Daytona,
I drain the 2 bolts and replace the filter. Thus far I have done 2 oil changes and both times the oil level was above the sight glass. Last time I used a gallon of shell 15-40 and poured in exactly 3 liters since the gallon had marking for liters. This time I had qt bottles of castrol 10-40. so I poured in 3 bottles and called it a day. Again the sight glass was all filled up!
Both times I let the oil drain over a lazy Sunday brunch, so it drained a while. I didn't warm up the engine either time. Just pulled on the center stand and drained the oil.
That's all I did.
The sight glass is very reliable. Are you draining your oil by removing the TWO drain plugs or just the one drain plug?
You dont NEED the 2 stroke oil if you dont let it sit long but it cannot hurt to do it anyway. Long is about 1 to two weeks.