there may be some plastic as part of the input socket on the speedo, but basically the speedo just has a square socket that the squared end of the cable fits into - if the end of the cable actually broke off the speedo would really be toast as those cables are quite strong .... pull the speedo and take the cover off, you might find an easy clean up job, complete disassembly for a total rebuild isn't really necessary, some carb cleaner and compressed air, then a dab of dry graphite might fix it up ... also pull the full length of the inner cable and clean it well, see if the end is still well squared and fits into the speedo socket ... and you can use a drill motor to drive the speedo to see if it's turning or seized, don't know about the AD years but some series require the drill running in reverse
Bill
