Another name for an M unit

[AllanB]

Trying to find some information on the wiring distribution unit on my 1983 Honda Shadow NV400 (similar to the VR500), I think the modern equivelent is an M-Unit but when I google it, it comes up with nothing. The one on the bike is a bit worse for wear in terms of I.D.ing the I/Os labeling, so a drawing would be helpful as the wiring isn't 100%.

 

The layout is not the same as the modern M-Units (I have seen on Youtube) and wonder if the old Jap ones, or just old Hondas were standardised... yes any info at all.

 

Would anyone suggest removing it, or direct wiring some of the items? The rev limiting lamp comes on for no good reason and wonder if it was connected to anything, or was just a warning light, maybe there are some other electric issues too.

 

I have repaired/replaced all the damaged/bodged/corroded wiring, so just this unit is left.

 

[OneMoreFarang]

I have no idea about any M-Unit but many years ago, 1983 sounds about right, I worked successfully on the cabling on a couple of small bikes and cars.

If you explain what the problem is and maybe attach a picture or two, maybe I or others can give you some input.

 

[canthai55]

M unit - do you mean fuse box ?

Or the main wiring harness distribution point - where 12V is sent to the various circuits ?

[thaiguzzi]

You've seen something made by a German high end company called MotoGadget. They specialize in high end high quality electronics and electrical components for custom motorcycles only. Their items are not cheap, but of the highest quality. The M Unit you are looking at starts at around 200$ and is basically a high end fuse and distributor board/box rolled into one which simplifies (muchly) the wiring to and from the switch gear and the various components. It would be a waste of money unless all your switchgear was also of the highest (read new) quality, not 35 + y/o stock Japanese.

It is, like all their stuff, a very nice bit of kit.

I would guestimate you recquire something like Canthai posted above. 10$ rather than 200.

TBH, on a 35 odd y/o bike, especially an '83 Jap bike, it would be more sensible to rip the whole harness out and start with fresh wire and new connectors.

And mebbe a new 200$ M Unit.........

Edit.

By the way,

how's the Honda 400 Shadow cafe racer project coming along?

We are all looking fwd to your custom creation when it's finished.

[canthai55]

In 35 years wire manufacturing has made great strides. Much better quality.

Me - I would carefully remove ALL the wiring, lay it out flat, get some new wire the same color and gauge, and as Guzzi said above replace everything. New ATO fuse box.

Corrosion can creep into the insulation by terminals and corrode. You will never see any sign of it. And spend countless hours chasing a ghost.

 

[OneMoreFarang]

2 hours ago, canthai55 said:

In 35 years wire manufacturing has made great strides. Much better quality.

Me - I would carefully remove ALL the wiring, lay it out flat, get some new wire the same color and gauge, and as Guzzi said above replace everything. New ATO fuse box.

Corrosion can creep into the insulation by terminals and corrode. You will never see any sign of it. And spend countless hours chasing a ghost.

If you want to make it perfect then new wiring is obviously a good idea. But it's a lot of work to do this and even more work if you want to do it real accurate with new connectors.

Personally I think 35 year old wire does not have to be bad. Check it and replace what is necessary but I would think twice doing it all new.

 

[canthai55]

Hey Guzzi ... bit off topic, but pertains to wiring.

Bought the coach pictured below, stripped the interior and heating system, all new 120V interior wiring, propane stove, small diesel fired boiler to keep coach warm and could preheat engine during the winter before startup

Every wire in that coach was white. Marked only by a small aluminum ring crimped at each end with a circuit number on it.

So the NV wiring would be easy !!!

 

[thaiguzzi]

7 hours ago, canthai55 said:

Hey Guzzi ... bit off topic, but pertains to wiring.

Bought the coach pictured below, stripped the interior and heating system, all new 120V interior wiring, propane stove, small diesel fired boiler to keep coach warm and could preheat engine during the winter before startup

Every wire in that coach was white. Marked only by a small aluminum ring crimped at each end with a circuit number on it.

So the NV wiring would be easy !!!

 

Off topic - nice bus!

All alloy coachwork. Sweet!

I can see some Fabulous Furry Freak Brothers stories coming up soon..............

I have some bus/coach stories from the hippy/biker mid 80's to tell.

Not fit for this publication though..........

[canthai55]

Ass, Grass, or Gas - no one rides Free

555

[AllanB]

On 11/25/2018 at 1:39 PM, thaiguzzi said:

You've seen something made by a German high end company called MotoGadget. They specialize in high end high quality electronics and electrical components for custom motorcycles only. Their items are not cheap, but of the highest quality. The M Unit you are looking at starts at around 200$ and is basically a high end fuse and distributor board/box rolled into one which simplifies (muchly) the wiring to and from the switch gear and the various components. It would be a waste of money unless all your switchgear was also of the highest (read new) quality, not 35 + y/o stock Japanese.

