Author Topic: CB400F Motogadget m.unit thread  (Read 547 times)

Offline zombie365

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CB400F Motogadget m.unit thread
« on: March 21, 2021, 09:58:51 PM »
Hi all,

So currently planning my rebuild of the 400/4 I've scrapped the wiring loom and gone for the Motogadget m.unit blue.

Bike is going to be café racer style, hopefully not upset the purists to much! ;)

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

I'm after any tips or tricks when wiring this thing up and thought it would be useful to set up a dedicated thread, to help anybody else (and me) doing a similar thing to there 400/4. I design electronics for a living so not unfamiliar with this sort of stuff... although I've never done any major motorcycle wiring!

I am literally at the start, so to begin here's there "simplified" wiring diagram from moto gadget:

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Does anybody have a more defined wiring diagram for m.unit and 400f ?

I'm looking to use the original regulator/rectifier and an antigravity (or something similar) battery.

Any input greatly appreciated!  :)

Thanks
1977 Honda CB400F

Offline Bryanj

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Re: CB400F Motogadget m.unit thread
« Reply #1 on: March 21, 2021, 10:32:47 PM »
Ag battery will not like the origial reg rec set up as the charge settings are too coarse and top volts notaccurate enough

Online K2-K6

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Re: CB400F Motogadget m.unit thread
« Reply #2 on: March 21, 2021, 10:51:38 PM »
Has it any facility to monitor oil pressure switching and display?

Should be reasonably simple for usual function as there's not much to do on these bikes, two light filaments front and rear, horn, indicators, feed for ignition coils.

Can see a speed sensor input, what does it need to feed that?

Offline zombie365

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Re: CB400F Motogadget m.unit thread
« Reply #3 on: March 22, 2021, 12:47:51 AM »
Thanks for your reply K2-K6. :)

I'm unsure whether the m.unit has any oil pressure monitoring capability, although it does have some aux inputs that are configurable. I've had a quick skim through the manual an it doesn't seem to mention oil pressure, I could be wrong. however the Koso Speedo/clocks I'm going to use does have an oil pressure light. I may need to wire the existing sensor directly to the clocks. I'm guessing this is just one of the wires coming directly from the engine?

https://www.kosoeurope.com/en/speedometer/d64-custom-style/996/d64-custom-style-multifunctions-meter-black-10000-rpm-tuev-approved?c=3052

The m.unit came with a magnetic sensor and some tiny magnets that are meant to be attached to wheel. It is not necessarily needed for it to work, but is used to record mileage for servicing, travel distance ect.

I'm looking to use an analogue to digital speedo cable and rev counter cable to interface with the Koso clocks and hopefully splice the speedo output to interface with the m.unit.

https://www.digital-speedos.co.uk/speed-sensors-c9/daytona-cable-to-digital-converter-for-suzuki-and-honda-models-please-click-on-listing-for-models-covered-p794

Thanks

Sam
« Last Edit: March 22, 2021, 12:46:28 PM by zombie365 »
1977 Honda CB400F

Offline eight0

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Re: CB400F Motogadget m.unit thread
« Reply #4 on: March 22, 2021, 11:14:59 AM »
Oil pressure: You need an idiot light, it doesn't monitor oil pressure in the M unit, but you do run power to the light from Aux 1 or 2.

Speed sensor: Correct, This is just so the M unit can track your rides/service intervals. You split the signal wire from the sensor to the Gauges and to the input on the M unit.

Reg/Rec: As Brian says, you can't use the original reg rec units (edit: with a lithium battery). You should also not use a cheap eaby unit. I bought the Ricks reg/rec, expensive, but they are tried and tested.

This is the best diagram I have found, It's also editable in illustrator.  https://technicalarticles.revivalcycles.com/hc/en-us/articles/360009106131-m-Unit-Blue-Basic-Universal-Wiring-Diagram

side note: The M Button will not work unless installed inside steel bars, so if you are going aluminium clip-ons, don't buy one.
« Last Edit: March 22, 2021, 12:49:30 PM by eight0 »

Offline Laverdaroo

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Re: CB400F Motogadget m.unit thread
« Reply #5 on: March 22, 2021, 11:58:57 AM »
I know I’m a bit cheeky but I’ve to wire the same system bar the clocks to the Long Haired General’s bike next month, if I get the frame and engine back from the ‘coaters’.
Would you mind me jumping on here and firing in some questions as and when? I love the simplicity of the m unit, realise it’s quite expensive but really fancy the challenge. Hope it goes ok for you and I look forward to hearing how you get on👍👍👍
Mornings are the invention of the devil

