We found out about the grease when, back in 75, we had a 'Wing as a shop hack (45,000 miles in 3 years!) sliding joint only lasted 10,000 and Honda said no warantee cos it needed greasing EVERY service---shame it wasny in the service book! only other problem was when rear wheel bearings got play in them at 30,000 and wrecked the final drive---no teeth left and a lovely shade of gold on the overheated case!
Those two problems apart all we ever did was put a rear tyre on every 5,000 and service it!