It is, like all their stuff, a very nice bit of kit.

I would guestimate you recquire something like Canthai posted above. 10$ rather than 200.

TBH, on a 35 odd y/o bike, especially an '83 Jap bike, it would be more sensible to rip the whole harness out and start with fresh wire and new connectors.

And mebbe a new 200$ M Unit.........

Edit.

By the way,

how's the Honda 400 Shadow cafe racer project coming along?

We are all looking fwd to your custom creation when it's finished.

The ones I have seen on Youtube don't have fuses in them, just inputs and outputs and apears to be similar to what is fitted to my bike, the 400 Shadow from new.

 

I am just making a start on the bike, having just got airconditioning fitted in my shed and very nice too.

 

I have had 2 different exhaust baffles made and the idea is to get it running make it look better and then strip and paint. It won't be that exciting, just trying to change the appearance and make it more comfortable as a cruiser.

 

It has always had the right amount of power/torque for us, smooth engine/gearbox with overdrive, shaft drive and is easy to ride at any speed.

 

I may post some pictures if it don't look too crap.

I am also trying to get hold of some stretch seat fabric as I have a few ideas of how to stop it "bustin' my ass".

[thaiguzzi]

9 hours ago, AllanB said:

The ones I have seen on Youtube don't have fuses in them, just inputs and outputs and apears to be similar to what is fitted to my bike, the 400 Shadow from new.

 

I am just making a start on the bike, having just got airconditioning fitted in my shed and very nice too.

 

I have had 2 different exhaust baffles made and the idea is to get it running make it look better and then strip and paint. It won't be that exciting, just trying to change the appearance and make it more comfortable as a cruiser.

 

It has always had the right amount of power/torque for us, smooth engine/gearbox with overdrive, shaft drive and is easy to ride at any speed.

 

I may post some pictures if it don't look too crap.

I am also trying to get hold of some stretch seat fabric as I have a few ideas of how to stop it "bustin' my ass".

No.

They have fuses but not as we know it.

Resettable trips if you like.

Also, all the relays are in there, inc indicators with adjustable flash signals and times.

And a fault finder map circuit.

Everything is state of the art electronic.

There is nothing like it on the market, nor any of their other products (check their switchgear out !!), hence they can charge a premium.

Also there is not a stock production bike made, or ever been made with anything remotely as clever nor as sophisticated, nor similar as the M Unit.

 

Good luck with your project.

 

[AllanB]

43 minutes ago, thaiguzzi said:

No.

They have fuses but not as we know it.

Resettable trips if you like.

Also, all the relays are in there, inc indicators with adjustable flash signals and times.

And a fault finder map circuit.

Everything is state of the art electronic.

There is nothing like it on the market, nor any of their other products (check their switchgear out !!), hence they can charge a premium.

Also there is not a stock production bike made, or ever been made with anything remotely as clever nor as sophisticated, nor similar as the M Unit.

 

Good luck with your project.

 

Okay, not the same then, this is quite small, probably a wiring distribution point as suggested by CanThai55.

 

Rewiring the bike, bypassing this device is gonna take some time, maybe when I strip and paint the bike. Can you buy small quanities of wire in order to keep colour coding the same, or are their kits for this?

 

Haven't managed to find an accurate wiring diagram for the Jap home market bike. So will have to make one....

[OneMoreFarang]

11 minutes ago, AllanB said:

Can you buy small quanities of wire in order to keep colour coding the same, or are their kits for this?

Obviously you can buy standard wire in many places.

I think I saw on this website also wires with multiple colors like grey-blue or something like that.

But I have to admit I don't see them in the moment. Maybe have a look here:

https://www.pololu.com/category/39/cables-and-wire

[AllanB]

This is the unit in question and it doesn't look in great condition.

[AllanB]

7 minutes ago, AllanB said:

This is the unit in question and it doesn't look in great condition.

Eliminating would remove a large number of push on connectors. Maybe Honda thought it would be a good idea at the time?

 

 

[canthai55]

https://www.painlessperformance.com/

I have used these kits many times. All wire of the highest quality, each one marked aprox every 2 feet with circuit number on it.

As I said above, if you want to do it right - and do it once - then do it with new wire.

Use terminal blocks as junction points, as many as you need, and wherever you can fit them. With ring terminals and non corrosive connectors with built in shrink tube. Push on style are used in assembly because it is quick, not because it is the best.

Main batt feed - with inline fuse - to under the seat. From there direct any power required to switches.

Do not use the bike frame as a ground - just asking for trouble.

All our trucks, dozers, excavators are computer controlled. Well over 90% of electrical problems are traced back to bad ground.