Relay for CDI to M Unit.

[Guest]

So I have an m unit on my 1980 gs750 and my bike doesn’t have spark. So I read up that there needs to be a relay in between the CDI to the M Unit. I included the revive wiring diagram that shows how to do that, but my CDI only has 2 wires excluding the ones to the stator which is the green and blue wire that goes into the signal generator. In the diagram there’s a 3rd one going from the CDI to the relay. And the description says find the kill button? Can someone explain the diagram as to where that 3rd wire came from and where am I suppose to connect it too. Thanks in advance.

not able to upload photo for some reason but the diagram is in the link: https://technicalarticles.revivalcy...ow-to-Integrate-a-CDI-Ignition-with-an-m-Unit

 

[Killer2600]

The info found at that link in incorrect for suzuki gs'es. Further I'd like to clarify, what you call CDI is called an ignitor, and what you call a stator is called a signal generator or pickup coil. The GS'es aren't equipped with Capacitive Discharge Ignitions.

 

[tom203]

I?d look at this wiring diagram ....your 750 is real similar. Note the wires leading from signal generator up to ignitor....from there it?s off to ignition coils.
has this thing run for you yet??

http://members.dslextreme.com/users/bikecliff/images/80GS850GT_wiring_color-new.png

 

[pdqford]

but my CDI only has 2 wires excluding the ones to the stator which is the green and blue wire that goes into the signal generator.

Be patient with me here, but the unit you refer to as a CDI, is probably your “ignitor”, and has a green wire and a blue wire that go to the signal generator. But there shouldn’t be any wires going from your ignitor to the stator. Wires from the stator go to the regulator/rectifier. Don’t think you have the R/R and ignitor mixed up?

Where is what you call your “CDI” located?

 

[Guest]

Sorry, this is my first bike . Trying to do my own research but people are calling it that I figured they were right. But thanks for the lesson.

 

[Guest]

Oh yeah sorry I didn?t mean from the igniter to the stator, it?s connected to the coils.

 

[Guest]

So igniter is connected to the pick up(blue, green). And then the other wires to the coils. I didn?t have a OEM wiring harness when I got the bike, it was a ball of wires missing a bunch of them so I basically had to re-wire everything and bought the m unit.

 

[pdqford]

Oh,okay.

The yellow wire at the ignitor comes from the kill switch.
When the ignition switch is on and the kill switch is in the run position the yellow wire coming from the kill switch provides power to the ignitor by way of that yellow wire, and also provides power to both coils.

One of the black wires at the ignitor provides a ground for the ignitor.

The other black wire at the ignitor provides a ground to one coil to cause that coil to fire when the ignitor pulls it to ground.

The white wire at the ignitor provides a ground to the other coil to cause it to fire when the ignitor pulls it to ground.

So how do you have the “M” unit wired in to the ignition circuit?

 

[Guest]

I have the ignitor and the coils wired the way you said. But I don?t have the kill switch because I?m using a momentary button for the on and the off, which is why I thought I needed a relay unless I get a separate button just for the kill switch. Could it be a weak ground? Bad ground on ignitor or bad ground on the coils? The black wire from the coil is connected to the B/Y of the ignitor.

 

[pdqford]

Are you using the start button to start the engine?
And double pushing the start button to shut the engine down?

 

[pdqford]

Following from the M unit’s ignition output terminal, where That wire connect to?

And how are you toggling the M unit to get it to power up its ignition output terminal?

 

[Guest]

Are you using the start button to start the engine?
And double pushing the start button to shut the engine down?

yeah that was my plan, I still have to configure the m unit. Or would having a separate button as a kill switch be better?

 

[Guest]

Following from the M unit’s ignition output terminal, where That wire connect to?

And how are you toggling the M unit to get it to power up its ignition output terminal?

i have the ignition wired to the B/W wire of the ignitor.

 

[Guest]

Is 300ohms resistance on the pickup bad? The owners manual says 130-200, anything under 130 is bad, but is being over at 300 bad?

 

[pdqford]

i have the ignition wired to the B/W wire of the ignitor.

So you have the ignition output terminal of the M unit going to the B/W of the ignitor?
That B/W wire is the GROUND for the ignitor!
(Maybe someone smarter than me can tell you if that would cook your ignitor?)

How are you telling the M unit to turn on its ignition output?
Has it ever sent power to the B/W wire of the ignitor?

If the M unit’s ignition output terminal is connected to that B/W wire to the ignitor, How are you powering your ignition coils?

 

[Guest]

Oh crap sorry I meant the B/Y wire. I double checked the color wire diagram and just realized I said the wrong color. So it?s basically the 2 yellow that goes into the kill switch, the B/W is the ground and the B/Y is to the black of the ignitor. I would probably need the kill switch huh? This might be a dumb question, but if I have a kill switch also a momentary button, wouldnt it never be on unless I hit the button? Cause the stock handlebar switch is off/on right? I bought a used pick up for cheap that just came home, I?ll install that and let you know how it goes. I?m about done to call it quits with this bike haha. Went from 0 knowledge to pretty close to decent in 2 months. Took apart everything cause I had no choice. Just not the main motors components.

 

[Rijko]

yeah that was my plan, I still have to configure the m unit. Or would having a separate button as a kill switch be better?

You need to check the M-unit programming - is it in pushbutton mode or conventional switch mode.
That's why i advised you to check the control lights on the m-unit so you can verify functionality.

 

[chris]

Hi, with m-unit it is much simpler and easier to just use 5 momentary push buttons. No relay or kill switch is needed, just hit the start button twice to kill the engine. If you are going to the trouble of changing all the wire and installing a m-unit, it makes no sense to reuse old switches or anything. Remember all inputs are just dry contacts to ground with the exception of ignition which is + 12 v to igniter. I think you might be over thinking this.

 

[Rijko]

Hi, with m-unit it is much simpler and easier to just use 5 momentary push buttons. No relay or kill switch is needed, just hit the start button twice to kill the engine. If you are going to the trouble of changing all the wire and installing a m-unit, it makes no sense to reuse old switches or anything.

I did - just because i wanted to keep the conventional/classic looks ...