Motorcycle Repair: CB450SC clutch lever start switch, clutch lever, starter clutch

Question
I just bought a 1985 CB450SC Nighthawk with only 1200 miles.
I have everything cleaned and tuned; except when I start the bike the clutch lever safety switch does now seem to work....the bike starts without having to pull in the clutch lever.  I already checked continuity on the switch itself...it's OK.  Does the starter clutch diode under the left side panel have anything to do with this clutch lever safety switch ?  Where should I trace this circuits wiring for trouble shooting this problem?

Your expertise would be very helpful,
Sterling, Pittsburgh, PA

Answer
Sterling,  is the plunger still in place, extending/retracting when you activate the clutch lever?

http://www.cmsnl.com/products/switch-frlever_35330413003/

The switch will be normally closed when the lever is pulled or the plunger is broken off. Circuit is open when lever is at rest and plunger is intact and being pushed inwards.

A wiring diagram is shown here:

http://oldmanhonda.com/MC/WiringDiagrams/MCwiring.php#class  

The diode is part of the starter system and should only flow current in one direction.

Bill Silver