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#843705 03/21/21 4:56 pm
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My late 1952 model year ZB34 GS crankcases are dated stamped 2 11 51. I am assuming that is 2 Nov 51. Would that be the date the cases were machined?

Shaun in another thread lists 1 4 55 date for his 1957 DBD. How long did cases sit around before being built as a complete engine?

Gordo


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My DB34 cases are stamped: 10 55

The performance test was done 12 12 55

The bike was dispatched to Hap Alzina on March 5, 1956


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my DB500 is dated 1 4 55 . albeit upside down . It to went to Hap Alzina .

Last edited by ducati2242; 03/21/21 10:01 pm.
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Thanks for the inputs. My ZB dated 2 11 51 went to Dublin in May of 52. So it seems the engines normally moved along within months of the stamped date.

Gordo


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BSA assembled bikes in batches usually to order but casting & forgings were done as a continious run till the moulds needed servicing
The parts got stored in stillages till needed for machining so could have in theory been sitting around for years .
If you look at any of the period movies or sets of factory stills, in the background are stillages full of partially finished parts.
While not as efficient as Just in Time used today, it was overall very cheap.
If the furnace held 5 tons then you made 5 tons of castings weather you needed them this week or not.
I am not sure but it is most likely the date would be the maching date, assembly date or inspection & passing date rather the casting date as they would have been casting for several weeks till there were enough castings for the tool setters to set up the mills & lathes to machine the cases.
When this was done they were all measured and stamped according to the gauges that fitted.
They are the funny litle letters, numbers or just weird stams you find all over the place usually in locations that are out of view on an assembled machine.
Weather the comp shop machined their own gearbox cases or not is unknown to me but I would doubt it.More likely they got a pallet of "A" gauge box cases then built up the various competition clusters into them.

Last edited by BSA_WM20; 03/25/21 10:04 am.

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I would say the "machining date" would be the correct answer to the question. I've encountered many instances of the date stamp inside the timing chest behind the idler gear. This has been observed in BB to DBD cases. It seems illogical that there would be a partial teardown to stamp the cases

On the other hand, the five Semi-unit A10 cases I've inspected, all had different date stamps. This leads me to think that the mismatched dated case halves were bolted up and line bored prior to the crank assembly.


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Originally Posted by BritTwit
I've encountered many instances of the date stamp inside the timing chest behind the idler gear. This has been observed in BB to DBD cases.
My '53 BB34GS is date stamped inside the timing chest.

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Consider the date stamp could have been the machining date, or even the inspection date & not the actual manufacture date


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