C15 engine numbers

[Stubaker58]

Hi all,
I'm looking to acquire a unit single project to keep me out of trouble(!), probably a C15. I've been reading through RR's three volumes and have got my head around what is what. I've even got a parts book and came across the bound service sheets in our local bookshop  for a very reasonable fiver.  However .... Is there any way of knowing the original spec of a particular engine and also which frame it was fitted to? The number of the project I'm looking at is simply C15 400xx.
I'm not yet a club member (I'm in the junior service, the Bantam Club!)
Many thanks

[chaz]

https://www.britbike.com/technical/bsa_serial_numbers.html

this will give you an idea, but to definately tie it down, it will probably be best to join and ask for a dating cert from the stock books.

it may be difficult to tie down as normally go by frame number. the engines were generally the same unit fitted to different models. the C15 variations only piston and cam along with gearbox ratio and sprocket may be different.
C15 and a 40thousand number without a suffix to the C15 would normally be a Star model. from 1962, 1963 being starting from C15 41807

a quick check would be to look at final drive sprocket.
40-3049 17 tooth  standard
40-3052  16 tooth  standard
40-3124  20 tooth trials
40-3072   15 tooth trials scrambles