Notice the starter wires are not even included.  There could be a relay in the junction box, but it won't be shown in the first diagram because it's not strictly ignition-related (which is the purpose of the first diagram).  The second diagram only shows it as a box.

The coil of the relay would be fed 12v by the black/red wire.  The ground of the coil would be established through the various safety switches.  The contacts of the relay would also be fed by the black/red wire.  The contacts would then feed 12v to the yellow/red wire to energize the starter relay.

It could be done other ways too, including transistors or other solid state devices.  Since it's drawn as a simple box, one would have to open it, or perform other tests, to know what's inside.

 

Got an email from gazzz with the last piece of the puzzle today. Once I knew where the wires were supposed to go all I had to do was wire it up and she fired up no worries 
I guess the grey wire had 12V on all the previous tests as I had it connected to the wrong terminal and the circuit wasn't closed. It does still seem strange that the ignitor failed almost all the resistance tests. I guess I need to check my multimeter 

Anyway, for anyone that "accidently" removes the grey wire, here's a photo from gazzz of the ignitor(igniter?) connectors (connecters?):

 

 

@loudhvx: I have a junction box lying around. Next time I get bored I'll pull it apart, though I imagine it's exactly as you said.

Glad to hear it started up!

I never gave much credence to resistance tests on things like igniters.  Resistance test results on non-linear semiconductors require the meters to be exactly the same as the original test meter, which is unrealistic considering how many different ways you can design a meter.  It also requires the manufacturer never changes the igniter design, which is also unrealistic.  Small electronic devices can be made many different ways to perform the same task, so a subcontractor can easily change a design to improve operation or save money.

Resistance checks are really only good for things that act like resistors.  Most electronic components don't really act like resistors, though you can still get a resistance reading for a specific type meter.