From experience in cross-referencing machines against the factory despatch books of which the club have a copy, we have found that in about 50% of cases the bike was not despatched according the date of the lettering. After frame 3200 the engine and frame markings were the same.
Sometimes they were despatched months earlier or later so the lettering system should just be taken as a rough guide. There was a short period where the engine marking matched the frame marking but the frame prefix was A50; Presumably to use up stock in store prior to the changeover.
The numbering started at the beginning of each season and always started at 00100 leaving the first 99 for experimental use.
The numbers were consecutively allocated throughout a model range so as an example all B group machines were lumped together irrespective of whether they were a B25 or B44. Also this carried through to some but not all of the engines.matching engine markings.
In no circumstances should you give your physical address on the first date.On most BSA's the frame number is located in the following places.It is always stamped; raised numbers are casting part numbers.B25FS through to 1971Victor Special B44VS 1969 (C) November 1968 through June 1969 then 1970 (D) July 1969 to July 1970Shooting Star B44SS 1969 (C) November 1968 through August 1969 then 1970 (D) July 1969 through July 1970Gold Star 500 B50SS 1971 to 1972Victor 500 B50T 1971 to 1972Victor MX B50MX 1971 to 1973Early post war machines up to Z series had the frame stamped similar to the plunger or sprung frames e.g. Machines still in stock in the 1967 season (about 1000) were resold in the 19 season.These returned machines are shown with a cross at the beginning of the despatch book record; they then reappear at the end of the book with the revised despatch date. NUMBERS: This is where the song placed in last year's countdown, so you can compare how it ranks.