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

Question
QUESTION: 1989 XLH 1200 When engine is cold oil pres. is good. When warmed up after riding oil pressure goes south gauge reads 0 and oil light comes on at idle. Put in new oil sender and added oil pres guage. Has new oil pump and oil tank. Removed oil cooler and used 50 weight oil with lucas oil. It got better just took a little longer to come back to the same problem

ANSWER: When your riding the bike down the road you have zero oil pressure when the bike is warm or is it just at idle? Looking in the oil tank, when the bike is at idle an dreved up a little do you see a return flow?
Mike

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

QUESTION: After about 1/2 hour of riding the oil pressure gauge goes to 0 psi. while you are still riding. When you come to a stop the oil light comes on. light goes out when you get up to speed again and oil pressure gauge stays at zero or just a little above zero. There is a return flow back into the oil tank when the bike is hot or cold.

Answer
Since you have changed the oil pump and still having the same problem the only two rersons that would cause your problem would be a pinched or restricted oil line and the other is the check valve is stuck which is located in the oil fiter mount.
Good luck and happy riding
Mike