Mini-Build: Rewiring with Motogadget m-Unit, m-lock, Motoscope tiny, etc

[Myke Nytemare]

Hello all,

This site has been a great help over the last year of having my 77 XS400D. Recently, it seems the butchered wiring harness has caused the bike to not start, not have lights, have the horn constantly beep, etc. I have some skills (I used to paint cars and I do my own gunsmithing and home construction-type stuff), just not a big electric background, so I will definitely ask questions while this project is going on.

A friend gave me a Motogadget m-Unit, so I decided I would go all out and drop some big cash to remove the factory gauges/ignition switch and replace them with motogadget products as well. I just purchased the m-Unit wiring kit (hopefully minimize the amount of wire I need to purchase mid-build), the m-Lock, the tiny gauge and an assortment of bullet connecters and a few multi-pin molex connectors.

I won't be using the electric start but plan to keep the factory handlebar controls, along with turn signals to be street legal. I likely will remove the neutral safety and kickstand switch as well).

Any input would be greatly appreciated as I start this project. I will post pics as I complete the tear down over the next few weeks in preparation for the first 2 weeks of April, when I have some off days from work and hope to get the harness layout and crimping almost complete.

 

[Jeff0133]

Wow!...a friend GAVE you a M-Unit? ....wish I had rich friends too
Not assuming anything here...but you do know that the neutral and kickstand safety switches are just THAT....safety....not being a dick here just wouldn't want you to lay down your newly rebuilt bike or get hurt just for the sake of a few grams less...
I know from personal experience from a bike that didn'the want to start...realising that it was'not in neutral had it started....it would have hit the back wall of the shop...and God knows what else. But then again not everybody is as A.D.D. ....

 

[Myke Nytemare]

He gave me the m-unit from his totaled bike and he is not going to ride for a while....so no rich friends here. We did test it to make sure it powers off and works. I will likely just wire in the "safeties" or at least the neutral switch into the same wire as the run switch as it won't really add bulk to the harness.

I'll post some parts pics and preliminary wire layout stuff over the next week.

 

[Myke Nytemare]

Not quite major progress, but I have the old harness, gauges, headlight, front signals, starter, and solenoid removed. I believe I will make a layout board like @drewpy did in the next week as I start laying out the wires. Likely going to buy an m-button to eliminate a handful of wires running back to the m-unit and simplify my harness a little more. Hope to get the starter clutch/sprocket out later this week.

I'm still not 100% sure what the little box I circled in the first pic is (the flasher relay is the silver cylinder, right?)...or how I will wire up the old regulator and rectifier to work with the m-unit/kick only, but I have time to figure that out in the upcoming weeks.

 

[xschris]

That's the flasher auto canceling relay.

 

[drewpy]

using a layout board is def the way to go. just work the wires to each area and you can't go wrong

 

[Myke Nytemare]

I plan to start later this week...

...will definitely call on you and others to let me know what I need to keep and how to hook-up the regulator/rectifier/stator/coils in order to work with the m-UNIT!

 

[Myke Nytemare]

Before I actually start cutting wires for my board, I am having trouble figuring out which wires on the factory left/right handlebar switches I will need to use going forward.

The wiring diagram I have is a little blurry and if anyone has any clearer scans (77 XS400-D) it would be a great help...otherwise, I guess I am going to power the wires and use a tester/multimeter to figure out what is going on.

 

[BBS360]

Pretty decent diagrams in the Haynes manual:
http://www.xs400.com/threads/re-run-free-full-yamaha-service-manual.14495/#post-151524

 

[Myke Nytemare]

Pretty decent diagrams in the Haynes manual:
http://www.xs400.com/threads/re-run-free-full-yamaha-service-manual.14495/#post-151524

Thanks...easier to read the letters/color codes. Now to get that all sorted out in my head and on paper!

 

[Myke Nytemare]

Got the new turn signals wired into the bars....

 

[Myke Nytemare]

Just finished a little wiring and drilling/tapping a hole to mount the grounding block for the layout under the seat. Wiring board and harness build in the next few days

 

[Myke Nytemare]

NEED SOME INPUT!!!!

As I finally start the wiring layout, I really need input on what wires from the alternator/regulator/rectifier/coils I need to keep and connect (either to each other or to the battery) to have the system work properly.

The only feed from the m-unit itself is a constant hot to the coils AND I am NOT using an electric start and have the m-lock as an ignition switch. Any help would be much appreciated @drewpy @BBS360 @Wolfe_11B

 

[drewpy]

you'll need all the wires from stator, RR etc. there's only 1 redundant one that would be the 4th white wire to the relay for the headlamp (UK models don't have always on lamps)
if you use modern wires, they are smaller diameter than the old originals

 

[Myke Nytemare]

I guess I'm curious how to connect them as the original wiring diagram is very confusing. Just looking to figure out which wires should go to the m-unit (I think the two positives from the coils), and how I should connect the stator wires and the reg/rec to the coils.

 

[drewpy]

the stator and RR don't connect to the coils, they are only for charging the battery

 

[BBS360]

Stock reg & rec?
Looks like you can power the coils and regulator off the Aux output.
The red from the rectifier would connect between the main fuse and the m-unit. Where the generic example in the m-unit instructions show the regulator connecting.

The m-unit instructions have pretty good examples for everything else.

 

[Myke Nytemare]

Yes, stock reg & rec. Thanks @BBS360 and @drewpy I wanted to have some experienced/guru input along with the stock yamaha wiring diagram and the m-unit diagram to make sure I don't cross any wires!!!

Let me "draw up" a diagram and share before I finalize that layout. I am about 50% through the main harness (lights and grounds) at the moment and once everything powers up and works, I will do the stator/reg/rec etc before taping the whole harness up.

THANKS A MILLION....SERIOUSLY!

 

[Myke Nytemare]

Just realized the Yamaha wiring diagram shows the coils/condenser as having gray and orange wires. My coils have red/white and orange wires and the condenser just black wires.

 

[BBS360]

As long as the left contact breaker goes to the left coil, and right to right, I believe you'll be ok.
Condenser shouldn't matter left/right cylinder.
The 12V supply to the coils doesn't matter left/right.