I am wondering how to disassemble the right side of the transmission. In particular how is the cover of the kickstarter spring mounted?

The steel spring cover is simply pressed on to the kickstart boss but can be very tight. It's quite difficult to find decent replacements so care is needed.

It's certainly worth soaking well in penetrating fluid. It's not easy to start them off from behind. A hose type clamp tightened around the cover and then tapped round with a soft hammer is often the best way to get them moving.

Thanks for the info.
I realised that it is not necessary to work on the cover if you want to change the gasket of the gearcase cover.