Do you have the correct cork washer and spacer tube fitted to the footrest splined carrier?(behind the inner cover)..If these are incorrect (too short in the case of the tube, too thin in the case of the cork washer) the inner cover will be forced inwards when the footrests are tightened up...
Also, what make of chain do you have fitted?...Some Japanese chains are wider for a given size than European chains such as Regina and the space available is limited even when set up correctly...Ian
Thanks Ian for your reply. I use Regina chain, I use two cork washers for the inside tube spacer (one at each side) between the inner primary case the outside cover. Behind the inner primary case I use only a tube spacer and not any cork washers
I usually fit the inner cork washer behind the inner cover at the outer end of the first tube..That seals the cover from behind. I fit the other washer at the outer end of the tube that is inside the cases to seal that side.
To test the set up you have, slacken the footrest bolt completely so the cases don't have any pressure exerted on them. Remove the footrest as well if necessary to achieve this...Then reach behind the cover and test to see whether the inner spacer tube has any free movement axially, it shouldn't...You can just get to it by hand from underneath but you may perhaps need to use a long screwdriver or similar...
I believe the assembly drawing found in some BSA manuals is incorrect....Ian