So we are back to restoring my 1965 AZ. .
Now we are considering replacing the 6-volt system for a 12-volt one.
Reasons enough if you don't live in western Europe , but that's another story!
Lights, fuel gauge and fuel float , coil etc., etc., etc. , we know that , but the problem seems to be the alternator, direct current alternator, or whatever you want to call it.
This is behind the fan on the crankshaft and can't be replaced by a 12-volt alternator with a pulley and belt.
Does anyone have experience with this, and how was it solved? Is it possible to solve this by using a different voltage regulator?
Any suggestions are welcome .

Put an alternator from "modern" 2CV, just under right side cylinder. Take old 6v dynamo out, put fan from 2CV4 or weld the pulley from 2CV4 to old metal fan. Make room to wing for alternator, and of course some sheet metal to protect from water/mud/snow from front wheel...

There was good photos about that, on snail -forum, but that has gone some time ago...

Or, make another solution what I have been thinking about. Take permanent magnet alternator from Harley-Davidson, install rotor to original dynamo rotor with removed coils etc, and put the stator like the old dynamo was. With H-D voltage regulator, it is easy to connect, only wires from stator to regulator, and wires from regulator to battery, no need any other wiring needed. Ok, cost some money but not bloody expensive, nothing can be seen compared to original dynamo without removing the fan...

I might choose the first solution, need only 2CV parts and some metal to mount alternator, very cheap...

The Harley Davidson solution is very interesting.
A bit more expensive, but nice.
The only question remains : Will it fit ?

Will it fit? Not directly, but with lathe and some other machinery it will. If I had old 2CV, I am quite sure to make it fit...

The alternator is narrower than 2CV dynamo, and has larger diameter but not much. Mountings is what is needed to fabricate, for both stator and rotor...

Yes, you are right.
My son and i looked ito it and we can make it fit.
A friend has a lathe and other machinery for metal we can use ,and my son is able to make the essential parts so it will fit .
As soon as we are at that point , i will put some pictures and description on the forum,. maybe it is of any use to someone else .
Any way, thank you so much for the tip, we did not think
of this solution ourselves before.

An other system i have seen on an old Finish 2cv. They put an alternator transversal on the gearbox with a belt over one brake drum.

^Yes, have seen that solution. Almost too easy to make with old enough brake drum, what has fins on them, the belt has perfect fit to those fins...