These are most of the parts I think (except frame & forks), ready for re-assembly:

I decided to disassemble the (screw-on) freewheel so that I could clean the rear wheel and repack the bearings etc. (no need to remove it from hub). This isn’t advised normally; see the great information source of Sheldon Brown’s website which features this type of freewheel (ca 1980).

The photos below shows the freewheel’s locking plate removed (it’s reverse threaded), also outer bearings and shim/washer removed (left); with the sprocket assembly removed (right). There was some oil in the ratchet & pawl assembly, which was moving freely.

Dis-assembly of Sun Tours Freewheel

On re-assembly I packed grease in the inner and outer bearing races, and added a few drops of medium oil in the ratchet & pawl section; that’s worked for about 40 years. Some instructions on the internet say to put grease on the pawls, even to achieve a certain sound. I thought it more important that the freewheel works reliably, as some grease types can harden in time.

Re-assembly of Sun Tours Freewheel

Mega-Range Freewheel

On another (1990s) bike, I wanted to change the 6-speed freewheel to a “mega range” type with a lower bottom gear, but as expected the old freewheel was difficult to remove. I’ve read that some people clamp the release tool in a large vise, use a large spanner, or a smaller spanner with a pipe extension etc.. This was my solution using a tree felling lever extension to an adustable spanner (largest I have) …

Having fitted the new freewheel it took a while to get the gears working again properly, including fitting a slightly thinner chain (7.1mm) and adjusting the deraillieur position. I can’t engage the large (34 toothed) sprocket with the largest chainwheel, not a problem.