If its burning oil, best way to check... have someone start the bike up and you stand behind it looking at the exhaust, turn it on and give it some gas, if blue smoke comes out you're bike is indeed burning oil. To check if your head gasket is leaking head to your local pepboys or auto zone and buy leak glow. You mix it with the oil, put on googles that come with the kit and shine a light on your bike, you'll see a white|green or blue liquid depending what dye you get. Besides the res do you see any leaks anywhere? Under the bike after you park it or on the bike at all?
All this is just ADVICE because at the end of the day, you can do whatever the FUCK you wanna do.
Whore your slut out