With the bike in gear and the engine off, pull in the clutch and see how much drag there is when you try to move the bike. If it hasn't been run in the last couple of hours, it's normal for the clutch to be sticky but it should break loose when you rock the bike back and forth a few times. If there is a lot of drag, the clutch isn't disengaging properly. Could be adjustment, might be a warped clutch disk or the wrong oil.