Offline zombie365

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Re: CB400F Motogadget m.unit thread
« Reply #6 on: March 22, 2021, 01:28:38 PM »
I know I’m a bit cheeky but I’ve to wire the same system bar the clocks to the Long Haired General’s bike next month, if I get the frame and engine back from the ‘coaters’.
Would you mind me jumping on here and firing in some questions as and when? I love the simplicity of the m unit, realise it’s quite expensive but really fancy the challenge. Hope it goes ok for you and I look forward to hearing how you get on👍👍👍

yeah go ahead buddy, I was hoping for people to ask there questions, as it might give me an inkling of upcoming problems!
1977 Honda CB400F

Offline JamesH

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Re: CB400F Motogadget m.unit thread
« Reply #7 on: March 22, 2021, 06:50:55 PM »
THis video may be useful for your build: https://www.youtube.com/watch?v=NK0s6AHycdk&t=1996s

Offline zombie365

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Re: CB400F Motogadget m.unit thread
« Reply #8 on: March 22, 2021, 08:52:02 PM »
Oil pressure: You need an idiot light, it doesn't monitor oil pressure in the M unit, but you do run power to the light from Aux 1 or 2.

Speed sensor: Correct, This is just so the M unit can track your rides/service intervals. You split the signal wire from the sensor to the Gauges and to the input on the M unit.

Reg/Rec: As Brian says, you can't use the original reg rec units (edit: with a lithium battery). You should also not use a cheap eaby unit. I bought the Ricks reg/rec, expensive, but they are tried and tested.

This is the best diagram I have found, It's also editable in illustrator.  https://technicalarticles.revivalcycles.com/hc/en-us/articles/360009106131-m-Unit-Blue-Basic-Universal-Wiring-Diagram

side note: The M Button will not work unless installed inside steel bars, so if you are going aluminium clip-ons, don't buy one.

Thanks for your advice eight0, :-)

Good tip on the rectifier, I'm doing a bit of research on it now. I've seen that some people are using the reg/rec sold by 4into1 as well, it is also half the price of the ricks one...

https://4into1.com/regulator-rectifier-lithium-lead-acid-honda-cb350f-cb400f-cb500-cb550-cb750/

https://ricksmotorsportelectrics.com/Rectifier-Regulator-Lithium-Compatible-14_100

Has anybody used the 4into1 reg/rec? any problems with using lithium battery?

also, I'm not set on using an AG battery, I'm looking at some different brands as well. any suggestions welcome! :-)

Cheers


1977 Honda CB400F

Offline Laverdaroo

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Re: CB400F Motogadget m.unit thread
« Reply #9 on: March 22, 2021, 09:33:58 PM »
I've been watching this chap a fair bit, he was the chap I watched when I split and cleaned the carbs, it'd been a while and I thought his way of presenting the task and the ease, was fantastic.

I've yet to buy all the bits n bobs for the system and using the time to clean, paint, read etc As soon as I get my house sold there's gonna be a motogadget bill  coming i think!

cheers fellas
Mornings are the invention of the devil

Offline Laverdaroo

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Re: CB400F Motogadget m.unit thread
« Reply #10 on: April 03, 2021, 01:13:03 PM »
what id the issue with the antigravity batteries, are they failing quickly?
/
what would be an alternative, I cant find anything as slim on the net anywhere?   Im a bit stuck for space under the seat, thats all!
Mornings are the invention of the devil

Offline sye

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Re: CB400F Motogadget m.unit thread
« Reply #11 on: April 03, 2021, 01:21:36 PM »
Yuasa MF for me every time. Last for years, last one I put on my VFR 750 was still going strong 8 years later. There's a reason Honda fit them to their new bikes.

Offline zombie365

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Re: CB400F Motogadget m.unit thread
« Reply #12 on: April 03, 2021, 01:35:26 PM »
@Laverdaroo

I've just ordered the Aliant YLP09x

It's 8aH pretty much same dimensions as antigravity and half the price!

Sam
1977 Honda CB400F

Offline Laverdaroo

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Re: CB400F Motogadget m.unit thread
« Reply #13 on: April 04, 2021, 12:33:57 AM »
I'm with you on the YUASA, I've the same YT9BS in my VTEC that IK bought it with back in 2004, I think it might be  a record contentder..........and the original reg rec!

I need a thin one to mount on its side under the new seat pan so I was looking at the Antigravity ones. Sam that's a bit of a steal isn't it? Let me know what the verdict is when you get it in terms of robustness (if that's a word), only as I intend to mount it on is side. Top info though, cheers. Where did you order that from?......
Mornings are the invention of the devil

Offline Bryanj

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Re: CB400F Motogadget m.unit thread
« Reply #14 on: April 04, 2021, 12:51:27 AM »
The standard reg has a fairly "wide" charging range and puts the ag battery into a too high a volt charge which damages them and as Boeing found out can, in extremes, cause fires.
I have read that some of the more expensive makes of combined units do a different one just for these batteries that is set as high on charging volts

 

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