conferrmation required

[classic48]

Hi All,
      Wife purchased this BSA Bantam and was told it was a 1952 matching number bike.Here are some of it's details.
  BD3B Top of engine LHS near carby, YDIS 59657 on the front of
  6758
               the frame LHS , Type S55/MK8
                                     Spec. no   1130
                                    Serial no   20977
                   Cheers   Classic 48  :-/ :-?

[L.A.B.]

Hi All,
      Wife purchased this BSA Bantam and was told it was a 1952 matching number bike.Here are some of it's details.
  BD3B Top of engine LHS near carby, YDIS 59657 on the front of
  6758
               the frame LHS , Type S55/MK8
                                     Spec. no   1130
                                    Serial no   20977

I think your text has got a bit jumbled?

So as I understand it,
The engine number is BD3B 6758 = 'B'antam 'D3' 'B'attery electrics and the serial number appears to be from the 1955 production year (starting from BD3B 5138).

So the engine (or at least part of it?) is from a 153cc a D3 model?

Frame number: YDIS 59657  Appears to be from 1951 (from serial 40001) as 1952 production started at 64001.
  
http://bsaownersclub.co.uk/Images/Year_Listing/09.jpg


Type S55/MK8
Spec. no   1130
Serial no   20977

Wi-Pac Generator?

http://www.freewebs.com/bsarestoration/wipacs55mk8gen.htm