I would check the thickness of the brake rotors, minimum thickness is .180 in., remember, that is the high part of the surface, with normal use, the OEM rotors develop deep grooves .
I installed EBC steel rotors on my '81 R65, along with EBC graphite pads, didn't notice any real improvement with dry braking, but wet braking was dramatically increased .
If the transmission has not gotten a lot of water in it, from the speedometer drive boot, I would just check the magnetic drain plug when transmission lube is changed .
I was getting water into the transmission for a few years, until I figured out how it was getting in, this was in the mid '80's, before the internet was widely available to the average person .
I was getting a low vibration from the transmission, I started getting a lot more metal on the drain plug magnet, has the transmission overhauled, the bearings were quite worn .
If you still have BOGE shocks, replace them, they weren't very good shocks when they were new .
I would check the length of the brushes on the alternator, mine were worn out at around 55,000 miles, the 'GEN' light was glowing dimly .
I've removed the starters from both of my street worthy R65's, cleaned and lubricated them, there was not any evidence of any lubricant left anywhere in the starters when I disassembled them .
If you still have OEM rubber brake line(s), I would replace them with braided stainless lines, the price of the stainless lines is around what OEM lines would cost .
Steering head and wheel bearing cleaning and lubing, or replacement if necessary, may save you problems in the future .