I know this topic has been talked about before and really it's an academic question anyway given we really don't know the exact sequence of sandcast production. From the earliest known casting of the sandcast cases to the final cases (excluding the french cases) we have about 5 to six months of production for the Sandcast. I was just looking at the distinctions listed in that grouping and noted that from our current estimates at best, 19 litre tanks and brass vent carbs were fitted to around 350 machines. By my reckoning estimates that, say, around 40 to 50 machines were produced each day. This makes the fitting of these tanks and carbs on about 2 weeks production.
When you think about this, it is quiet remarkable that they were able to correct this carb and tank issue within 2 weeks after commencing production. Obviously it is something we don't know but still; I wonder if they knew about the tank fouling the carbs issue before production began but didn't have the issue sorted or they found the problem issue after production began. I would have thought the early testing would have picked this issue up but we'll probably never know the answer
If one reads the distinction list and takes into account the known changes as listed in the parts manual there are changes that occurred after the first 100 engines were produced
When you think about it these changes throughout production were quiet an achievement