[Captain Bob]

Seems the person who originally restored my 1955 Indian Woodsman never really finished the job.  The carburetor was not properly set up (that seems to be sorted out now) and I am now finding the electrics may have not been tested as well.  Hence my question.  The 55 Woodsman was delivered originally with a 6v Battery and positive earth.  I do not know how this bike was wired when restored.  I am pretty sure it was set up as a 6 volt system but am not sure about the positive earth.  I did check some wiring and thought it was positive earth but now, I am not so sure.  I have no idea how the dynamo was polarized.  Here is my question...  The bike looks like it has the original control box.  Does that box care about polarity? I know it contains a couple relays but cannot find a diagram to determine what else it may contain.  I tested the voltage coming from the dynamo and it reads positive. Seems it is outputting 10 volts or so.  Meter leads are as follows...  Red lead on the dynamo, black lead on ground, Voltage read was positive polarity.  Is that telling me the dynamo is polarized for a negative ground?

Here are the symptoms...  With a positive ground, I turn on the electrics with the switch on the headlight.  The lights come on everything seems to be OK.  Ammeter is showing a drain on the battery.  It is not charging.  Voltage at the battery is 5.6 volts which is consistent with ammeter, clearly not charging even when the engine is revved.

The previous owner does not remember if it was a positive or negative earth.  I do not think he ever connected a battery to the system.  If I connected the battery in reverse polarity, what trouble would that cause?

I plan on doing some continuity checks to see just how this thing is wired. I am curious about how sensitive the control box might be to polarity and also if connected in reverse polarity, what have I potentially damaged?  Can I just repolarize the dynamo to the polarity of my choice and then connect the battery consistent with that choice and call it a day?  As usual, appreciate any and all thoughts!

[AzCal Retred]

Any pictures of the aforementioned device? Maybe these PDFs will provide some inspiration...?

https://www.rexs-speedshop.com/
https://www.rexs-speedshop.com/wp-content/uploads/2018/10/Motor-cycle-magdynos-MO1L-MN2L-Sec-L-5-Pt-B.pdf

http://www.southwalessectionvmcc.co.uk/
http://www.southwalessectionvmcc.co.uk/Library/Tech%20files/lucas%20magdynos%20workshop%20manual.pdf

I wouldn't get too creative with these pricey & hard to get items, you don't want to inadvertently "let the smoke out" and make things worse $$$... Better to PM AdrianII or Bullet Whisperer and get some real knowledge than just flail away. Magneto/Magdyno repair is a bit of black art, I'm sure that a lot of the parts must be hand made or adapted by now.
There's a reason all this electro-mechanical hardware was replaced by solid-state electronics. Fun when it's working though...

[Captain Bob]

Any pictures of the aforementioned device? Maybe these PDFs will provide some inspiration...?

https://www.rexs-speedshop.com/
https://www.rexs-speedshop.com/wp-content/uploads/2018/10/Motor-cycle-magdynos-MO1L-MN2L-Sec-L-5-Pt-B.pdf

http://www.southwalessectionvmcc.co.uk/
http://www.southwalessectionvmcc.co.uk/Library/Tech%20files/lucas%20magdynos%20workshop%20manual.pdf

I wouldn't get too creative with these pricey & hard to get items, you don't want to inadvertently "let the smoke out" and make things worse $$$... Better to PM AdrianII or Bullet Whisperer and get some real knowledge than just flail away. Magneto/Magdyno repair is a bit of black art, I'm sure that a lot of the parts must be hand made or adapted by now.
There's a reason all this electro-mechanical hardware was replaced by solid-state electronics. Fun when it's working though...

Thanks for the pdf's.  Good info on the magneto.  However, my issues revolve around the dynamo that provides DC voltage to the lighting system and recharges the battery.  I need to understand this system better.  Was hoping to get some time today to further check it out but, that didn't happen.  lol  I will spend time tomorrow however.  My main two questions are:

1 - Does the control box care about polarity?  This is the box that the dynamo directly connects to.  It has four leads two of which come from the dynamo.  I am guessing that it doesn't care about polarity whereas, you can set the dynamo either positive or negative ground without (I believe) changing anything on the control box.

