There is a short little shaft that is between the clutch lever and the master cylinder. That goes into a brass "barrel" in the clutch lever. That "barrel" gets worn and won't let it trip the switch.
Those parts have nothing to do with the switch.
If it's the clutch switch not working that is causing the problem, there are most likely causes:
1. The pivot hole in the clutch lever is worn out, preventing the handle from fully depressing the switch. The fix for this is to replace the lever. You can test this by temporarily shimming the surface of the lever that contacts the switch, enough that you hear the switch click when you pull in the clutch lever. Then see if this allows the bike to start while in gear.
2. The switch itself is faulty and needs replacing.
