Author Topic: CB550K M-Unit, M-Button, Kick Start Only Wiring  (Read 342 times)

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Offline vmantia1980

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CB550K M-Unit, M-Button, Kick Start Only Wiring
« on: June 01, 2020, 09:27:49 pm »
Hey guys,

I have done my due diligence and have come up with the following diagram for my 550K.

Main components:

1) M-Unit
2) M-Button

No Starter, kick start only!

Questions:

1) Can I run the Brake Light Switch for the rear brake to the M-Unit Brake Input even though I am using the M-Unit or leave it as the diagram and run the rear brake cable up into the M-Unit?
2) Should the Ricks go directly to the BAT terminal or tie in with the Battery and Key Switch?
3) Should M-Unit Earth Ground have to be separate from the Battery and Key/Ricks earth ground?

Any wiring tips or simplifying advice is welcome!

Thanks all!

Vinny
1977 Honda CB550K
Stripped, Chopped, Raw!

Offline theDQG

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Re: CB550K M-Unit, M-Button, Kick Start Only Wiring
« Reply #1 on: June 03, 2020, 02:26:34 pm »
Hey guys,

I have done my due diligence and have come up with the following diagram for my 550K.

Main components:

1) M-Unit
2) M-Button

No Starter, kick start only!

Questions:

1) Can I run the Brake Light Switch for the rear brake to the M-Unit Brake Input even though I am using the M-Unit or leave it as the diagram and run the rear brake cable up into the M-Unit?
2) Should the Ricks go directly to the BAT terminal or tie in with the Battery and Key Switch?
3) Should M-Unit Earth Ground have to be separate from the Battery and Key/Ricks earth ground?

Any wiring tips or simplifying advice is welcome!

Thanks all!

Vinny

1) Run BLS to brake input. You will need to do that so that brake output lights up.
2)  Ricks directly to battery and to M-unit (if that's what you mean). Run a smaller AWG wire from M-unit to key switch.
3)  Ground the M-unit to the frame. Use same AWG as cable you are using from battery to M-unit.

I see you are using the M-button; I should caution you that some people have reported "noise" interference with the M-button even  if you put it in the handlebars. Some of them have solved it by putting the M-button in a short length of 1/2" copper pipe and running the green wire through a wire mesh loom.

Addendum: The green wire is a LinBus wire that's unfortunately unshielded from electrical interference. Hopefully Motogadget will address this in a subsequent version. If you do use it, be careful to shield it well and route it so that it's on the side of the frame away from the coils.

I myself elected to skip the M-button and run five extra wires back to input. That's the tradeoff but less things go wrong.
« Last Edit: June 04, 2020, 03:28:56 am by theDQG »
'83 xv920
'76 xs650
cb750 k4 (2)
'81 R100RS

DQG = The Dumb Question Guy. I ask dumb questions all the time. Bike over ego.

Offline vmantia1980

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Re: CB550K M-Unit, M-Button, Kick Start Only Wiring
« Reply #2 on: June 04, 2020, 01:23:26 pm »
Thanks theDQG, I will give the M-Button a shot.  I see in my post I fouled up the Rear Brake description.  What I meant to say was, the front break is going to the M-Button.  Can the rear brake switch go directly to the Brake input on the M-Unit even though I will be using the M-Button or do I have to bring the rear brake switch positive lead all the way up to handle bars and splice into the front brake switch?

Does the rest of my wiring look on par?  Especially focusing on the Contact Breaker, Coils and Rick's?
1977 Honda CB550K
Stripped, Chopped, Raw!

Offline theDQG

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Re: CB550K M-Unit, M-Button, Kick Start Only Wiring
« Reply #3 on: June 05, 2020, 07:12:43 am »
Thanks theDQG, I will give the M-Button a shot.  I see in my post I fouled up the Rear Brake description.  What I meant to say was, the front break is going to the M-Button.  Can the rear brake switch go directly to the Brake input on the M-Unit even though I will be using the M-Button or do I have to bring the rear brake switch positive lead all the way up to handle bars and splice into the front brake switch?

Does the rest of my wiring look on par?  Especially focusing on the Contact Breaker, Coils and Rick's?

Yes, rear brake switch directly to brake input.

Your wiring diagram looks fine, although I am no expert on the 550.

I would skip the grounding terminal and find a place on the frame and ground everything to that point. Ground battery and M-unit to separate points on the frame using same AWG wire as the one supplying positive to each, and have another point for the rest of the ground wires to terminate at.  You want the frame as the "ground zero" to eliminate frying anything in case of incidental contact.

'83 xv920
'76 xs650
cb750 k4 (2)
'81 R100RS

DQG = The Dumb Question Guy. I ask dumb questions all the time. Bike over ego.