From much rooting around in mine recently, here's the deal:
1) Black is frame ground. No voltage reading.
2) Orange is the negative signal for the coil, think of it as serving the same function as the points lead on that type system. This wire makes and breaks the ground for the coil so there won't be a voltage reading. You could possibly connect a small test light between +12V and this wire (such as across the coil connector, from red/white to orange), then turn the engine over and look for a pulse. I wouldn't use a big light bulb, use a small one like a instrument bulb or an LED.
3) Black with white is the ground for the pickup coils. Again no voltage reading.
4,5) White/red stripe and white/green stripe are the pickup coil signals. No voltage out from the box, but there will be a signal voltage from the pickup. You may or may not get a voltage reading when the engine is turned over. If you check from either of these wires to the black with white stripe you should get around 700 ohms. (This is on the harness plug, not the TCI box plug.) Somewhere I saw that if you connect an analog voltmeter between either of these wires (again on the wiring harness end) and the black/white and wave a magnet past the pickup you will see the needle move, indicating a pulse.
6) Red or red/white stripe is battery voltage, measured on the harness side.
The bikes with a sidestand kill switch have a 7th wire which goes to that kill switch but I don't know what color that wire is. I think it is white with a black stripe.
