The CT3 sat for many years. Had to cut off chain- tires were frozen, engine was free. Engine is on the bench and the bike is coming back together. I connected the battery (6.2v) and there was a slight horn sound coming from my horn when i was connecting it but stopped after the connection was made. I seem to have no power to anything and was wondering if the engine circuits were needed to me made up or is the lighting, horn, stand alone systems that only rely on the battery?  The switch handle was not working and i got it free with contact cleaner, and when i test it for current I see no signs of life. Testing at the horn with the switch on shows nothing and nothing when jumpered straight from the battery to the horn. How is the horn getting the initial weak current if the switch is bad? Any electrical advice including start up steps to check would be very much appreciated.

Your doing right in cleaning all connections.

The horns are temperamental little buggers. They should work if connected direct to a battery - just put the + to one horn terminal and the - to the other (doesn't matter which). 

Installed a new brake switch and I have signal to the rear brake light. Ordered a new horn ( old electrical is tough sometimes ) and I will use it to test my other wires.I should hear success-lol. I have a feeling the handle switch may need to be replaced. Always a tough find, but that is the fun in it sometimes. Scrubbing all of the grounds I can as I do not have a headlight ( new).

Look at wiring diagrams.
Horn has full power to it with key on.  (brown)

Button on handlebar grounds second wire to horn (pink) to make horn beep.