regulator info

[artsmyth]

hello i am new to the forum iam restoreing 1966 monza 250 and needed help with rewireing the bike it has a 3 wire generator the part number on the regulator is 34.41.06 i would like to know what other guys have used to replace this part and where i could get one my engine number is 104326 and frame number is dm250*975997* any help would be great thanks

[JimF]

Is it the regulator you are trying to replace? The black brick that mounts on the frame under the front of the saddle?

I don't know of any replacements for it. It's only got two "active" components (semiconductors) inside: two diodes. The rest of it is just wire windings on a common iron core, and a high wattage resistor (passive components) Unfortunately the diodes are no longer being made so if one or both of yours has died it's not good.

Many diodes are of course available, bu the ones inside the regulator are in a metal can package, and they are pressed into a heat sink. Finding a diode that fits the heat sink is the problem.

There is also a fuse under a cover on the heat sink. If you think your regulator isn't working, you might check the fuse.

I also seem to recall that the charging light in the headlight bucket forms a feedback loop to the regulator, so that too may be required for the regulator to work.

Jim

[artsmyth]

the regulator iam trying to replace looks like their is 2 inputs from the 3 wire ac generator the wires are yello yello red the red goes to a temanal that goes no where inside the 2 yellos go inside and one out put regulated dc so with the grounded body their is only 3 termianls on the regulator

[JimF]

Could you post a picture? Your description isn't bringing to my mind anything I have seen before, but maybe with a photo I or someone else will recognize it.

Jim

[ducwiz]

Hi,

this regulator 34.41.06 is one for the widecase models. The picture shows it, and what circuit is inside.



https://www.ducatimeccanica.com/parti_di_ricambio/pages/partidiricambio0026.htm and https://www.ducatimeccanica.com/parti_di_ricambio/pages/partidiricambio0027.htm show regulator and alternator in the w/c parts list.

It is indeed meant to be used with a 3-wire alternator (2-phase system). If you find 2 x yellow and 1 x red wires coming from your crankcase and none of them has a connection to ground/engine case, you definitely have this alternator (6V-90W). It is not the standard equipment of a narrow case 250 from 1966, so your bike might be modified. If you find different colors and can measure a connection from either wire to ground, your regulator and alternator will not work together.

cheers Hans

EDIT:
http://www.motoscrubs.com/Ducati_6V_Regulator.htm shows the old "black brick" type, afaik the original one for a '66 Monza 250. The correspondent alternator has only 2 wires (also 2-phase system, but center wire grounded on the stator plate)
http://www.motoscrubs.com/Ducati_Electrics/Regulator.gif shows it's inner schematics and connections to the wire loom. (tnx JimF)