1967 V7 700 charging issue (regulator)

[rutgery]

Hey all,

I'm currently having some issues with the old marelli charging system on my old v7 700. It's fitted with the mirelli dynamo and the original mirelli regulator. The bike doesn't charge unless I jump a cable once from the positive terminal to the stator of the dynamo ( or DF on the regulator (No. 25)). The dynamo gives off up to 2.5V on its own, which I believe should trigger the regulator to supply the stator with it's DF output.

This doesn't happen unless I boost it with a lead once, which powers the stator and increases the dynamo output to 13.5 V. Then, the regulator acts as normal and supplies the stator on it's own. Has anyone else had this issue and/or does anyone know the intended treshhold for the regulator to start supplying current to the stator?

Edit: I also have a Bosch regulator, am I right in thinking that this should work as well with the mirelli dynamo? According to the wiring diagram on the Bosch regulator it should wire up the same.

[Kiwi_Roy]

 
http://www.thisoldtractor.com/guzzi007/schematics/1967_V700_USA.gif

Hang on a minute, are we talking generator like my old Loop?
The regulator is more a mechanical thing with coils and relays?
A typical generator holds some residual magnetism which kicks things off
 

[Old Jock]

Same as Roy I don't know bikes of that vintage.

Charlie will probably be able to point you in the right direction

From your diagram and looking at a V700 diagram, I assume that's it equipped with a Dynamo

From Carl's diagram it looks like the Stator is flashed via the charge light, if that light is out that's why you need to manually flash it, as Roy said an LED is no use unless you also added in a resistor in parallel

I'd go over the connections and pay special attention to that charge light. It's odd that you need to flash it manually and then it all works, if the light is illuminating as it should and it's the correct wattage and not been modified then that should be doing the flashing for you.

However I'm not a Dynamo guy I know very little about them beyond the basic theory

Wait to see if older wiser heads prevail

John

[Kiwi_Roy]

Yes John I think we are talking Generator, not Alternator, my mistake sorry.
I don't think the charge light is so important with a generator.
I really only know the Bosch or Lucas generators I have never seen a Marelli one.
Have you checked the brushes lately?
Sometimes the field coils can break down to ground

[rutgery]

http://www.thisoldtractor.com/guzzi007/schematics/1967_V700_USA.gif

Hang on a minute, are we talking generator like my old Loop?
The regulator is more a mechanical thing with coils and relays?
A typical generator holds some residual magnetism which kicks things off

Year that’s exactly the wiring on my bike! Interesting about the magnetism, do you think that the regulator not being used for this long could be the cause? Also, how would the battery not drain if that’s the case? As there would always be a current throug the stator?

Just to clarify, a dynamo would not make use of the charge light to jump the stator right?

[Kiwi_Roy]

A generator regulator also has a cutout relay that disconnects it from the battery
When you say you flash the generator is it just once in the day or do you have to do it every time you stop?
Strictly speaking a generator has an Armature and Fields no stator
The power is generated in the armature and rectified by the brushes, the field strength controls how much the armature produces.
Usually the only time you have to flash a generator is if it has been apart and lost its magnetism, sometimes it will start up with the wrong polarity.
I wouldn't like to say that the charge light never has to bump start the generator but the ones I am familiar with typically start by themselves, mind you I have never tried my loop without the lamp
even though thats an LED.
When I was an apprentice we fixed hundreds of generators for our work mates, we would typically run them as motors to test, occasionally if you ran one with the wrong polarity they would need re-flashing, back then some cars were positive, some negative ground.
The field insulation sometimes breaks down to ground, they are quite easy to re-insulate with linen tape.
Examine the commutator for any sign of uneven commutation like sparking at a particular spot, this is usually a short in  the armature, we used to use a growler to test for that.

I ask again, once you have flashed it is it ok when you stop or do you have to do it every time?

