Primary case lack of drain plug

[stevejs]

I've got a 1954 swingarm SS. It doesn't appear to have a drain plug (or level plug) for the chaincase. Could it be that someone's fitted an inner case from something else? Were perhaps the singles or earlier A7's interchangeable?

[bsa-bill]

drain plugs for the primary case where a later addition, you drain the case by removing the third from the front bottom case screw ( I think it's the third ), the top of the hole for the screw in the inner case should be open allowing oil to run out.
  if your saying this doesn't work on yours then maybe the inner case has been changed but would be easy to alter I would think

[stevejs]

OK thanks for that. I thought maybe the drain plug was a later addition, but all the tech documents I've read so far, just mention the drain plug for emptying the case. I'll check out the third stud along...

[duTch]

 Yep, I  think the  drain plug came along after about '58- my '58 RR didn't have of.
 But I think the cutaway in the screw boss is that Bill means is the level one.
 The actual drain hole plug I would expect should be at the bottomest one (where most of the oil is    )   
 

[bsa-bill]

But I think the cutaway in the screw boss is that Bill means is the level one.

Well spotted Dutch, yes I was thinking of the level one right enough

[stevejs]

Thanks chaps. Another little problem sorted courtesy of this excellent resource. Pre-internet, getting an answer to such a simple query could have involved a fair bit of hassle.