The question that then pops up,,is... after rebuilding the engine,, how much oil should one add,,, compared to just draining the oil for normal maintenance???

Manual talks about 1 litre, and also the top level indicator inr the clutch housing...
I see the user manual talks about flushing gears with cleaner---- Somehow this must be drained...one can not expect every day user to tilt the whole bike???
I feel a bit stupid asking,, but after several years studying different manuals for vehicles I have restored...I find this among the most confusing... unless there is a hole i have not found letting the gear oil drain wtih engine is in level.
Svenn
Svenn