Regulator wiring help for use with Motogadget M-unit. Please Help.

Well, you're right. That's not a good place for it. There is a constant charge from that post to the ground. Weather the key is on or off. So now I'm at a loss as to where to put it though. Should I splice it into the Aux, or should I splice it into the lock? Does polarity matter here?
 

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Thanks Rich. What I am not is an electrician.... ;)


The lock is based off of a positive ground, that's how the m-unit describes the lock input in the manual. Isn't the black wire from the RR a negative?

Actually I think I may have answered my own question in trying to phrase the question here. And you were right all along, I need to splice it into the lock input, after the key...

Any confirmations?
 
I tested the connection at the m-unit. Looks like that is the answer. I need to splice the black wire in to the wire coming from the ignition switch(key), and going into the m-unit. This wire meets the needed criteria.

Electrical has never been something that I can easily wrap my head around. Thanks for the help all. I'll post how it goes.
 
Anybody know which hole the black wire had gone to in the connector at the key? I'm thinking about trying to fish a new black wire up to there instead of splicing my other wire.
 
Strange that none of the posts in the key connection offer the needed criteria... I may have to splice into the wire coming into the m-unit...

Thanks Sonreir. Please do let me know what you find.
 
Yep. None of the other posts had switched power to them. SO I connected it right at the terminal of the m-unit. Bike seems to run fine. As things progress I'll report back.

Thanks for all the input everyone.

Todd
 
Just ran it about 20-30 miles. Everything ran great. Started right up and had no problems. :)

Tomorrow is carb syncing and a tuning. I'll post pics in the next two to three days as it's in nicer locations and feeling good. I've got an instagram account that will surely have some more of the fun pics. Find me by searching my user name- H2Otoad

Thanks again all.
 
For sure you have it hooked up right; idk what they meant by positive ground as the diagram you posted clearly shows negative to be ground. The black wire going to the reg/rect is not negative (i know confusing right?) The regulator uses this wire to sense the battery voltage (positive) so it knows how much juice to make.
 
johnson_steve said:
For sure you have it hooked up right; idk what they meant by positive ground as the diagram you posted clearly shows negative to be ground. The black wire going to the reg/rect is not negative (i know confusing right?) The regulator uses this wire to sense the battery voltage (positive) so it knows how much juice to make.


I appreciate the clarification. It makes me feel better about how it's hooked up.
The positive ground that it mentions is simple. The rest of all the wires go from the m-unit to a frame ground- negative... But the lock/ignition goes from the m-unit and back to the positive. Take a look at the lock on the diagram I posted.
However what you have said twice now, makes perfect sense and is exactly in line with the positive ground that the lock works off of. For not knowing electrical, and not being so great with it. The m-unit was really easy to install.

Thanks
 
I think the point is that what you're taking about is not a positive ground. :)
 
Yeah. That's just what they call it in the manual, as it's going to positive, instead of negative....
 
Hi Todd,

Thanks for keeping this thread so informative throughout the pages by updating all of your thoughts and finding! I rode my CB750F '81 rebuilt cafe racer for the first time yesterday after making a new wire harness with m-unit and ran into the exact same problem.

Luckily I kept my home-made wire diagram which showed I did nothing with the black R/R wire, so I am going to hook it up to my Lock input this evening. Did you splice in the wire into the lock input wire or did you combine them in the connector at the terminal?

Again, thank you for helping someone 4 years later!

Cheers,

Dax
 
Dax, I don't really recall exactly how I ended up fixing the issue I had, but I do have the final diagram that I made for the bike and the harness I designed around the M-Unit. I'll post it here as an attachment. I also never just stuck wires into the terminals of the M-Unit, but instead would use these crimp on pins that would go into the terminals, sometimes I would have more than one wire per pin though. I hope this helps.

Todd

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Sorry to bring up an old post.

But I'm just about to tackle this whole process.
Building a new harness and just wanted to know if you have any tips that I would find helpful?

Many thanks

Sent from my SM-G955F using Tapatalk
 
Hey man, I have just finished wiring up my bike (1980 CB900F), I ran into the same problem with the black wire from the reg/rec and ended up running it to the AUX on the M-Unit as its a switched 12V source and I don't have a key ignition anymore because im using the M-Lock.
I butchered a wiring diagram I found online and tried to make it reflect what I have done on the bike, mainly so I could track down where I messed up because the bike is not charging the battery. Here is the link to the page I put it up on.

http://www.dotheton.com/forum/index.php?topic=75073.msg892440#new

I just got the battery tested and it has dropped a cell, Im going to get a new battery tommoz and chuck it in and fire up the bike and see if its charging. If its not then that wire diagram will prob have to change because I must have done something wrong!
 
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