So if you have to add oil after a week or so I would say something is a miss. The normal for checking oil level is to it after running for a few minutes for proper circulation. Let sit for 1-2 minutes after shutting off then check level. Some people, & written on the dip sticks, say check on side stand. I prefer to k. mine standing straight up, that's the way the bike is going down the road. Have you looked for any leaks around the top end or oil dripping from the bottom of the air filter?
tourbox