So nice ! Essence of 2 stroke. By the time I started to actually ride I would be pumpin’ harder than the bike. That’s totally the way it should run. Load it up and clean it out. I used to hold my right hand with the fingerless glove over the silencer and blip the throttle, and feel/smell/watch it puff.
Once the engine is running the oil is getting thrown all over the place by the clutch basket so the level in the sight glass is bound to drop. In order to check the level the bike needs to be upright and the engine should not be running.