Master cylinder for c8a

[serge]

Hello

Some years ago I had start the rebuilding of an HUP (coming from the museum in DIEPPE). I stoped the work because I was not enable to find a master cylinder. Recently one of my friend found a new master cylinder whose external sizes seem the same as the original part.

After the dismounting of the part ,I saw that the bore was 25 mm and not 1'1/4
so my question is about the efficience of such part. These one has been builded in ARGENTINA.

Thanks for any comments