Re: which motor oil do you use?
OK, here's the "general consensus", and the entire oil thread, in a nutshell.
Use any oil you want. Regular, semi syn, full syn, cheap, expensive, whatever makes you sleep better at night. EXCEPT oils that are marked as energy conserving (EC) or "high mileage" oils. Those contain special friction modifiers that will make your clutch slip. Otherwise, go nuts. There is very little to zero concrete evidence about which oil/brand is "best". All oils pass API standards, I don't remember what the Max motor specifies as minimum but I do know it's been succeeded at least once....meaning any oil you're likely to find meets a standard better than the Max "technically" needs.
Some people here religiously change every couple thousand with only the most expensive oil you can buy. Their bikes work fine. Others, like me, change it whenever, using whatever oil happens to be on sale. My bike also, works fine. My general guideline is when neutral starts getting tough to find, it's time for an oil change since the clutch is dragging more from the oil being less slippery. Usually 7-8k miles.
I've seen a generator motor run with used deep fryer oil in the case for days with no ill effects. Any oil is better than none.
Back on topic.....
Assuming you changed the filter, add three quarts then start the motor. Run it for a few seconds. Put it on the centerstand and wait a minute or two. Then top-up to the upper line on the sight glass.