Motorcycle Repair: Ignition Problem?, modual, vapor lock

Question
QUESTION: Mike,
I have a 1991 sportster.  Started it up one morning like every other morning, let it warm up, jumped on and 3 houses down the street it died like it had no gas.  I check gas flow and it was good, but when I tried it again...nothing.  Checked spark and had none, replaced coil, plugs, wires.  Tried again nothing for the first little while and then it came to life, warmed up and died 4 houses down the street, again no spark.  I have now ordered a new ignition module, based on HD service tech description of similar problem when I went to get coil and plugs.  I have looked through wiring and found no apparent bare wires or shorts.  The bike was sputtering, and cutting on when hot, but it has after-market tank with gas line between cylinders so I thought vapor lock, but service tech indicated this may be due to ignition module going out.  My question is am I on the right track by replacing the coil?  Or do you have a different direction I should take.   Thank you so much for your help and all the answers you give here.

ANSWER: SInce you replace the coil and it didnt help it can only either be the ignition modual or the pickup.
When it shuts off check with a test light at the coil to make sure you have power. If not then you have a short.
If it tests ok then I would test the pickup and finally test the modual. If youhave a bad pickup and you replace the modual you havent accomplished anything.
Good luck and happy riding
Mike

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

QUESTION: Thanks for the quick response.  I tested power with a multimeter to the coil with no spark and am getting 12 + volts.  I had to special order the module and they say there are no returns.  While I am waiting, I would like to test the pickup, can you tell me how?  Thanks again for all your help.

Answer
Your best bet is to get a service manual to do the tests. There are about 15 test for the modual and pickup and would really be tough on here to tell you how without pics.
If the tech told you the modual was bad and its not, then not sure why you cant take it back. They are the ones that told you you needed it.
Good luck and happy riding
Mike