1950-1957 Excelsior

[1966 greeves challenger]

I am new to this forum and am greatly in need to identity a bike I picked up. Was told  it was a 57 excelsior roadmaster but I believe it to be earlier.  On the frame stem is
DS/ 624 on the engine barrel right side is B-7095, on left side CR9T with the R9 andT being upside. Case # are $55 on right and 7097 on left facing foward. Any and all help
Will be very much appreciated. Thank you

[R]

Not knowing anything about the later Excelsiors, an online search found only this,
said to be a 1955 R4 Roadmaster with 8E engine of 197cc.
The swingarm frame is listed  to have first appeared for 1954.
Look familiar ?  If not, we will probably need a pic of your bike to say much more.

[R]

It is not obvious that the Roadmaster went beyond 1956 ?

For more detail, it may be necessary to track down the book
Excelsior The Lost Pioneer by T J Liversidge.
Sorry for the convoluted link, click on it - google doesn't make it easy.
https://books.google.com.au/books/content?id=qxxwCQAAQBAJ&pg=PP1&img=1&zoom=3&hl=en&sig=ACfU3U02nZ9cu97BIPxiZB4Cb8pGtGUSkw&w

[33d6]

Your numbers don't read quite right. Excelsior did use DS as a frame number prefix at one time but the rest read like a mix of foundry casting numbers and something quite mysterious but possibly not quite right engine numbers.

As R says a couple of decent photos would be of help.

Cheers,