Primary case

I use Loctite 515 for the sealer, no paper gasket at all. I also applied it to the area noted in the pic below to help keep oil in (as much as one can on a 40's Indian at least).

 Primary case inner and outer carefully prepared. De-burred and cleaned back to shiny metal.I use Scotch Brite to get the surfaces nicely clean. I apply 515 to both surfaces, then clean off surplus with a rag.

 Drain plug sealed with Loctite 567. This is an excellent thread sealant, much like a liquid thread tape.

 Loctite 567 on the chain adjuster..