Draining oil

Hi Fellas
Had the bike on the centre stand and notice a lack of oil through the window. Anyway to shorten the story I drained the oil on a luke warm engine. I just didnt want to get her to temp in case she was low on oil and I wanted to minimize any damage I may have been doing. Took the plug out and I measured approx 2litres of oil. Should I put some new oil through her and restart the process and get her to temp and drain again or no biggie??:silly:
Another question is that I just changed the rear tire and after putting it back together notice that the rear sprocket has a little slack in it. Not the sprocket alone but the whole hub. I'm only talking minor slack of a few millimeters but thought it would be all tight??
Cheers Oz

I would change the oil and filter, and keep a close eye on the oil consumption.
slack in the hub, there is a rubber "cush" drive insert in the wheel you might check it to see if it is worn or hard

"A little slack" is normal for the rear sproket hub.
Alot of slack may be a different story.
Pull the sproket hub off. It will just pull out if you have the wheel off.
Then check the condition of the rubber cush drive. If it's in pieces or looks damaged, you may want to get another.
The 650's rubber cush drive is one piece, where all the large parts are attached with thin connections.
I believe other models may have separate pieces (5 or 6) that make up the cush drive.
Some have built up a worn cush drive using an inner tube or some liquid rubber goop.