[Randall-in-Mpls]

A 1980 Canadian import would be a Custom or Deluxe. I don't think they got the CX500A like Britain did.

 

[Randall-in-Mpls]

I think the PO actually had the rear cover off and used a standard screw/bolt to tighten the tensioner and then put the rear cover back on. At least that's how it looks.

So, camchain adjustment becomes an engine-out procedure. Brilliant!

 

[Randall-in-Mpls]

The "E" merely indicates that it's an engine number. Look for a plate riveted to the steering head or the frame serial number stamped into the steering head.