I fit the thin backing plate first with the long edge down, then the cam chain tensioner, and at last the thick backing plate with long edge up.
But i dont think that this is the correct way.
Hi Les, seems that my way is right.It is the correct way.
http://www.classicbike.biz/Norton/Repair/70up_Commando/70upCommando.pdf
Section C30,7.