Motorcycle Repair: CB160 idling issues, needle nose pliers, clymer manual

Question
When I rev my 1965 CB160 up to several thousand RPM, it takes 3 or 4 seconds to slow back to the idling speed of 1000 RPM.  When riding, the engine actually revs up when I pull the clutch lever to shift gears.  The throttle/cable system works freely and immediately drops the pistons in the carb to the home position when I let go.  I've gone through the carb adjustment procedure and the ignition system procedure in the Clymer manual.  Put new carb kit rebuild parts in both carbs. Ideas?

Answer
I'm betting the timing advance unit springs are worn out allowing the timing to advanced when it should be retarded.  I normally just take a pair of needle nose pliers and pinch the loops on the springs closed a little to increase the tension on the springs.   

Regards
Rich