TOPIC:

Hey all, after 42 years the wiring on my 79 C-2 is on it's way out. I decided to rewire it with an M unit, but I'm having a hard time wrapping my head around it. Has anyone here used the M unit before? My schematic leaves a couple of questions as well. Power to the coils, according the the schematic is Y/R. The Y/R wires are running into oblivion at the bottom of the schematic and to the starter switch. I've done some wiring before but I want to make sure I have this all planned out before I start the project. Any tips or anecdotes are greatly appreciated.

I started to hook up the M-Unit on my 83 GPZ-1100 and quickly realized it was going to be a complete rewire. Started by getting a copy of turbo cad and drawing out a wiring diagram. Been working on this part of my project bike off and on for 6 months.The wiring diagram is still in process and is changing as the wiring is installed on the bike. 
 

My m-unit blue has been on the bike for almost 4 years.

Your yellow/red will go to the ignition output(right side of the m-unit).

Your starter switch will be flipped to a ground wire instead of hot.
Turn signals, horn, brake, headlight, kill switches will all become ground switched.
This is nice as the switch wires can be 22awg or less running from the handlebars.

Your key switch remains +12v

 

That's a clean diagram. File size is a little small so I can't make out the details but it looks good.

So I take it in my diagram the extra yellow/red coming from the coils must have plugged into an accessory such as the siren or radio. If I'm understanding correctly all of my controls will be signalling the M unit by grounding out, and when they do they'll tell the output side to give power to the corresponding function. Will my indicator lights be tied into the output circuit for power? As for the ignition system, is it wired basically the same as stock for the points and coils? Am I running my head/tail light power from the ignition? Sorry for all the questions. I appreciate the help and patience. When I get this all figured out and tested I'll make up a nice diagram and upload it here for anyone in the future who might be doing the conversion.

  So I take it in my diagram the extra yellow/red coming from the coils must have plugged into an accessory such as the siren or radio.
Possibly, I didn't try to trace out where that wire went to.

If I'm understanding correctly all of my controls will be signalling the M unit by grounding out, and when they do they'll tell the output side to give power to the corresponding function.
Yep. Except for your key switch which is your LOCK input. That is still +12v, but it will be very low current draw. So that key switch wire could be small as well.

Will my indicator lights be tied into the output circuit for power?
There is a specific output for TURN R, TURN L, and BRAKE

As for the ignition system, is it wired basically the same as stock for the points and coils?
Yellow/Red wire goes to the IGNITION output on M-unit. Make sure it goes directly to the coils as stock goes through the kill switch.
Everything else on the ignition stays as is.

Am I running my head/tail light power from the ignition?
Low beam goes to LIGHT output
Hi Beam goes to HI BEAM output
Tail light can go to AUX 1 or AUX 2 output

Sorry for all the questions. I appreciate the help and patience. When I get this all figured out and tested I'll make up a nice diagram and upload it here for anyone in the future who might be doing the conversion.
No worries on the questions. It can mess with your head as it has a lot packed in that small box.

Oh, mount this box in a place where it won't get wet. MIne acts crazy when I spray water on it from washing the bike. It may be the water bridging the inputs and output.
When it dries off it's fine.

Stefan at Revival cycles goes through the M-unit as well

Agree with F64 the videos from Revival Cycles are most helpful.

Hope this attachment  is a little better.

I am in the middle of wiring the m-Unit into my bike and I started the wiring completely from scratch. It is a lot easier. all you need is the diagram from the dash so you know how to tie those in. run wire from M-Unit to switch, from switch to ground, from M-Unit to light or ignition or coil and the ground. it is so easy.

I think this will be more helpfull. technicalarticles.revivalcycles.com/hc/e...ersal-Wiring-Diagram