[rutgery]

A generator regulator also has a cutout relay that disconnects it from the battery
When you say you flash the generator is it just once in the day or do you have to do it every time you stop?
Strictly speaking a generator has an Armature and Fields no stator
The power is generated in the armature and rectified by the brushes, the field strength controls how much the armature produces.
Usually the only time you have to flash a generator is if it has been apart and lost its magnetism, sometimes it will start up with the wrong polarity.
I wouldn't like to say that the charge light never has to bump start the generator but the ones I am familiar with typically start by themselves, mind you I have never tried my loop without the lamp
even though thats an LED.
When I was an apprentice we fixed hundreds of generators for our work mates, we would typically run them as motors to test, occasionally if you ran one with the wrong polarity they would need re-flashing, back then some cars were positive, some negative ground.
The field insulation sometimes breaks down to ground, they are quite easy to re-insulate with linen tape.
Examine the commutator for any sign of uneven commutation like sparking at a particular spot, this is usually a short in  the armature, we used to use a growler to test for that.

I ask again, once you have flashed it is it ok when you stop or do you have to do it every time?

Very interesting, thanks for the explanation. I’ve got to jump the fields each time I start the bike, but I should mention that I’ve not ran the bike for long periods which, if I understand correctly, might not help the charging system function properly after not being used for so long.

I could try jumping the fields once and letting the bike run for a longer period, then trying again To check if the dynamo functions as expected.

The dynamo itself is opened up, checked and cleaned and functioned fine on the bench. That makes me think that the problem lays with the regulator.

[Idontwantapickle]

Rutgery-

Have you tried cleaning the contacts in the regulator?
You may have tried this but I didn't see it mentioned.

Hunter

[guzzisteve]

From my experience on Loops you don't mix Marelli & Bosch. Just a thought. I have seen bosch reg not work w/Marelli gen and visa-versa. One sys or the other not mixed.
Maybe prove me wrong, don't care all my sh*t works. I have seen wires come out of brushes on Marelli gen.
There is a ton of info in MGNOC Tips book #1, good luck

[moto-uno]

  Not too sure if this is relevant , but when HD used generators , the generator armature lead was fed battery voltage via the generator
indicator light circuit (when the ignition switch was turned on) . This light would extinguish after the gen output exceeded battery voltage .
Peter

[rutgery]

Rutgery-

Have you tried cleaning the contacts in the regulator?
You may have tried this but I didn't see it mentioned.

Hunter

Thanks for the advice Hunter. I've opened up the regulator to check the contacts and bench test it. I did look at the contacts and they seemed fine, but cleaning them most definitely won't hurt so I'll try it as well.

From my experience on Loops you don't mix Marelli & Bosch. Just a thought. I have seen bosch reg not work w/Marelli gen and visa-versa. One sys or the other not mixed.
Maybe prove me wrong, don't care all my sh*t works. I have seen wires come out of brushes on Marelli gen.
There is a ton of info in MGNOC Tips book #1, good luck

Good to know GuzziSteve, I'll not swap in the Bosch unit unless I have no other choice. I have another spare Marelli regulator that I'll try as well, but they acted the same with the bench check so I highly doubt it bringing better results.

  Not too sure if this is relevant , but when HD used generators , the generator armature lead was fed battery voltage via the generator
indicator light circuit (when the ignition switch was turned on) . This light would extinguish after the gen output exceeded battery voltage .
Peter

Same as Roy I don't know bikes of that vintage.

Charlie will probably be able to point you in the right direction

From your diagram and looking at a V700 diagram, I assume that's it equipped with a Dynamo

From Carl's diagram it looks like the Stator is flashed via the charge light, if that light is out that's why you need to manually flash it, as Roy said an LED is no use unless you also added in a resistor in parallel

I'd go over the connections and pay special attention to that charge light. It's odd that you need to flash it manually and then it all works, if the light is illuminating as it should and it's the correct wattage and not been modified then that should be doing the flashing for you.

