Motorcycle Repair: 99 Road King Starting Problem, starter relay, starter button

Question
QUESTION: My 99 RK Classic will not start. It makes a feeble attempt but does not turn over. Thought it was the battery and changed it for a new one. Started right up so thought everything was good. let it run for ten minutes to warm up so I could change the oil. Shut it off and tried it again and it would not start. starter engages but acts as if the battery is dead. secong try makes clattering noise. Rolled it back into the garage later on and tried it and it started right up. Next morning won't start. Same thing first tries to turn over then clattering noise. Checked battery terminals all clean and tight, checked grounds on frame removed and cleaned all and reinstalled tight. Still same problem. Changed the new battery with the one from my Electra Glide which is starting fine. Still the same problem persists. Checked voltage at battery 12.79. Vpltage at starter 12.79. However when I check the starter voltage while pressing the start button it drops drastically downward settling about 1-2 volts. At the battery it stays about 12 - 12.5. Can't figure it out. could it be the solenoid?

ANSWER: At the wire from the starter relay to the starter, the small wire, what is the voltage when you press the starter button?
Mike

---------- FOLLOW-UP ----------

QUESTION: About 2.79v when the start button is depressed. Same as with the large cable. I don't have a shop manual (ordered) but the wires I have checked are on the right side of the bike if you are standing at the rear facing forward. I think they are on the solenoid which is above the starter (has a pentagon shaped end). I don't see any wires to the starter itself. Am I checking the correct thing? Also today I ran a jumper from the positive battery terminal to the connector on the solenoid where the small wire plugs in. Acts exactly the same with the clatter. And I can hear the start relay clicking when the start button is depressed with the small wire unplugged. I checked voltage on the relay with start button depressed and got 12.7v or so from one terminal.

Answer
If you have 2.79 volts at the small wire on the starter then unplug it and see what the voltage is at that wire when you hit the starter button. If its less than the battery voltage then replace the starter relay. If its 12 volts then you will have to pull the starter and test it.
Good luck and happy riding
Mike