Yes my piston is numbered 1803 under the shell, and a similar piston will surely work.
by a web search and usin the table of my previous message it is an Asso 2845 (shell 1803), also the fact that on the inlet side it is shorter corresponds :
so i am pretty shure now that , if i want to replace mine i have to find an ASSO-Werke 2845 with shell number 1803.
my question is: what minarelli code, which tipically is 7 dicit (ex. 710XXXX ) corresponds to it?
<--that's the question! :rolleyes: :quoi:. , can anybody with a minarelli catalog help me?
and if possible identify also the minarelli code for the segments only? (example 7108XX-X)
to Gitane-Mais question:
No, unfortunately i am afraid not a corsa corta ,because..I have measured the excursion, it is 42mm,and this corresponds to a standard 38.8x42 standard 49.9 cc Minarelli. I have not opened the block to see the mechanics and measure them, just removed the termic group after measure it's excursion with a caliber, from top of the PMS (top position of piston to PMI (lowest point of piston), and anyway my block has no oil chamber micro vent.it is a P6 standard as far as it seems then, the only particular thing i found is the "biella" (sorry italian word , don't know the english word) has 3 small holes on the top connection, for lubrification, bright copper colour.
i am wondering if in origin my motorbike was sold by KRAM-IT with a corsa corta just as in the picture i have found on the internet, maybe some expert of KRAM-IT can help understand better these series and their history.
I will take more pictures this weekend, for the moment i can attach another picture of the codes on the carter:

and some others of the Kramit MKS 50 er:
here follow the M.C.S Minarelli patented system:
and here follows the inner cylinder and details of the inlets of the Minarelli 54 Radiale Competizione 'Gilardoni 3' serie:
