Ok, yes I have the same silencer, and remember it was a pain to get the bracket off!
The kickstarter, yes always use it, when it starts slipping the clutch plates are going! they get thin, so the kickstarter slips, strangely the bike runs OK with them, and does not slip, I rode it a year or so, but then it got too bad, I changed the plates, and is perfect now. Changing the plates needs a special tool, that can be made, have all this info somewhere, but there is a big spring clip that holds it all together, taking apart is easy (use eye protection!!), but assembling, you have to compress the springs!!
You can do all this with the engine in the frame, only need to remove the cover, what oil/grease are you using? the original (Ambroleum) is very difficult to obtain nowadays, I use OO-grease (double O) you can buy it anywhere.
To shut off the engine, you need the right switch on the handlebars, there is the hi-lo beam, and on top the engine cut out, just a wire to the points, that connects to earth on the bars, and engine stops.
This switch is not 100% original, but works for me;
Will see if I have the info on the computer on the clutch, I do have the big 1942 army Maintenance manual, but not scanned (yet) more proof they were used by the army!
Cheers,
Lex