1928-31 Indian Scout primary cover set.
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Primary cover - or Gear Case - set for 1928-31 Scout.

Other side.

Seen from the top with four-bolt opening for generator drive. , good looking threads for the oil filler cap and one of the dowels that keep inner and outer aligned

Inner cover also looks good on the inside. Both dowels are there, as well as the intermediate gear shaft.

So does the outer cover. Clutch worm and bushing for intermediate gear shaft.

28D1 for 1928-on. The "108" is also stamped in the inner cover; I wonder if it is in both to keep them together as a set while being made at the factory?
I am not sure I have seen this with Indians before, but have recently seen it on an early 1950s Triumph primary cover set, and it makes good sense with parts that are designed to be in alignment (the intermediate gear shaft bores most of all).
There doesn't seem to be similar stamps on the 1920-27 cover set, but maybe they will come out with cleaning.
Or maybe I am wrong about these stamps. On reflection, I am probably wrong. I remembered that the inner cover here was also stamped "108". So what does it mean?

"108" stamped on 101 inner cover.