The Cb500's clutch mechanism is different in many ways from the 550's.
The Cb550 has an "over-center" actuator in the clutch cover. If you do the adjustment at the case wrong, the lever can be quite difficult, as it is not adjusted at the over-center point, but rather on the aggressive ramp before over-center.
The clutch cover is adjusted first, and then cable length is then adjusted for the correct lever position as well an full engagement/disengagement.
Cheers,