1920-27 Indian Scout primary cover set.
Click for bigger pictures.

Primary cover - or Transmission Gear Driver Case - set for 1920-27 Scout.

Other side.

Seen from the top with B21540 oil filler cap (which got a new number in 1931 but was otherwise unchanged, as far as I can see: 35B494, and yet another number later without obvious changes; 661003) and opening for generator drive.

Inner cover also looks good on the inside.

So does the outer cover.

Nicely patinated original 20B50 Clutch Release Worm Dust Cap :-)
This cap was on all models from 1920 to the last Chiefs in 1953.

Here is a new 20B50 for comparison + the modern o-ring seal that replaces the original felt seal.
More clutch parts here - and I am probably going to try making a page with all the clutch parts at some point, but there is only me to do everything here, so it may be a while.