Tom, I would be very cautious prior to purchasing an after-market speedo for your R65. Any off-brand gauge must match the gearbox ratios for each gear.
Acewell produces an electronic instrument that is a single pod but provides more data than you'll ever need: speed, tach, odo, trip, etc. Also, there is an Acewell accessory cable that plugs directly into the gearbox just as does the OEM cable.
I have a Trail Tech digi Vapor on my '81 R65 and '78 R100S. An Acewell is mounted on the '83 R65.