Double and Triple Check that all your connections from Wires to Starter are tight and corrosion free, My 07 Low Rider was very fussy, The original owner had Sanded down the connections one day to clean them,,,, Well that just caused hidden corrosion.. It would click and turn over slow, Some days it would Start right up ,, ride 15 miles shut it off and go to start and you would get click click click,,,, Clean connections and good to go...

Worth checking before you go deep into buying parts

 

Rapid clicking of the starter solenoid is a classic symptom of low voltage.

How old is the battery?

How was the battery tested, was it a load test?

 

Read page 1. I tried...

 

Battery needs to be load tested, not just voltage checked. Be sure that was done first.

 

You said "Battery was tested as good by two places", which could mean some goofball tested the voltage with a voltmeter and said it` good...

It must be load tested.