Thanks for the plug Stephen!
Quite right. Monosoupape (sic) means literally, one valve.
The induction of the fuel air mix happened through the crank case and up either through a valve in the piston (on the earlier versions) or recesses in the bore such as you would see in a two stroke engine.
The Valve at the top of the cylinder is the exhaust.
I have a cutaway some where... hang on...
I have no idea where I picked this up from, so if I am treading on anybody elses copywrite, I apologize.
The magneto and spark plug lines are maybe what you are looking to add Mark.
Cheers,
Hugh