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I am at my wits end with trying to fit a functioning regulator, been two summers now trying to get the charging system to function, there is no one I can find with has any experience here in Canada.

The bike runs great until the battery dies, no DC charge getting to the battery through the regulator. I have converted the ignition to a Sasche system and it works very well, in addition I had the stator rewound by Westcounty Windings in the UK two years ago.

Since the original Ducati Electronics ignition was abandoned I did not have the ignition coil rewound. I have two wires coming from the rewound stator, with the engine running at idle, attaching a multi-meter at AC scale to the two wires I read 19.5 volts at idle, at 4000 RPM this climbs near 45 volts and at 5000 rpm I am reading 55 ~ 60 volts AC. Based upon these readings I assume the stator is functioning as it should??

I have reviewed the factory shop manual wiring diagram for the early and later 500 bikes and I believe I should be following the early diagram showing two wires from the stator to the reg/rec, a brown wire form switched fuse box to reg/rec and ground the body of the reg/rec to frame.

I have tried two Ducati Energia reg/rec units, both stamped 343142, and have terminals G G R+B C, I am connecting the two yellow stator wires to G and G and the brown to fuse box to C. Body of reg/rec ground to frame. I read online that the terminals marked R+B are not wired to the regulator circuit and are not used in this application. In this configuration neither reg/rec is putting out any DC voltage, regardless of engine rpm.

I also have a reg/rec that came with the motorcycle when I purchased it, there are no manufacturers marks on the cast body but there are fixed wires coming from the body, Yellow - Green - White - Red - Yellow. I connected the two stator wires to the two yellow reg/rec wires and the red wire from the reg/rec to battery positive, the green wire had an eyelet terminal so I assume this is ground, no idea what the white wire out of the reg/rec is for. I get no DC voltage readings out of this reg/rec unit.

I can find very little online to test the function of a reg/rec other than a mulit-meter on diode testing the G G terminals to the cast body with no readings present.







Am I missing something very basic or could all three reg/rec units be faulty????

Can I fit any single phase reg/rec unit to this motorcycle? I see several affordable single phase 12V reg/rec units on Ebay.

Canuck750 wrote: ↑29 May 2023 23:31

I have tried two Ducati Energia reg/rec units, both stamped 343142, and have terminals G G R+B C, I am connecting the two yellow stator wires to G and G and the brown to fuse box to C. Body of reg/rec ground to frame. I read online that the terminals marked R+B are not wired to the regulator circuit and are not used in this application. In this configuration neither reg/rec is putting out any DC voltage, regardless of engine rpm.

Never believe what you read on line!
For the 500 as standard it uses a two wire regulator, i.e single phase, you have to connect the R/B+ terminal to the battery generally via the fuse box.
The brown C terminal is for Control it supplies only switched 12V to the regulator to control its function, it does not supply current to the battery.

my crappy hand drawn diagram of this regulator can be found here, at the bottom of the page.
https://www.motomoriniclub.nl/tech.html

The standard Road bike 350 regulator system is different, do not refer to this. The off road 350/500 regulator system is totally different again do not read about this.

Hope this makes sense.

Any generic single phase regulator can be used but the wire colours may well be different, so its likely that for the generic regulator you didn't connect its control (switched 12V) supply this may have been the white wire.

Cheers
Mark

Thanks Mark!

I tried both my Ducati reg/rec units, connecting a red wire from R+B to battery via fuse box, brown from fuse box to C and the two stator wires to G-G and grounded the cast body to frame, still nothing coming out of the charging circuit on either. I also tried connecting the R+B direct to battery + terminal, still nothing on the DC reading above the battery slowly draining at around 11.8V.

While the engine was running with all the reg/rec connections made I tested the AC output from stator and it remains as before, around 20 V AC at idle then going up to 55 ~ 60 with the throttle opened up.

I also tried the stator I have with all the wires coming out of it two yellow to stator, red to battery +, ground to frame and I tried the white and green wires both the switch power on, nothing from the charging circuit.

I am at a complete loss, I have ordered a generic single phase reg/rec off Ebay, maybe all three of the reg/rec's I have are faulty??? Seems very strange that a unit I bought brand new from Mdina Italy is not working.

Hi,
Its certainly odd that none of the regulators is functional.

Apologies in advance for some basics - hope no offence but
Are you absolutely sure the regulator earth is connected, I have fixed various issues with restored machines where there is too much paint and there is no good earth connection back to the engine. For best practice I would earth the battery and the regulator to a common point.

