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81 gs450 munit simple wiring diagram?

  • Thread starter Thread starter Zella
  • Start date Start date
Z

Zella

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Ok my 81 gs450 had been slipping into a charging, starting nightmare. Can anyone firstly give me a wiring diagram for the munit and this bike? My other question is can I bypass the munit for the ignition. I would appreciate a simple wiring diagram for that. Any help would be so appreciated.
 
Might want to contact the maker of the "munit" (M-unit?) for a wiring diagram. Some of us have heard of such a device, very few have ever seen one, let alone played with one.

About the charging, verify you have a good stator, then install an SH775 R/R.

.
 
What is a "new tricks reg/rec"?

No matter how new your new R/R might be, I would still recommend an SH775.

.
 
The M-Unit is quite simple, but offers a lot of possibilities/choices.
There is a LOT of info to be found, Google is your friend.
It does take a little bit of effort to find out how it works and
which choices you want to make.
You do not offer much info, maybe it is installed on the bike
already ?

Several wiring diagrams, general info, and videos here :
M-Unit v2 : https://rbitter.home.xs4all.nl/M-Unit v2.html
M-Unit v3 : https://rbitter.home.xs4all.nl/M-Unit v3.html

Some of it is in Dutch but the wiring schemes and videos
should help you.

Yes, the M-Unit is easily bypassed, for ignition and starter.

So you need to know which model M-Unit : the first model
(black box) is produced in 2 versions, only slight differences.

The second model M-Unit ("blue") is completely reworked,
has more connectors and possibilities.
It has Bluetooth, smartphone app integration, etc.

A lot of the wiring depends on the use of the original
handlebar controls, or the push-button controls the M-Unit
is designed for.
 
I installed an m unit on my 81GS 450 with no real issues. As for wiring diagrams I used a combination of 3; the diagram that comes with the m unit, the original GS450 wiring diagram that came from this site I'm pretty sure, and a generic wiring diagram drawn on a whiteboard from the Revival Cycles youtube channel just to get my head around basic essentials of bike wiring for an m unit. I recommend this video its fantastic. Hang on I'll find it.....

https://youtu.be/-m5aUoAK_DM

This is how I've set up my starting and charging system. Being a bit of a flat-earther when it comes to electrical wiring I didn't deviate too much from the above unless I had to.

I didn't have any huge problems although there's some ongoing issues but nothing related to the m unit. The CDI has since crapped out and I'm in the process of installing a Boyer Bransden system but keeping the stock coils which work fine. Found a vacuum leak in the carbs too while it's been apart so it'll run even sweeter than before when it's back on the road.

Hope you get those gremlins sorted!
 
This is one of those times when there's just no good way to simplify the information further than the materials that come with the device.

It's a complex device, and every situation is different depending on what you have hooked up to it and where you're starting, whether you're keeping any stock wiring, etc.
 
I installed an m unit on my 81GS 450 with no real issues. As for wiring diagrams I used a combination of 3; the diagram that comes with the m unit, the original GS450 wiring diagram that came from this site I'm pretty sure, and a generic wiring diagram drawn on a whiteboard from the Revival Cycles youtube channel just to get my head around basic essentials of bike wiring for an m unit. I recommend this video its fantastic. Hang on I'll find it.....

https://youtu.be/-m5aUoAK_DM

This is how I've set up my starting and charging system. Being a bit of a flat-earther when it comes to electrical wiring I didn't deviate too much from the above unless I had to.

I didn't have any huge problems although there's some ongoing issues but nothing related to the m unit. The CDI has since crapped out and I'm in the process of installing a Boyer Bransden system but keeping the stock coils which work fine. Found a vacuum leak in the carbs too while it's been apart so it'll run even sweeter than before when it's back on the road.

Hope you get those gremlins sorted!

I have no experience with you bike, I did ask Boyer Bransden about a system for my bike Gs850gx and below is their reply i mention it in relation to needing their coils it may be worth checking before purchase.

Thank you for your enquiry, the GS 550 to 1000 micro power kit should fit, check the plate holding the triggers has two or three mounting screws, two is the our gs1a stator plate and three is our Kh1a plate.
The micro power kit comes with two modern miniature dual output ignition coils, the old coils are not suitable for any of our kits.
The advanver unit is taken to pieces and only the centre with the timing marks is used.
If the machine has an electronic tacho it will require recalibration.
Contact us at sales@boyerbransden.com they can quote you including delivery, and supply the extra wires you require to connect the stator plate.
 
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