The frame numbers are fairly simple, from memory so please forgive
anything I miss!
There were three factories plus the S works that produced F-
frames .The first was at Kirkby and these feature a K plus the year
ie. K65 on one side of the seat clamp and six digits on the other
side, the first two being the week number and the next four being
the frame produced that week. As these were made in batches and
perhaps not rotated stock wise this is a fairly rough guide only,
but the year should hopefully be correct!
Bradford built bikes usually have eight digits one one side of the
seat clamp..the first two being the year, the second two being the
week number and the last four… the frame produced that week..see it
really is simple!
“S” numbers are similar to Bradford, but stamped much cleaner and
straighter.
Oh and forgot the other factory at Nottingham but nobody understands
their system?
Ken B