most companies dont give just one solid figure for the quantity of lube oil,, they just quote minimum and maximum range
e.g all chondas and honda 70 quotes the minimum range at 600ml and maximum at 800ml so u have the range ,, and all lubes for 70 are 700ml,,
reason for this is that after some use the oil level is reduced by small quantity to to many reasons as blow by whgere rings are weak or due to valves not making a proper fit with the valve seat thus allowing oil into combustion chamber to burn,, so if u put 800 ml and by the time u r about o change it the oil should have reduced to a usable limmit,,, thus minimising damage,,
hope u got the point,, for precise figures check ur bikes manual,,and i would recommend using maximum limit on bikes that have done much km's. for new a figure in between is ok..