What really stands out would be the crank sensor. Disconnect the crank sensor. Hook an AC voltmeter to the 2 sensor wires. Crank the engine and see what you read in AC volts. Also take an ohm reading of the crank sensor.
Not sure if this will work on a carb Sportster for codes but try it.
I'm going to try and pick up where i left off this weekend. A friend of mine is going to come over and help me try to figure this out. I'll let you know the outcome.