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M-UNIT BLUE

Tink

Tink

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Has anyone fitted an M-unit to their CB750. I inherited a real mess of a wiring system when I bought a project bike (1982 CB750) from a kid that ran out of steam/skill when building a café racer. I'm left with just the electricals to sort out - but a lot of wiring has been replaced (using all the same color wire!) so it's a total nightmare.

I'm thinking it might be better to start with a clean sheet. I'm guessing coils, spark units and regulator/rectifier will still retain all their wiring though? Has anyone had any experience?

And, the manual I have only has black and white wiring diagram. Does anyone know where to find a color version? I've sifted through a lot on Google but couldn't find anything.
 

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Watching this thread with interest. I’m not too far off doing a complete rewire and thinking about the M-Unit. It’s quite expensive and Brick House Builds has an alternative cheaper version that might be worth a look.
 
I've wired a few custom bikes using an M-Unit, but frankly it complicates the wiring when trying to use stock components - especially bar switches. Unless you have to have some of the features and using momentary switches, I think it's much simpler to use a standard fuse box. A little fancier would be the fuse box systems offered by Eastern Beaver that employ a relay to power-up.

I do have a thread underway that shows some custom wiring https://www.cb750.com/threads/resto...-kinda-superbike-style.7970/page-2#post-39642

Stock reproduction wiring harnesses are available from www.CB750SUPPLY.com as cheaply as custom making your own harness from scratch - maybe cheaper.
 
Hmmm, OK, not a fan of the M-Unit. I'd ordered it already so it's after the proverbial horse has bolted. I'll check out the harnesses, thanks.
 
I installed a Mo Unit blue on my RC01 (KZ) 1979 last week. Cant recommend it enough. I still got it all in my head and some on paper so feel free to ask any questions. But yeah, the ignition and charging stays the same.
 
Thanks Nylundarn, good to know. I may take you up on that. I've watched several videos on the subject, some more helpful than others. I will try and make one myself to help others in future.

https://www.youtube.com/playlist?list=PLb-9jEv5hdG-SvnN7CUSeKJC6B4BaYz8r covers my previous CB750 build (a 1978) and the current one, a 1982. The newer model has spark units to add to the complication, which it seems are some sort of early ECU type deal :/
 
Tink said:
Thanks Nylundarn, good to know. I may take you up on that. I've watched several videos on the subject, some more helpful than others. I will try and make one myself to help others in future.

https://www.youtube.com/playlist?list=PLb-9jEv5hdG-SvnN7CUSeKJC6B4BaYz8r covers my previous CB750 build (a 1978) and the current one, a 1982. The newer model has spark units to add to the complication, which it seems are some sort of early ECU type deal :/
Click to expand...
Wow! Your 1978 looks fantastic. Its always hard to find a video tutorial that is accurate enough to implement on your own bike. I took copies of the wiring scheme of my Haynes manual and then marked where to cut the original wiring harness. Found it easiest to save all connectors for spark units/ignition and charging because thats 60% of what you need. Will you be relocating much of the components or keep them in the same place?
 
Thanks Nylundarn, appreciate it :)

Most of the "stuff" regulator/spark units etc. will be under the seat, I hope ... if there's room
 
Tink said:
Thanks Nylundarn, appreciate it :)

Most of the "stuff" regulator/spark units etc. will be under the seat, I hope ... if there's room
Click to expand...
Sounds good, I just about got everything to fit under my seat. But I also made it harder by choosing a very shallow electronics tray from Hookie Co. Thats where the M-unit really comes in handy, saves so much space.
 

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