I have a 83, which shares very few parts with the 82 or 84 models.
Some of the differences that I learned when we restored my 83 include:
1. The 82 clutch cover is ever so slightly different (but you can mode the pipe to make it all fit). On this point, the 81 cr clutch cover which is alloy can be adapted to fit the 83 with a bit of work. I did this on my one so I never have to worry about clutch rot!
2. Engine gears are mostly unique for the 83
3. Tank, plastics are different
4. Shock Is different
5. Head and barrel are slightly different
6. Pipe and muffler are different
I would guess that the frame is slightly different. I was lucky to find a good 83 frame and replaced the one I had.
All in all there are more differences than you would imagine. The 83 was really a one off, which was a pain because parts were very hard to find!
Not great when the gear box was fxxked and only one gear was usable!
P.s my cr is the one that gmc posted. I have tarted her up a bit since then with some nos plastic, ohlins shock, etc... It is a bloody good bike!
Cheers
ST