Proper swingarm setup

The bushes have outer and inner steel sleeves, separated by rubber.  The outer sleeves are pressed into the swing arm.  The inner sleeves project just enough to bear against the inside faces of the frame lugs.  A spacer tube goes between them to give the correct width. When the rod goes through, the nuts at each end are tightened hard against washers against the frame lugs.  This grips the inner bushes hard so they do not turn.  The swing arm movement all takes place within the rubber.  It's advised to put weight on the saddle before tightening the nuts so the rubber is in neutral position when on a smooth road.
There are stories that outer bush sizes were changed.  But if yours will press in, they are probably correct.  Wrong ones will be obviously wrong.
Once in for a few years they are virtually impossible to remove without brutal force.  But they seem to last forever.

Hi Tim
I had to change my rubber bushes quite a few years ago, but only because I didn't remove them prior to having powder coating done! And it destroyed the rubber. I found the best way to remove and replace them was using a press, it was more controlled to enable the same distance to protrude at each side. I had to fit some spring steel to 'shim' them as they were about 002 thou slack. 
Someone once told me ( it could have been the late great Mick Hemings, but couldn't be positive) than Norton used Land Rover spring hanger bushes fitted to the end of the springs  for the swinging arm bushes! They are  similar, so it could be true.
Good look, it is not such a difficult job, also I think the wide line and slimline are the same width, and when fitted only just fits between the frame flange, in fact you may even have to ' spread' the frame a little bit to help installation, the finished width should be the same width as the top engine plate tube. 

Regards John O

Ps you are correct Tim they do project a little from the swinging arm, but to ensure they are the correct width I assembled them with the spacer, on the swinging arm bolt and checked the total width was near before inserting in to  the swinging arm.

I agree with all of the above responses. I can only add that when the swing arm is presented to the frame it must be exact as it is a very neat fit. As for spreading the frame good luck with that.

Remember the spacer is between the inner bushes so it needs flanges to centre it in the tune.  Possible on lathe but not exactly simple.   Andover Norton part 06/7716