Stamping on rear swinging arm ?

[asterysk_usa]

Does this stamping have any use in terms of identification ? It's in the bottom of the lower swinging arm and now visible because of the grit blasting


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[RL]

I'm no expert but I would suggest that this is a part casting number as all identification numbers are taken from the actual frame number. The year model number changed in August so it is possibly to have a 1954 frame number and 1955 engine number.

[SPRIDDLER]

Casting numbers were raised rather than stamped, but after any finishing/machining of the raw casting another number was often stamped into the finished part or sub-assembly.
Your number looks to be 021022. The part number for the finished '55 rear fork is 021543 if that's of any relevance

[asterysk_usa]

I hadn't thought about it being a part number, so searched through the parts database spreadsheet and nearest I could find was part 021023 (as opposed to the 021022 on my arm) and that was for a 1954

At some point I will know which of my parts are from 1954 and which are 1955 !!

[SPRIDDLER]

When you get your Dating certificate it might help to determine the year of manufacture (not first registration) your bike.
As previously mentioned, bikes made up to August 31st 1954 (before the factory shutdown and London show) were 1954 models. Bikes made after Sept 1st (after the factory annual shutdown) were 1955 models. I believe the '55 is known as an 'interim' model as it was rather a mix of parts for that year only.

[ajscomboman]

For some strange reason the actual part number in the spares book is always one digit more than the number stamped or cast in the part. I've found this to be the case with all part numbers stamped or cast on twin and singles. So finding the part in your list is 1 out is the norm.

[asterysk_usa]

For some strange reason the actual part number in the spares book is always one digit more than the number stamped or cast in the part. I've found this to be the case with all part numbers stamped or cast on twin and singles. So finding the part in your list is 1 out is the norm.

Aha , that's good to know. Also means I now know my rear fork is a 1954


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[Group Leader]

For some strange reason the actual part number in the spares book is always one digit more than the number stamped or cast in the part.

Well how bizarre is that! I wonder if I'll be able to remember that little nugget?

Alan

[asterysk_usa]

For some strange reason the actual part number in the spares book is always one digit more than the number stamped or cast in the part. I've found this to be the case with all part numbers stamped or cast on twin and singles. So finding the part in your list is 1 out is the norm.

It might be worth putting this info into the FAQ or a sticky, I think it could be hugely valuable . Might also be worth putting somewhere on the club spares website.