1967 Atlas primary chain case oil sealing

Well the engine and gearbox are rebuilt and hanging on the new engine plates and I am beginning to think about installing the inner primary chaincase,sprockets, alternator, and clutch. Two questions which I can't seem to find information on
1. How is the chain case sealed as the gear box mainshaft passed through?
2. Relative to the foot rest support I assume that the felt washer goes in-between the inner and outer case at the foot rest support?


Thanks all

Here's a picture of my mainshaft coming through the inner case. It's darn near a perfect fit. Here's another question how in the world does this fit allow for any primary chain adjustment?

For Question#1 - others have pondered this very question:
https://www.accessnorton.com/NortonCommando/how-to-make-the-atlas-dominator-primary-oil-tight.26860/

As you'll see in the pics, the hole in the actual primary inner case is oblong. There is a second part to it, which is two thin peices of sheet metal sandwiching the inner case and tacked together at the centre around the hole where the shaft comes through. This allows the piece that the actual shaft goes through to move forward and aft depending on the adjustment, while still providing some "splash" protection from outside and in.

Some good pics and explanation on another forum:

https://www.britbike.com/forums/ubbthreads.php/ubb/printthread/Board/3/main/91195/type/thread

As for Question #2, the second link shows a parts diagram for an older dynamo model chain case, but I don't believe they changed the location of the felt washer (Part #8) on later alternator models. That diagram shows an intresting "eyebrow" type overhang to keep oil away from the mainshaft hole that they abandoned on later models. (below for reference, and because posts with pictures are always more fun)

I'll add as an afterthought, is your inner case a reproduction or a cleaned up original?

Trevor Hallam said:

I'll add as an afterthought, is your inner case a reproduction or a cleaned up original?

Click to expand...

Thanks. very helpful. It's a cleaned up original that was powder coated. looks like I'll need to free up the discs you mention