This is not as easy as it sounds.
It’s no doubt easier however when you have the bike broken down. Many others have meticulously documented their approach to cleaning various components (Brooks Airhead Garage is one of the best and a lot of what worked for me was lifted from his website).
Getting off the general grime of 36 years is the first problem, and for me this involved various degreasers, lots of WD-40, high pressure water and lots of rags.
Frame:
The frame was degreased and dried and then stripped back to bare metal. I used a stripping disc on an angle grinder for this. Then I cleaned with acetone and applied Rustoleum etch primer and semi-gloss enamel. Many coats.
Swing Arm:
The swing harm got a similar treatment to the frame. The final drive cover was cleaned up with red scotchbrite and WD-40. In one of the photos below you can see where I have cleaned the top half of the final drive cover but not the bottom half.
Aluminium:
The aluminium surfaces (engine block, gearbox, final drive, fork sliders) all develop a deep patina over many years. However they can be cleaned up, and if you are patient and meticulous, they can be restored to as new condition. I used Autosol Aluminium cleaner and also a lot of WD-40. I also used red scotch-brite and a similar material on the Dremel for difficult to reach places.
Engine covers:
After cleaning these I painted them in high temp enamel.
Baked on coke on pistons:
I cleaned these with a scotchbrite- like Dremel attachment. They came up pretty good.
Cylinder Heads and Barrels:
I had these vapour blasted by a local shop- they came up pretty good! I couldn’t face the idea of trying to clean and polish the fins individually.