2 - Can I just repolarize the dynamo to the polarity of my choice (Positive ground for instance) and then connect the battery consistent with that choice and call it a day?  I think I would just need to ensure the ammeter is wired to correspond to the correct polarity.

Pretty sure the juice coming from the dynamo is positive voltage.  This indicates to me that I should have the battery set up for a negative ground.  But maybe I am wrong.

[AzCal Retred]

You will definitely need someone raised/conversant with the particulars of the hardware.

In a generic sense, the dynamo is whirling conductors inside of a stationary magnetic field. These moving windings are carrying AC.

The commutator will have 2 brushes and "slots", a bar for each end of the winding, each separated by mica.

The brushes pick up the rotating windings at the precise time the voltage & polarity is maximum, (+) on one brush, (-) on the other. The commutator is a way to mechanically create DC voltage by picking it off the rotor at the right moment. These old boys were geniuses.

Polarity is generally dependent on direction of rotation or field polarity. The tricky bit is that the (+) lead configuration may be built into the design of the machine & not easily changed - But again, I don't really know these machines.

Voltage is regulated by varying stationary magnet field strength, which is achieved by varying the current thru the field windings. That's probably the second pair of wires. The old school regulators were electromechanical and required maintenance & adjustment. I think they just toggled on and off, "shot feeding" the battery. That would be easy, as infinitely varying field current requires an electromechanically ratcheted advance/retard rheostat, a much more involved process.

I can think of a lot of ways to "zorch" this device casually hooking it up & "Lessee what happens now". If it was mine, I'd be on the phone or e-mail to some "Olde Brits" shop and be crating it up. You don't know what others may have already done and you aren't a SME (subject matter expert) and you don't have any of the olde school voodoo tools (the "growler", commutator mica lathe, etc.) that were commonplace test tooling in 1920 - 1950. You don't have parts & have no way to know if the device is truly functional as is.

If this was a 1999 Bullet, I'd say have at it, nothing you could do would be beyond Hitchcock's purview to replace & you'd learn something. Unless you have a burning desire to be a dynamo tech and a time machine set for 1940, I'd send it off to someone that knows. AFTER you have a working unit with a functioning voltage regulator, THEN I'd do a little more research and some judicious poking around. The frustration avoided alone is worth it, one less thing to worry about. Just my dos pesos.

[Captain Bob]

So....  No fried wires today.  That was good.  I checked out the wiring.  It seems to be wired correctly. I can only assume it is supposed to be a positive ground whereas, (wired for positive ground) when juice is applied the ammeter shows the current drain.  If I were to reverse polarity, the ammeter shows charging which it clearly is not doing.   It is interesting to note however, the fuse is on the ground lead.  I would it would have been on the "hot" lead.  The control box appears to be brand new.  No stuck relays or anything I could see wrong with it.  Wiring to it seems good other than one wrong color on one of the wires.  I figured I would try re-polarizing the dynamo for a positive ground.  I did that then checked the output of the dynamo with the bike running.  She was putting out 10 to 11 volts negative which is what I would expect after re-polarizing it.  Reconnected wires to dynamo and started the bike up to check to see if it is charging.  No luck.  Ammeter shows a drain and lights do not get brighter when revving the engine.  So... I can only assume the control box is not functioning.  The question is, if the control box is brand new, would you normally have to adjust it after installation on a bike or, are they preadjusted?  Perhaps I need to adjust this control box to get it to do its thing.  More research is needed.  lol
Modify Message

[Captain Bob]

Hmmmm...  It just occurred to me.  This bike has been sitting for years.  I haven't considered cleaning the contacts on the relays in the control box.  Duh.......!  That could be my whole problem!  I will get to it tomorrow!

