When these bikes warm up, the free play gap at the clutch lever can become larger, and that prevents good plate separation in the clutch. I readjust the free play once the engine warms up.
As Gary says, these clutches are not hard to operate. On mine, I even drilled another hole on the worm gear operating arm which is closer to the centre of the worm. That gives me more plate separation, but makes the clutch lever slightly more difficult to pull.