Silly question, but is the bike on its centrestand or on the side stand?
The manufacturer gives you the capacity for full, but the actual volume that a reservoir will take depends on how much fluid is still in there or how level the bike is. The same goes for engine oil for a car or four stroke bike. Check the dipstick as you approach full. It's not necessarily the whole jug that goes in.
The final drive gear case should be filled to the level of the filler hole. Above that is overfilling.
