Calling the Electrical Gurus

thenarrowboatman

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Ref Post 1974 TXA Regulator
I have a long standing fondness for MZ two strokes. My ETZ251 might be very ugly but has been exceptionally robust and reliable, standing idle for months then starting third kick and taking me away for the weekend with little trouble. The widely excepted replacement for the mechanical regulator on the 15Amp B type alternator is a 3 pin electronic unit variously designated Cargo130675,MobilletronVR-B191,LucasNC403 etc.

This unit can be purchased for less than £10 in the uk and is widely available.(BMW, MERC, VOLVO etc)
It has just 3 pins F=DF,GND=D-,IG=D+

I turned to mechanical engineering because I could not grasp the fundamentals of electrics. I have tried to educated myself again recently on the NET but I am finding the non standard nature of automotive charging systems very frustrating.

( Don't get me started on standardization and making the world a easier place to be )

So I'm thinking if I connect the TXA wires as follows
RED to D+
BLACK to D-
GREEN to DF
Will I have regulation or burnout.

MZ wiring diagram
WIN_20210514_09_32_23_Pro.jpg
MZ connection of 130675etc
Screenshot_2021-05-14 MZ 12 Volt Electronic Regulators.png
 
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Cant see on the picture and dont know the wiring
What I do know is that if you connect them wrong they are quick to Fry
I have a Bosch type 3 pin on my bike now But the pins are not located the same on all these variants
They can be flipped.
I have a Laboratory power supply so I can hook them up with a lamp and slowly and carefully power it up to see what pin does what
Ground pin is easy to find with a resistance meter
And then the other 2 can differ The D+ and Df and D- should be standard names
So most likely it with small reservations will work
Provided it is large enough electrically to take the Heat so to speak
15 A can be to small since the main Fuse is 20 A
 
Jan-P thanks for your thoughts.
My haynes manual gives the output for the early Hitachi LD115 alternator on my TXA at 11amps @ 2000rpm.
Since the MZ manual indicates alternator output is 15amps (@rpm?) I was hoping there would not be any problem there?
This is where my electrical understanding fails me. So at higher rpm the TXA alternator could delivery nearer to 20 amps?
Or is it the case the alternator will try to delivery what the load wants and burn itself out in doing so?
 
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Jan-P.
Is your bike an xs650 1970-1979 ( type B alternator )?
What is the number of the Bosh regulator you are successfully using?
Cheers
Tnbm
 
The MZ rectifier has 2 sections. Not sure why lower section to headlight or ignition coil?

mz2.jpg
 
Thanks gggGary.
What is complicating the TXA/MZ comparison for me is the MZ has three extra diodes 'diode -trio'? powering the 61 connection to the charge light and standard mechanical regulator (as per the diagram).
Is the output from the MZ rectifier at D+ and 61 not the same?

Like I've said my electrical understanding gets muddled.
 
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I am on my way out right now but the one i have currently was bought from the UK before you Skipped the EU

Woods auto --VRG3639

Should be that one --it looks different
https://www.woodauto.com/product/VRG3639

I have a bike with points originally it is a 1980 but with points and mechanical regulator at the beginning.
I am hesitant to give advice since i am no Expert and mistakes can be Costly
I have used these types for I guess more than 10 years .But mostly if not always with another Rectifier
Originally I used a SAAB Car Setup ..including a Warning lamp so yes it is doable .

Since you are in the UK I suppose you can call them and get the pins and specs Right.
I am going out for a while but will check in later.
When it comes to specs ..I go for larger ..giving some margins for Mishaps and Spikes
Always there on an Old XS 650 .Regulators and Rectifiers are not fine tuned objects
a rectifier 35 A Will do the same job I do believe as a 15 A .But the first wont fry at a spike of 22 A
Again I am no expert I did this when on my first bike a $ 800 Needed alternator parts a $350
I fumbled with these things.
And over the years found solutions ---- :here on the forum is a I believe Fiat part that is a working solution.
Ill check in later
 
Somewhere in the dark dusty recesses of my mind is an old school discussion of single vs. three relay voltage regulators but that may have been for controlling generators not alternators. ( old, school) in the literal sense. LOL
 
Jan-P thanks again.
The vr3639 looks like what I've been considering.
For confirmation your 1980 has alternator field coil power regulation rather than ground regulation.
Much appretiated
Tnbm
 
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Somewhere in the dark dusty recesses of my mind is an old school discussion of single vs. three relay voltage regulators but that may have been for controlling generators not alternators. ( old, school) in the literal sense. LOL
Gary I think you are thinking of a regulator for a 2 brush generator. It has 3 sets of points. Heavy one for cut out, another one to limit voltage and a third one to limit current. 3 brush generator regulators only had 2 sets of point. Cut out and voltage limiting. The 3rd brush on the gen was set to limit current.
 
