1980 Yamaha XS 400 Café Racer // M-Unit Basic Conversion Wiring Diagram

[KylesCafe]

Hey guys,

I'm pretty new to this forum and this is my first resto project on a 1980 XS 400. I am ecstatic to find this collaborative site and thought I'd pick your brains regarding the wiring I'm planning to do on my bike. I see that there are other threads with the M-unit blue, but I'm planning to use the Basic module and keep my electric start, unlike a lot of other Cafés. Don't worry though, I'm planning to hide it all under my seat by using a Antigravity 8-Cell battery, which I think has enough amps to crank over. I found a universal wiring diagram published by Revival motorcycles, but I do see some nuances when it comes to my make and model. I'm just a 21 year old guy trying to learn how an engine works and learn something new. Wiring is definitely not my strong suit by any means. I did manage to design the following diagram with images of components that exactly if not closely resembles my setup. If I could have people who feel this is their expertise look it over and give me any feedback or suggestions on my schematic, that would be amazing and help me get back on the road quicker. Any help would be greatly appreciated. I'll also attach some before and afters for you guys to check out!

Thanks in advance,
Kyle

https://en.wikipedia.org/wiki/Café_racer

 

[KylesCafe]

Hey guys,

I'm pretty new to this forum and this is my first resto project on a 1980 XS 400. I am ecstatic to find this collaborative site and thought I'd pick your brains regarding the wiring I'm planning to do on my bike. I see that there are other threads with the M-unit blue, but I'm planning to use the Basic module and keep my electric start, unlike a lot of other Cafés. Don't worry though, I'm planning to hide it all under my seat by using a Antigravity 8-Cell battery, which I think has enough amps to crank over. I found a universal wiring diagram published by Revival motorcycles, but I do see some nuances when it comes to my make and model. I'm just a 21 year old guy trying to learn how an engine works and learn something new. Wiring is definitely not my strong suit by any means. I did manage to design the following diagram with images of components that exactly if not closely resembles my setup. If I could have people who feel this is their expertise look it over and give me any feedback or suggestions on my schematic, that would be amazing and help me get back on the road quicker. Any help would be greatly appreciated. I'll also attach some before and afters for you guys to check out!

Thanks in advance,
Kyle

View attachment 35589

 

[amc49]

Does one of those units have separate fuses for all the power runs? Wondering as any electrical issues there pop one fuse only with no direction of which way to look for trouble, more than one fuse helps that a lot. Unless the box itself has diagnostics built into it. Beyond that wondering why people use them, you can wire a bike easily not having them at all.

Where are any instrument lights? In some states you must have a bright indicator for headlight or safety inspection fails.

Have fun.

EDIT: my M-unit questions answered by the link in post #5 below. OP may not need a starter solenoid either, the M-unit claims to do that.

 

[Reverend]

Hi guys! I'm new to the forum and wanting to take an old xs400 in my barn and make a bad-ass cafe racer out of it for a friend.

My first thought is that I need this to be a reliable bike, which means all new electrics.

Can someone explain what an "m-unit" is? Does it get rid of the coils and all the other '70s tech on the electrical side?

Thanks!

 

[amc49]

Nice thread jack there.

It is considered tacky to jack somebody else's thread up to take it over.

You should create a brand new post.

Now if I or anyone else replied here, they (and you) don't know if it's to you or the other guy, exactly what we need now in this country. More confusion to mess things up.

Not to even mention that the simple last question posed would be far better answered by simply doing a check on the main website for M-unit. Anf, no it does not dump the '70s tech like coils, you still need them. The unit is simply a control overlay when you pretty much already likely have one, just not as fancy.

I've personally created rock solid dead reliable bikes using the same old electrics that have sat for many years, or most of them anyway. M-unit is a waste of money to me, don't need them at all. But then I do the exact same to electronic cars with 5 miles of wiring in them.

https://motogadget.com/shop/en/m-unit-basic.html

 

[Reverend]

Well, I certainly didn’t intend to Jack someone’s topic, or cause confusion. Just trying to learn something good. My apologies to the OP.

