I'm not making a big arguement for the cause here, it's just fun trying to read the minds of dead people,...
Totally agree, Richard, so let me add my 2p worth
:
During the last weeks I've been working on my Matchy basketcase and had a very close look at the yearly engine lubrication mods on the AMC twins (and there were many of them!)
Obviously oil starvation of the lhs cylinder was a big issue for them, as there had been several different attempts to get oil up there, even by having an oil route through a drilling in the cylinder spigot (to be omitted just half a year later due to massive over-oiling of the lhs pot). They ended up with a drilling through the inlet camshaft tunnel (behind the barrels) in order to have oil spill on the lhs flywheel, thus being flung up to the cylinder wall.
This led me to belive that the lhs conrod oil hole must be there for exactly that purpose, being on the lhs and facing the flywheel.
Mr. Hopwood also bothered to design a trough for the camshaft, which is shaped so that surplus oil will be flung towards the crankshaft, thus oiling the cylinders, so I suppose considerations on reducing the cylinder wall/piston sliding friction had been an issue with BSA as well.
As the return oil pump is of much greater capacity than the feed pump, I would say the sump IS dry. Have a look at the oil returning to the oil tank, you will see it is full of air bubbles for this very reason.
Sun is shining, so I'll go for a quick spin now and enjoy the results of Mr. Hopwood's efforts.
Cheers, Markus