This shows how I remove the inner timing cover, timing chain, crankshaft timing sprocket and nose bearing. You can read all the details about how I do this work here: brook.reams.me...
Have a old 1980 R80 and have had it since 1988. Got it cheap due to it ran like shit and clanked badly. Turns out that the timing chain was so worn that I could rotate the crankshaft 5 degree before the cam started to rotate. Previous owner ran the crap out of it for about 130k miles so pulled the engine down all the way to check for other problems, strangely enough everything else was in specs, but did put in new mains/rod bearings anyway. Contemplated changing out to old double row timing chain setup, yep it can be crossdecked, for better life but I considered the first owner and how he beat the hell out of it and it lasted 130k miles so it wasn't a real issue. Since you have a 83 you most likely have the lighter flywheel, a holdover from the BMW days of pulling sidehacks the older units had a 20lb flywheel, mine still has that flywheel, they can be lightened to around 9lbs without issue. A bunch of us old air-head guys play with them and some have installed lightened flywheels, it really wakes them up on pep and shifting is somewhat smoother.
Thomas, I lightened the flywheel on my 1975 R75/6 when I road raced it. It helped when shifting at high RPM as with the stock flywheel I would get enough momentum transfer to lift the front suspension which was not good when in a corner.