Small question please answer

The tranny, takes 650cc, which is 0.686847336 of a quart, a little less than 3/4 (.75) of a quart.

It says 650cc right by the fill plug on the side cover. Some oils even post ccs on the side. Make sure you dont use regular motor oil, as it can cause your clutch to slip. You need 2 stroke tranny oil. I like (and do many others) Bel Ray Gear Saver 80w, but your local atv/bike shop should know what you need if they work with 2 strokes at all.