With a 1961 B40 having a grey speedo face, I am having a nightmare trying to find a replacement
magnetic head unit, can anyone recommend a replacement? not necessarily a genuine one but one
with a 2:1 ratio and 60mm diameter. Here's hoping.
Have you tried http://gaggs.co.uk. They were very helpful with mine
I met a chap at a Kempton Park auto jumble a year or so back who deals in second-hand motorcycle speedos - at the time, I managed to buy a BSA Dandy speedo off him which are very rare. I'm sure I've got his card or contact details somewhere and if I can find them I'll let you know how to get in contact.
I get my speedos / rev counters from here http://www.chronometrics.co.uk/html/speedometers.html . There not cheap but they are the best .