I looked at the m-unit website and then asked my question here, which I thought was Germaine to the topic.

I’ll be more careful in the future.

 

[motoTrooper]

Hey Reverend, your post was perfectly relevant to the thread, amc49 needs to calm down as our avatars clearly display who we are and preclude confusion.

 

[Reverend]

Thanks, motoTrooper. I don't aim to start a war right out of the gate!

I'm just starting my build (my first) and don't know a lot yet. I've got some basic skills and tools, and really want to make sure this bike is reliable for my friend before I hand it over... I've struggled in the past with crappy wiring, and the wiring on this bike is just ragged all to hell and gone, so I'm thinking new loom at least, and then I came across this thread and wanted to learn more. I'll be following and not commenting from here on out.
Thanks

 

[xschris]

Asking questions is what this place is all about. Some have answers, but none have all the answers. Being able to keep learning is what makes us better at this. I have had these bikes(xs400) for 21 years now and put almost 40k miles on them. I still have lots to learn. Start a build thread of your bike so we can see and maybe help you.

 

[Reverend]

Asking questions is what this place is all about. Some have answers, but none have all the answers. Being able to keep learning is what makes us better at this. I have had these bikes(xs400) for 21 years now and put almost 40k miles on them. I still have lots to learn. Start a build thread of your bike so we can see and maybe help you.

Thanks!!! I really love this little bike. I've been wanting to get stuck in on a build for a long time, so I'm def planning on having fun!

 

[amc49]

'Start a build thread of your bike so we can see and maybe help you.'

Somebody who understands web etiquette and how to stop utter confusion. Diplomatic about it as well.

Reverend you're fine, I just come across as abrasive sometimes, it comes from a lifetime of getting things done instead of screwing around.

I would not buy a new harness if you M-unit, the part forces you to relocate lots of terminations meaning tearing that new harness pretty much up, the latter is laid out to augment the OEM method of controlling everything. When you M-unit you are pretty much building a new one-off harness yourself.

 

[Reverend]

Thank

'Start a build thread of your bike so we can see and maybe help you.'

Somebody who understands web etiquette and how to stop utter confusion. Diplomatic about it as well.

Reverend you're fine, I just come across as abrasive sometimes, it comes from a lifetime of getting things done instead of screwing around.

I would not buy a new harness if you M-unit, the part forces you to relocate lots of terminations meaning tearing that new harness pretty much up, the latter is laid out to augment the OEM method of controlling everything. When you M-unit you are pretty much building a new one-off harness yourself.

Thanks, AMC. I appreciate it. I can be obtuse, so I get it. Thanks for the info on the m-unit. I'm psyched to get started... took a long hard look at the bike today and have begun the design stage. First build. Excited.

 

[cezzz]

Hey guys,

I'm pretty new to this forum and this is my first resto project on a 1980 XS 400. I am ecstatic to find this collaborative site and thought I'd pick your brains regarding the wiring I'm planning to do on my bike. I see that there are other threads with the M-unit blue, but I'm planning to use the Basic module and keep my electric start, unlike a lot of other Cafés. Don't worry though, I'm planning to hide it all under my seat by using a Antigravity 8-Cell battery, which I think has enough amps to crank over. I found a universal wiring diagram published by Revival motorcycles, but I do see some nuances when it comes to my make and model. I'm just a 21 year old guy trying to learn how an engine works and learn something new. Wiring is definitely not my strong suit by any means. I did manage to design the following diagram with images of components that exactly if not closely resembles my setup. If I could have people who feel this is their expertise look it over and give me any feedback or suggestions on my schematic, that would be amazing and help me get back on the road quicker. Any help would be greatly appreciated. I'll also attach some before and afters for you guys to check out!

Thanks in advance,
Kyle

View attachment 35589

Hey Kyle, curious if everything workout with that wiring diagram? If any issues occurred that required changes?

 

[Qwervo]

I’m also interested @KylesCafe . Did your diagram work? It looks pretty solid. I’m also trying to follow Revival’s diagram, but their Starter solenoid have 6 wires compared to mine having 4 only. Would appreciate some advice and learnings from your build.