Faulty Stator perhaps?

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velojames
Posts: 9
Joined: 19 Apr 2025 09:26
Location: SY7 8AU

Re: Faulty Stator perhaps?

Post by velojames »

Thank you gentlemen for your input.
So, with the parts on the bench, including the battery of course, I have 12 volts from the stator to the regulator. If the regulator passes this straight through, as it appears to be doing, this would seem to indicate a faulty regulator from what you say.
On the other hand, it is a brand new AO regulator which passes all the diode checks done on it.
There have been no comments on my suggestion about the stator only being connected to the battery after the key is ON and taking the regulator output straight back to the battery. Is that because it is too idiotic to consider and, if so, why?
Anybody got a good working Morini regulator they would be prepared to lend me to check things out?
Steve Brown
Posts: 1639
Joined: 12 Nov 2007 23:44
Location: Leicestershire

Re: Faulty Stator perhaps?

Post by Steve Brown »

An Al Osbourne regulator? They are for dynamo systems only, your bike has an alternator. I'll take look at AO website to see if they do what you need, which is s rectififer/regulator.

EDIT! OK ignore what I said above-AO do the right thing nowadays so panic over. (My panic that is) :oops:
All donations to the rest home for old Camels, Leicestershire.
MickeyMoto
Posts: 2711
Joined: 22 Nov 2008 17:41
Location: Even further oop North

Re: Faulty Stator perhaps?

Post by MickeyMoto »

velojames wrote: 13 Oct 2025 09:21 Thank you gentlemen for your input.
So, with the parts on the bench, including the battery of course, I have 12 volts from the stator to the regulator. If the regulator passes this straight through, as it appears to be doing, this would seem to indicate a faulty regulator from what you say.
On the other hand, it is a brand new AO regulator which passes all the diode checks done on it.
There have been no comments on my suggestion about the stator only being connected to the battery after the key is ON and taking the regulator output straight back to the battery. Is that because it is too idiotic to consider and, if so, why?
Anybody got a good working Morini regulator they would be prepared to lend me to check things out?
The other option being that the diodes are back to front and passing current through to the regulator! However, I do not have a wiring diagram for the rectifier and no idea how it works. There may be one on the nederland club pages accessible from this site.

All I know is how mine operates.

Edit:

Is this the one? http://www.aoservices.co.uk/products/a-reg.html
BumbleBee
Posts: 212
Joined: 13 Jun 2017 21:10
Location: Reading

Re: Faulty Stator perhaps?

Post by BumbleBee »

I believe with the standard reg. rect. the stator windings are live all the time even with the engine not running and the key out. Some people used to introduce fuses in case of faults.
Donkey's years ago I did sit outside a pub with some other MRC members and watch as my bike stated to smoke from the air ducts around the stator and later found that it was the dodgy old stator I had fitted, which decided to short to "earth" as we sat in the beer garden admiring the Morinis. The stator cooked itself and I had to fit a better one, no problems ever with that one. My point though; As it was live all the time it was possible for it to do what it did.
velojames
Posts: 9
Joined: 19 Apr 2025 09:26
Location: SY7 8AU

Re: Faulty Stator perhaps?

Post by velojames »

Thanks Bumblebee,
That must have been a moment of panic I daresay.
It seems that it has been firmly established that the stator is always live and that 12 volts appears on both yellow leads whether the bike is switched on or not. Now, my new and double checked regulator is passing this straight through. Do original Morini regulators (Ducati?) not do this? Now I am not sure if my regulator is OK or not.
Anyway, thanks to everyone who has sent advice. I will have do do more thinking.
velojames
Posts: 9
Joined: 19 Apr 2025 09:26
Location: SY7 8AU

Re: Faulty Stator perhaps?

Post by velojames »

Missed the additional query from Mickey about the make of reg. Yes that is the one. I believe I mentioned earlier that the wiring is Not according to the incomprehensible Morini diagram but to one of Rupert Paul's diagrams.
MickeyMoto
Posts: 2711
Joined: 22 Nov 2008 17:41
Location: Even further oop North

Re: Faulty Stator perhaps?

Post by MickeyMoto »

BumbleBee wrote: 13 Oct 2025 12:25 I believe with the standard reg. rect. the stator windings are live all the time even with the engine not running and the key out. Some people used to introduce fuses in case of faults.
Donkey's years ago I did sit outside a pub with some other MRC members and watch as my bike stated to smoke from the air ducts around the stator and later found that it was the dodgy old stator I had fitted, which decided to short to "earth" as we sat in the beer garden admiring the Morinis. The stator cooked itself and I had to fit a better one, no problems ever with that one. My point though; As it was live all the time it was possible for it to do what it did.
Electric Start models have an in line fuse. The battery is connected to the starter solenoid and is teed via a fuse to the fuse box and teed to the ignition switch and alternator. Yes, the windings are live all the time, bear in mind before removing the stator. Don't ask me how I know 😀!
MickeyMoto
Posts: 2711
Joined: 22 Nov 2008 17:41
Location: Even further oop North

Re: Faulty Stator perhaps?

Post by MickeyMoto »

velojames wrote: 13 Oct 2025 17:17 Missed the additional query from Mickey about the make of reg. Yes that is the one. I believe I mentioned earlier that the wiring is Not according to the incomprehensible Morini diagram but to one of Rupert Paul's diagrams.
The Morini diagram is quite simple. Just need a magnifying glass!
BumbleBee
Posts: 212
Joined: 13 Jun 2017 21:10
Location: Reading

Re: Faulty Stator perhaps?

Post by BumbleBee »

With the standard system; When the ignition is off and the engine isn't running the voltage from the battery comes through the standard reg. rect. and imposes itself onto the stator (Yellows and Red). It doesn't reach the part of the stator thats for the ignition (Green and "Earth") that is a totally separate system that runs on much lower voltages and would be damaged by battery voltage.
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