Did you measure the presence of 12V on the C (brown wire terminal), the regulator wont work without it.
and really sorry to mention it but the Morini is negative earth....

The voltages you measured seem ok for an unloaded stator

The stator you have is not standard for the 500 though
The 500 stator does not have the red wire. It has 2 yellows, a green and a white. The white is just an earth, it is usually of thinner gauge, its not expected to carry lighting currents, but serves as a supplementary earth for the ignition system.

However we think that some very early 500s were sent out with the 350 style stator which has the additional red wire AND used the 350 road bike regulator.

In your case you can use the stator you have, and I assume it hasn't been messed about with as a single phase stator. Like this:
Please don't connect the red wire of your stator, just leave it taped up to avoid shorting, without the correct regulator you will discharge the battery through the stator windings.

Instantaneous battery removal with engine running can kill the regulators, later regulators often carry a warning sticker to this effect.

Mark

Thanks for the quick reply Mark!

West county Windings decided to rewrite the Stator with one yellow and one red lead for the AC charging group of 5 coils, no idea why. There is no green or white because the ignition coil was left off the Stator as the bike has been converted to a Sasche system with battery / coil ignition.

I did measure DC voltage at the fuse box take off point for the brown ‘C’ wire and it reads the battery voltage.

I have a ground from frame to the reg/rec body but to be sure the case is grounded I ran a temporary test lead from the reg/rec case direct to the battery ground.

I went ahead and ordered a cheap single phase reg/rec I found online from Spark Moto.

A retired motorcycle mechanic recommended I fit a Harley Davidson single phase reg/rec unit, they are the two pin type (2 AC leads) these are cheap and simple, reg/rec grounds to frame, only two AC leads and one long red lead direct to battery positive. Apparently he has used these in many permanent magnet rotors like the Morini uses.

I am going to go through the entire fuse box connections again. All the wire harness assemblies were replaced with new wires and connectors. As I mentioned the bike starts easily on the electric start, warms up quickly and runs smoothly. I can ride it for an hour but by then the battery drains down and if I shut it off I have to use the kick starter to get it going again.

Electrical is alien to me but I am slowly starting to understand it, what I don’t understand is why Morini used different types of reg/rec units? If the Stator is putting out 60V AC then why all the different types?

Canuck750 wrote: ↑31 May 2023 13:40 Thanks for the quick reply Mark!

West county Windings decided to rewrite the Stator with one yellow and one red lead for the AC charging group of 5 coils, no idea why. There is no green or white because the ignition coil was left off the Stator as the bike has been converted to a Sasche system with battery / coil ignition.

Ok, so the red confusingly has the functionality of the yellow, If I were you I would replace the lead with correct colour or at the very least put some yellow tape/heatshrink at the end to avoid confusion later.
I have been thinking whether there is a way that the stator could appear to be OK unloaded, but have been wound incorrectly. For sure the stator can drive without a regulator present a 55W standard incandescent bulb (across the yellows not grounded and no other connections)
60V a.c across the yellows at reasonable rpm like 3000 rpm sounds fine though, if you load it that will quickly fall.

Also can you make sure that neither of the yellows is shorted to ground in the stator.

The stator winding method is uncommon. Normally these kind of stators as fitted to countless Vespas have 4 lighting coils, 1 CDI generator coil and 1 crank pickup coil. In the Morini case there is no pickup coil and there are actually 10 lighting coils (it has to be an even number) each former has 2 coils each wound in opposite directions, so 5 formers are used. This is really important to balance the windings and have a balanced a.c generator.

The regulators are not unique to Morini, in fact the same Ducati Electonnica regulators both single phase and two phase are used across countless Italian scooters, small motorcycles and Ducatis such as Pantahs and even the MHR has the same regulator as the 500. The only differences really are the current load capability. The Ducati regulators are actually very efficient as they contain a thyristor controlled bridge, to achieve this a switched 12V supply is needed. This is a very common circuit now 50 years later, but as a comparison what regulator method was a Norton Commando of 1972 using?

The 2 phase regulator as used on the road 350s was in the 1970s considerably cheaper to manufacture as it contained only 2 thyristors, rather than two thyristors and 2 diodes as per the single phase regulator, of course with todays electronics costs this would not be such a consideration.
The 500 has a generally lower rev range than a 350, therefore to get better charging the single phase system was adopted.

Mark