Charging system troubleshooting question

Mike40M · Mar 22, 2020

I might be wrong, but I think I read somewhere a couple of days ago that overtightening the zener kills it.
In your first post you said that system voltage was less with engine running than with stopped engine.
You've also found that the alternator is lighting a headlamp (?) bulb at low revs.
To me it looks like the power from the alternator don't reach the battery. The battery is then drained by the ignition system.
Two possible reasons. Either a bad connection restricting current flow, or loss by current going another way to earth.
Being a lazy bastard, I should replace the rectifier and zeners with a modern regulator/rectifier. Did it last week on a BSA. But found that it started easily and worked well in emergency mode with the MC2 capacitor and disconnected battery. Not charging when battery connected. Problem solved, faulty ignition switch.

htown16 · Mar 22, 2020

IMHO if you have any doubt about the rectifier replace it with a Podtronic or similar unit. The Podtronic also handles the overcharge so no zener is required and should be disconnected or removed.
http://www.podtronics.net/

dynodave · Mar 22, 2020

Arlen Johnson said:
Where can I get a modern combined regulator/rectifier?

Get a 3 phase system for the challanged MKIII Estart single phase 180W system or you'll be into it again...later for more $$$$

Arlen Johnson · Mar 22, 2020

I see that AN has several. The two combined regulator/rectifier models are the first two on this page:
https://andover-norton.co.uk/en/shop-drawing/152/basic-electrical-equipment

Is my system a single phase or three phase?

L.A.B. · Mar 22, 2020

Arlen Johnson said:
Is my system a single phase or three phase?

Single-phase (180W RM23).

dynodave · Mar 22, 2020

Mike40M said:
I might be wrong, but I think I read somewhere a couple of days ago that overtightening the zener kills it.
In your first post you said that system voltage was less with engine running than with stopped engine.
You've also found that the alternator is lighting a headlamp (?) bulb at low revs.
To me it looks like the power from the alternator don't reach the battery. The battery is then drained by the ignition system.
Two possible reasons. Either a bad connection restricting current flow, or loss by current going another way to earth.
Being a lazy bastard, I should replace the rectifier and zeners with a modern regulator/rectifier. Did it last week on a BSA. But found that it started easily and worked well in emergency mode with the MC2 capacitor and disconnected battery. Not charging when battery connected. Problem solved, faulty ignition switch.

The bike sitting static shows battery voltage 12.8 which is OK. Once you start the bike the ignition is drawing the battery down 12.5 that equals no charging at all.....

dynodave · Mar 22, 2020

While not a totally fair comparison this 180W 3 phase still improves over a 180 single phase...especially in low rpm out put

Charging system troubleshooting question

Tornado · Mar 22, 2020

Lots of reg/rec options, several from Podtronics, Lucas, Sparx etc. Some have built in capacitor so you can dispense with the 2 MC stock unit if no longer working...this allows starting the bike at low/no battery (for kick starting obviously).
If you elect to go with the 3-phase setup, not you need the alternator and the reg/rec to be 3 phase.
I'd say if you were happy with the stock setup, single phase alt then keep it and just get an appropriate reg/rec for it...assuming your original zener/rec setup is the problem.
Here's a US vendor that sells different types:
https://www.classicbritishspares.com/search?q=rectifier

Arlen Johnson · Mar 22, 2020

You guys are the greatest! I thank you all for your help. Now I have lots to think about and decisions to make. I'm going to clean all the connections, put everything back together with my current stuff and see if it works. If not, I can buy the more modern equipment some of you have suggested. I'll "sign off" for now, but will be back soon with more reports (and maybe questions).

L.A.B. · Mar 22, 2020

Stator output (AC) also goes to the assimilator (one output wire on early Mk3s with the 3AW, both outputs on later Mk3s) so it might be worth checking the wiring to the assimilator and test with the output(s) disconnected.

Arlen Johnson · Mar 22, 2020

L.A.B. said:
Stator output (AC) also goes to the assimilator (one output wire on early Mk3s with the 3AW, both outputs on later Mk3s) so it might be worth checking the wiring to the assimilator and test with the output(s) disconnected.

What is the assimilator? Do we have a different name for it here in the States?

Tornado · Mar 22, 2020

Arlen Johnson said:
What is the assimilator? Do we have a different name for it here in the States?

It's the device that works with the charge warning light.

L.A.B. · Mar 22, 2020

Arlen Johnson said:
What is the assimilator? Do we have a different name for it here in the States?