However I'm not a Dynamo guy I know very little about them beyond the basic theory

Wait to see if older wiser heads prevail

John

I honestly do think you guys are onto something with the fields being flashed by the charge light, it would make a lot of sense. However, looking at the wiring diagram I don't see how this would work on the Marelli charging system, as no jumping wire is connected to the DF terminal. This would mean that the DF pinout is not connected to the field windings while F (As in DF) is usually a pinout for the field windings. Next to this the following picture is on thisoldtractor which indicates the pinout of the regulator being as wired up on the 700 right now:

[moto-uno]

  If your orignal wiring diagram is correct , do I not see a +ve lead coming from the armature lead ?  Peter

[Kiwi_Roy]

Heres another drawing that shows the generator light going to the armature, its just to tell you its working
The small lamp current would not have much influence on the armature
http://www.thisoldtractor.com/guzzi007/schematics/1967_V700_Police%20Series_1.gif
In my experience a generator will usually self excite, they have large hard pole pieces that retain a certain amount of residual magnetism.
I told the owner to measure the resistance between the armature terminal and the field terminal, at rest the regulator contacts should be closed, they open on over Voltage or Over current to add some resistance in series with the field.
Another way to excite a generator is to push in the cutout relay but you should only have to do that once.
Please measure the field winding to chassis, it should be somewhat similar to a Bosch.

[Antietam Classic Cycle]

http://thisoldtractor.com/moto_guzzi_loopframe_voltage_regulator_-_fitting_a_bosch_voltage_regulator_to_a_magneti_marelli_generator.html

[tetarabra]

Is the "frame" of the regulator correctly linked on the negative ?

[rutgery]

Thanks for all the thoughts and replies I'll check, clean and try the suggestions and will post here if/when I have some progress.

http://thisoldtractor.com/moto_guzzi_loopframe_voltage_regulator_-_fitting_a_bosch_voltage_regulator_to_a_magneti_marelli_generator.html

Thanks for the link Charlie! I'm really hoping I won't have to fit non original parts to the bike, but if I cannot get the marelli unit working, I'll do this. Is your V7 fitted with Bosch or marelli charging components?

[Antietam Classic Cycle]

Thanks for all the thoughts and replies I'll check, clean and try the suggestions and will post here if/when I have some progress.

Thanks for the link Charlie! I'm really hoping I won't have to fit non original parts to the bike, but if I cannot get the marelli unit working, I'll do this. Is your V7 fitted with Bosch or marelli charging components?

Originally it had Marelli, but I had bought a Scrambler Cycle alternator kit for an abandoned project, and ended up installing that during the V700's rebuild. My '69 Ambassador still has it's original Marelli generator paired with a Ford Falcon voltage regulator.

[Kiwi_Roy]

So the conversion sounds easy, take the wire currently connected to the field terminal and run that to the positive brush.
Take the wire currently connected to the square brush lug that was grounded and connect it to the field terminal (none of the field terminals connected to ground.
The Bosch regulator connects the field terminal to ground (chassis) completing the circuit.

[Don G]

Check the ground wire for the regulator!  DonG

[rutgery]

It's been a while but I wanted to finally update this thread. After checking the regulator and cleaning all internal points, checking the wiring of the bike again and again and finally running the bike for a while, it seemed the regulator did indeed need a first ''push'' to build up it's internal magnetism. So after jumping the regulator two times and letting the engine warm up, next starts resulted in a fully functioning charging system.

Thanks to all for the replies and inputs!

[jacksonracingcomau]

Well done, info on this thread handy for all

As another way to skin this cat, I wondered about late model belt driven Guzzi alternators, they sit in the vee, not sure if logical but perhaps they based this on old loopy drawings ?
So I got in touch with Pete Roper, he’s sending me one to test, will post results, all I really want is light, not actually chasing lights (or watts).

I know fitting small car alternators has been done forever but something about fitting new millennium Guzzi BB bits to the original design appeals to me , it might just fall in like it was made for the job !

[Antietam Classic Cycle]

Well done, info on this thread handy for all

As another way to skin this cat, I wondered about late model belt driven Guzzi alternators, they sit in the vee, not sure if logical but perhaps they based this on old loopy drawings ?
So I got in touch with Pete Roper, he’s sending me one to test, will post results, all I really want is light, not actually chasing lights (or watts).

I know fitting small car alternators has been done forever but something about fitting new millennium Guzzi BB bits to the original design appeals to me , it might just fall in like it was made for the job !

