Motorcycle Repair: 76 sportster oil pressure, oil gauge, oil tank

Question
QUESTION: I just bought a used 76 sportster that has no oil pressure at valve train when engine warms up. Oil pump pressure at sender when warm is 20 pounds.  Why is there 2 return lines to the oil tank?  Should the smaller, cam return line have a restrictive device?

ANSWER: One line is return, the other is vent. What location are you talking about when you say the valve train?
Mike

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

QUESTION: There are 3 lines to the oil tank.  One on the bottom, one by the cap, and one on the upper side of the tank.  Which is the return and feed lines?
The rocker arm area which is where the mechanical oil gauge is.

Answer
The lowest line is the feed. the one at the cap is the return and the other is the vent. On the gage, you might have a bad gage. If you hve 20 lbs of pressure at the sending unit then you should have 20 lbs at the gage as well.
Good luck and happy riding
Mike