Lucas guy with Marelli question :)

[Turboguzzi]

Yes, Lucas as in lord of darkness... 

Well, im trying to help my friend with his Astore dynamo which is not charging.

I have lots of experience with vintage lucas dynamos that had the regulator outside the dynamo.

All you had to do to get a good snapshot of dynamo health was to shorten the two exit posts, connect the two outputs, F & D (field and dynamo) with a piece of wire, start the engine and measure voltage between F/D to body.

in the Marelli dynamo with the built in regulator, this wont work of course... so do you all disconnect the regulator internally when you just want to check dynamo health? 

Who do you understand if culprit is dynamo itself or regulator? 

your inputs are welcome! 

[John O Regan]

Hi,

Have you  taken the cover off to look at the brushes and the commutator 

A good cleaning may get it going

If you have the dynamo removed connect a positive to the 51 connection and the body to negative

now push closed the cutout contact and the dynamo should motor smoothly

I think they are like Bosch dynamo's in that one end of the field coil is permanently positive and the cut out earths the other end.

On My GTW the cut out stuck closed and burned out the dynamo and regulator in spite of having a 10  amp fuse on the battery!!!

I replaced it with a Lucas E3L and DVR2 regulator, I made an adaptor to fit the marelli end cover onto the Lucas so it does not look out of place. 

As I had a spare Lucas dynamo it only cost me the price of the reg and a new battery (because the one previously fitted 

buckled the case)

The Lucas dynamo is the same diameter and taper as the marelli.

Loctite or wire the pinion nut, they are known to fall off

John

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[RICHARD YAMANE]

I would give the brushes and commutator a look first. 
50 years ago I used to know by heart all the drills to full field and test generators but now I’m just a blank stare. 😄

Rick Yamane
Importer of Vape/Powerdynamo ignition systems and Polisher of bikes at Motion Pro

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[Turboguzzi]

hi guys, tnxs

Augusto came again today with the Astore, 

brushes fine, commutators clean, "by-passed" the regulator and still almost nothing (0.1 V at mid revs )  so  at this point, with dynamo installed and difficult access to the wires, gut feeling is he needs a new one or find someone to rewind his. 

would remove the dynamo for a proper check, but this is so much more complex than with a british Lucas magdyno and i have no room in my garage to keep his bike. 

sounds funny that i should ask here, but if anyone is aware of a dynamo specialist in italy, let me know. most of the online resources i had in italian are no longer active and so many old places have shut down

[RICHARD YAMANE]

Sounds like it is likely the armature then. If you have a local auto electric shop or small airport you might be able to locate someone with a growler to test it. The magnets should be checked too. They do lose magnetism over time. In any case you will need to have the unit off the bike. If your friend cannot do the R&R work, he'll need to take it to someone who can and has space to store the bike while the work is done. The shop doing the generator rebuild work is the likely place.

Rick Yamane
Importer of Vape/Powerdynamo ignition systems and Polisher of bikes at Motion Pro

To view this discussion visit https://groups.google.com/d/msgid/guzzi-singles/a641d808-c8d4-4f6b-bebe-87816f3920a8n%40googlegroups.com.

[John O Regan]

Hi,

Did you try closing the cut out contacts on the regulator with the engine running and battery connected? this will re energise the field coil magnetism that it loses over time

John

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