No, but it's also referred to as 'warning light unit' or 'simulator' in manual section J8 also 'Ignition warning light unit' on the main wiring diagram.

dynodave · Mar 22, 2020

Tornado said:
I'd say if you were happy with the stock setup, single phase alt then keep it and just get an appropriate reg/rec for it...assuming your original zener/rec setup is the problem.

If you do a lot of lower RPM riding(non highway) with a 21T front sprocket (low battery charging) AND you run a headlight (higher battery discharge) your bike may eventually strand you on the side of the road......happy now !!!! Best cure 3 phase $$$$ OR put all low current LED light electrical load...$$$

The first 2000 approx MKIII norton used the old style thermo-mechanical warning light control (assimilator) from then on, norton changed to electronic light control to indicate low charge output.

Mike40M · Mar 22, 2020

I'm aware that you Americans are as keen on buying locally produced items as the English are about buying British. But I know that the Podtronics can affect some electronic ignitions, though solved with a filter.
I use the A Reg One from http://www.norbsa02.freeuk.com/goffyelectrex.htm which so far has worked well and is fairly cheap.

Arlen Johnson · Mar 22, 2020

Mike40M said:
I'm aware that you Americans are as keen on buying locally produced items as the English are about buying British. But I know that the Podtronics can affect some electronic ignitions, though solved with a filter.
I use the A Reg One from http://www.norbsa02.freeuk.com/goffyelectrex.htm which so far has worked well and is fairly cheap.

I have bought most of my parts (a couple thousand $$) from AN. It’s my “go to” source for Norton parts.

MichaelB · Mar 22, 2020

dynodave said:
Original is definitely 1/4-26 bsf but the thread is so soft is mushes easily and I suspect the factory may have cross threaded routinely with 1/4-28.
They are very often messed up.
thread pitch gauge at the original end tells the story....
As normal AN changes stuff and folks take it as "to original specs"...wrong again.

The lucas zeners were matched (close?) by "lucas power base" 3 phase system where the two zeners were in parallel.

can't type fast enough to keep up

I will confirm this. I pulled the one on my 72 Project, Bitsa. It measured 28 Where the nut sits
Further in on virgin thread, 26 TPI.
Someone has installed. 1/4- 28 and changed the thread.
Lesson learned.

RoadScholar · Mar 22, 2020

Integrated reg/rec units are readily available here in the states, as are 3 phase alternator kits. No good reason for paying high freight prices.

I have been told by sources that I trust that the new zenners that are currently available are not worth having. I made the assumption that the stand alone replacement rectifiers are of equal quality, I can't say for sure, but I'm not looking back in either case. Period zenners have 1/4-26 stud threads, available replacements are most likely to be M6 x 1.0; you can strip a 1/4-28 onto either, unfortunately.

If your wiring harness is the original you can start with breaking and cleaning ALL connections from the headlight to the tail light; this will, at least, buy your harness some time, but consider starting an escrow account for a new harness (while they last). Your switch gear would like their contacts cleaned and internal solder joints examined. There is absolutely nothing wrong with Lucas electrics; 40+ year old cars with original wiring have the same issues.

If this all gets too confusing PM me and I'll help you get this sorted.

Best.

MichaelB · Mar 23, 2020

Not to belabor this but I thought I'd post this pic.
The first 3 or 4 threads match up on the 28, then off it goes.
Didn't get a pic with the 26.

Arlen Johnson · Mar 23, 2020

MichaelB said:
Not to belabor this but I thought I'd post this pic.
The first 3 or 4 threads match up on the 28, then off it goes.
Didn't get a pic with the 26.

Back in 1960 or so, when I was a high-schooler with a Triumph TR6 Trophy, I heard about the British Whitworth thread system, but haven't thought much about it since. When you posted about the 1/4-26 thread on the Zeners I thought you must be mistaken. Fortunately, I didn't make an ass out of myself by saying you're wrong. Instead, I looked into it and...low and behold, there really is such a thing as a 1/4-26 thread...go figure. I intend to find and print a chart of all the British thread systems that were used then and now, and compare and contrast the various sizes. It turns out the 1/4-26 is in the British Standard Fine (BSF) system, not the British Standard Whitworth (BSW) system. It gets more involved because there are at least three more British thread standards: British Standard Cycle (BSC or BSCy), British Association (BA) and British Standard Pipe (BSP) All are mentioned in Wikipedia.

Charging system troubleshooting question

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