Primary chaincase screw sizes

[Mosin]

Quick question: I am aware that two different diameters of machine screw are used to hold the primary case to the inner. The majority are smaller diameter of various lengths, but there are also three larger ones towards the front of the bike which go right through the primary inner and screw into the actual crankcase itself. Does anyone happen to know the size/dimensions of these three larger screws?

Thanks

[muskrat]

G'day Mosin.
42-7517 is 5/16 x 1-15/16 whitworth but I'd double check the length as if too long it will foul the crankshaft web.
Cheers

[Mosin]

Just the information I Was needing. Many thanks!

[Colsbeeza]

Hello Mosin,
Roger SB did a great job on this some time ago.

Check out  -  https://www.a7a10.net/forum/index.php?topic=13099.45

I have attached Rogers sketch, which shows lengths. I went through this a few months ago, and found Rogers sketch was spot-on.
Cheers
Colin

[a]

https://mikesclassiccyclespares.com/product/42-7517/
These are genuine BSA NOS ones if you'd like??