From the photos I've seen of the "Guzzi" alternator, it's not that much different than those used on the Field/Nolan or Scrambler Cycle alternator kits. I'm running the latter on my V700.

[jacksonracingcomau]

From the photos I've seen of the "Guzzi" alternator, it's not that much different than those used on the Field/Nolan or Scrambler Cycle alternator kits. I'm running the latter on my V700.

I’m sure there are many small automotive alternators, none likely to be much different, only to see how easily it fits really, carc BB is basically same crankcase.
Pete’s suggesting to use timing chest from that too, as mounts are prt of it, not sure yet, will offer it up
If I was getting really creative I’d fit up Bosch from early Tonti with alloy cover facing backwards, but bet someone has already done that. 
Yours neat and works for sure, not suggesting the carc one better, just different (and hopefully lighter)

[lazlokovacs]

martin, which alternator did you end up using in your bike? did the late model guzzi one work?

[jacksonracingcomau]

martin, which alternator did you end up using in your bike? did the late model guzzi one work?

Never actually got one to try so used orig marelli dynamo
Had huge fun freeing up brushes, seized solid in there, nothing the oxy couldn’t deal with but thought I might melt something , a lot of glowing red bits before brushes were liberated (totally unworn)
Cleaned reg points too, all tickety boo now, alternator on maybe list, I have no need for more leccy but getting rid of forth bridge bracketry would sit well with me.
Solid state regulator might come first if charging becomes an issue

[lazlokovacs]

yeah I've no need of extra juice either, was wondering if  I could get away without dealing with my broken generator bolt if I went to a lighter alternator and made a bracket that was also anchored to the dizzy mounting bolt...
might be more trouble than it's worth.

[Antietam Classic Cycle]

Might be some ideas for you here: https://www.thisoldtractor.com/moto_guzzi_loopframe_alternator_conversion.html

[Kiwi_Roy]

yeah I've no need of extra juice either, was wondering if  I could get away without dealing with my broken generator bolt if I went to a lighter alternator and made a bracket that was also anchored to the dizzy mounting bolt...
might be more trouble than it's worth.

When I put my loop back together I replaced both bolts with studs and it has the brace to the distributor bolt and still both studs were broken when I pulled it apart two years later.
I think part of the problem might be the engine casting to the bracket are not perfectly flat leading to it rocking aline the bolt line. I was thinking of trying to dish the casting slightly so it rests on the outer edges.
I still have to get the broken studs out.

[jacksonracingcomau]

yeah I've no need of extra juice either, was wondering if  I could get away without dealing with my broken generator bolt if I went to a lighter alternator and made a bracket that was also anchored to the dizzy mounting bolt...
might be more trouble than it's worth.

As posted above , suggestion was to use carc timing chest as well as alternator
This would negate the use of those bolts as alternator mounts to ears on timing chest, doing away with weight of bracket another bonus
But mounting that timing chest in loop frame would be much more work than getting your broken bolts out.

Charlie’s link to thisoldtractor shows one mounted similarly with home made bracket, this looks easy way to do it

[Kiwi_Roy]

Fixing old generators we would often find that the fields were shorted to ground, it could be that. Its not a big job to re-tape the field windings once you get the screws out.
We would use a linen tape then paint them with shellac, Glyptol would be even better, you will need an impact screwdriver to remove the screws in the pole pieces.
What type of bearings does the generator use, a ball race in each end or a ball race with a bush at the commutator end? (Gregs tutorial shows ball races at each end)
When you have it apart again examine it closely for signs of the armature rubbing on the poles
Please attach photos of the generator and the various components when its apart.
I can't say what the problem is but I can say its something simple.
Have you tried a different regulator yet as per the article from Greg Field? Here's an excellent tutorial he did on overhauling the generator note in the 4th picture in the nice even colour of the armature, any irregularities point to a bad armature winding. He used fibreglass tape for the fields, that's a bit extreme but should last for the next hundred years.
https://www.thisoldtractor.com/moto_guzzi_loopframe_generator_repair_-_magneti_marelli.html
Another place you can get a short to ground is where the long bolts pass by the interconnection between the two fields, its not easy to insulate the bolt but examine that area carefully.