[richard211]

I have not worked on a magdyno Royal Enfield, but on the 1960's bullets they had a 6v alternator, those models had a positive ground. I referred a Lucas spares catalogue for 1955 Enfield motorcycles and the control box is listed as RB107. I did find a Lucas workshop manual for the RB 107 which might be helpful in adjusting the regulator.

[Captain Bob]

Richard211, Thanks Much!  That is very helpful.  I have been trying to find some info on the control box and this fits the bill precisely.  Going to try cleaning the contacts of the relay's today and see if that helps.  It just could be the bike has sat for so long the relay contacts may have corroded.  I did have that problem with the contact breaker points.  I needed to clean them before I could get any spark.  Again, thank you.  This helps a lot!

[richard211]

Happy to be of help, do let us know what you find.

[Captain Bob]

Sorry to take so long to get a progress report out.  Seems life kept getting in the way and then, I got sick.  Not sure if it was covid or not, I never got tested, but the symptoms were covid like.  I have already had Covid a few months ago.  Would be really surprised if I got it again so quickly.  Finally got through it however and had an opportunity to look at the bike this afternoon.  Did all the wiring checks involving the control box and found things to be in order.  I then cleaned the control box contacts and fired the old girl up.  Voila!  she was charging!  Seems the problem was just corroded contacts!  Love it when a plan comes together.  Don't know why I didn't think to clean the contacts first off.  Might have something to do with age.  lol   Anyway, took her for a short ride and all is good!  Thanks so much to all who contributed to this little project. Information I received was fantastic and of great help.  Now I need to determine why the kill switch isn't working.  It is a rather inexpensive button mounted to the handlebar.  Guess what I will check first?  You got it!  The contacts.     More to come.

[Adrian II]

Not sure if there ever was a factory kill switch with the Lucas magdyno, though some other magnetos had provision for them. With a Bullet you can stop the engine on the decompressor lever.

However, after-market points covers for use with kill switches definitely ARE available for the Lucas magdyno, see here. They will ship to the USA. Hope this helps.

https://www.themagnetoguys.co.uk/points-caps-with-cut-outs#Two

A.

[Captain Bob]

Not sure if there ever was a factory kill switch with the Lucas magdyno, though some other magnetos had provision for them. With a Bullet you can stop the engine on the decompressor lever.

However, after-market points covers for use with kill switches definitely ARE available for the Lucas magdyno, see here. They will ship to the USA. Hope this helps.

https://www.themagnetoguys.co.uk/points-caps-with-cut-outs#Two

A.

I just checked out The Magneto Guys website.  Very interesting.  Thanks for passing that along. I have no idea where the wire runs to with this kill switch.  I need to take a closer look.  I like the thought of just using the compression lever.  That simplifies things.  I may end up removing the existing kill switch.  We will see what happens after I take a closer look.

[Adrian II]

On the later Lucas SR1 magneto there's an obvious kill switch wiring point on an insulated stud in the side of the magneto body, I don't know what the O.P. might have rigged up to the magdyno, but one of the points covers I linked to would sort this out.

A.

[Captain Bob]

So....  after getting the charging system working, I am trying to debug the non-functioning kill switch.  there is a button on the handlebar that when depressed grounds a white and black wire.  The other end of that wire goes to a terminal on the Lucas ML01 Magneto.  This terminal is to the right and down when looking at the points cap.  Only problem is....  That terminal does not appear to be an insulated terminal but rather a ground (or earth).  I do not see any insulation whatsoever and, with the wires removed from the terminal, it measures a direct short to ground.  So, my kill switch button seems to be grounding a ground....   

Thoughts anyone?

[Adrian II]

OK, I guess you have a dummy kill switch system installed. Love it! 

Speculation mode ON.

Possibly the PO/restorer wasn't so clued in on magnetos, or else he started putting a kill-switch set-up together, only by the time he'd discovered that there was no obvious way of connecting it to the mag's low tension circuit, he gave up and just left it in for looks or fooling some equally clueless vehicle inspector. 

Speculation mode OFF

Anyhow, if you want a WORKING kill switch, you know what's needed.

A.