If your clutch seems to stick more than it used to, or doesn't seem to engage as smoothly as it did last year, you might want to look at the plunger on the master cylinder before you break open that clutch box.
Any squeaking or racket coming from the clutch handle can be an indication of a sticky master cylinder plunger.
To correct this you will need to look for the plunger on the clutch lever. Carefully lift the dust seal and spray some lithium grease or silicon spray lubricant on the plunger under the boot.
Try the lever a few times and repeat the process until all is smooth and quiet..