Jan-P thanks again.
The vr3639 looks like what I've been considering.
For confirmation your 1980 as alternator field coil power regulation rather than ground regulation.
Much appretiated
Tnbm

Mine is the pre 1980 System ..Not sure if I understand the English right
But there are before 80 and 80 and after But mine is a XS 650 1980 SE US Custom
But I don't know why it has the pre 80 alternator system I am 100 % certain
that. it has.
Since i ordered a regulator and rectifier for a 1980 and after That fried ..
And I had to figure it out.
I believe there was a gap there so some European 1980 .s had the older system.
If you live in a city it might be available over the Counter.
Since these were common .Not so much now.
 
Brillant Jan-P
You have helped me on the way. Am I right in thinking if I connect the regulator wrong I am going to fry it and not the field coil/rotor?
Thanks very much
Tnbm
 
Brillant Jan-P
You have helped me on the way. Am I right in thinking if I connect the regulator wrong I am going to fry it and not the field coil/rotor?
Thanks very much
Tnbm

The exact answer to that is I don't know.
Here are the risky parts ..even with stock electronics fex Suzukis.
The regulator is a black box with unknown internal failure modes.
It can go short circuit or open circuit. Transistors most likely.
Most likely open circuit.
And stop the charging But It depends on the internals of the box.Which we at this point in time knows nothing about
And not even should it be here on my table since it is packed in epoxy or so.
Often with unmarked components inside
But generally speaking the same regulator is used in cars and they don't either want to accept a Alternator failure if the regulator
fries.
So the extra care in hooking it up. And then check functionality.
Across battery. Immediately.
But still no guaranties.
But again a well known solution that has existed for a long time
And you don't buy at a flea market.Or online dirt cheap.
From a company in a back alley in Canton.
But instead from a Serious Auto Supplier. That has been around a while.
Getting info on what pin goes where.
But no guarantees.
We also have the magical thing called " The Fuse "
That should save the day if the Regulator fries in the garage. Shorting trough.downsize that.
I think it will work ..with extra care connecting.
We here can give info.


.
 
Jan-P
Morning, Over the weekend found I had a CARGO 130675 in my MZ spares box. Tried it,briefly, it worked. Noted your fuse suggestion which is a wise one I'll incorporate if i decided to use the 130675 (or alike) permanently.
If I=V/R then rotor amps=14.5v/5.5ohms=2.6A??
Would a 5amp fuse in the green wire between rotor and regulator offer the required protection.
Thanks again for your time and advice.
Tnbm
 
Jan-P
Morning, Over the weekend found I had a CARGO 130675 in my MZ spares box. Tried it,briefly, it worked. Noted your fuse suggestion which is a wise one I'll incorporate if i decided to use the 130675 (or alike) permanently.
If I=V/R then rotor amps=14.5v/5.5ohms=2.6A??
Would a 5amp fuse in the green wire between rotor and regulator offer the required protection.
Thanks again for your time and advice.
Tnbm

Need to think about this not heard of a fuse there .But it can be a good idea.
And if so how big it should be. If it is the duration of ON time --- or a sudden short
Or a too high voltage.

The cargo 130675 is as it seems something alike.
Perhaps is a plug in.
What I would do since it did not fry at your test
A quick googling to see what ratings and specs it have.
And then hook it up Measure the voltage across battery.
Revving a bit ..Then turn on lights and flasher and stuff see if it regulates. Measure again
I don't know that brand off the regulator I don't usually buy things where I see it used on car .Brands from Spain / Italy / France.
Might be old Fashioned :But here we can have snow ice and water at the same time.
Not all southern European solutions ( Fiat / Alfa Romeo .. etc ) can cope with that so good with that. So as a general rule I avoid it as much as possible..
Bosch on the other hand have a good reputation but are expensive.
But it ( cargo 130675 ) might be the solution.
Have not had time now to google that much So please be careful
But my guess is that it will work and is of a bit lesser quality than others out there :But can still be good enough.
 
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