Adjusting the tappets on my 83 R65 for the first time was interesting. The OT mark is at BDC. I took the plugs out and watched the pistons whilst moving the engine in gear using the back wheel.
Apparently the PO had a clutch problem in 1987 and BMW replaced it (and/or flywheel). I am sure they got it 180 degrees out, although my friend says it is is not possible when replacing the clutch(only) since there is a pin.
I set the tappets by watching for both valves closed at TDC on each side. This is fine, I can see the valves close, the piston at TDC and the clearances are as expected.
I haven't checked the ignition timing(impossible) and the bike feels fine. I guess it's been fine for a few decades

I have no reason to strip it down as she's running great. I would like to confirm the ignition timing though. Does anyone have a mm before TDC or other means of static (or dynamic W/O a timing mark) measurement means?