/5 oil flow issue

[Craig Barnhart]

Greetings Airheads,

I have an oil flow issue on my newly assembled 1972 R50/5 project bike, and
I'm scratching my head trying to determine the next steps.

This is the first time I ever attempted to start the bike, and I am not
getting oil from the sump to the cylinder heads, and only a residual amount
to the oil sensor (oil pressure light stays on).

*Background:*

As part of this three-year (part time) project, I replaced all seals
including the fuel pump's o-ring and cover, the woodruff key, and visually
inspected (no measurements) the fuel pump. I also replaced the pickup
gasket.

*What I've done since the issue, not necessarily in this order:*

   1. Read thru this thread:
   https://advrider.com/f/threads/airhead-oil-priming-problem-ha.746898/.
   The *Bill Harris, Dec 5, 2011 *entry is the best summary on the page.
   2. Studied Snowbum's diagram and notes:
   https://bmwmotorcycletech.info/oilsketch.htm
   3. Tested the oil sensor switch.
   4. Filled the oil filter cavity with oil to prime it (laid the bike on
   its side to fill--learned this trick from Tom Cutter).
   5. Hand pumped (as best I could) oil into the oil sensor hole to prime
   it.
   6. Visually checked the pickup, bolts, and gasket
   7. Blew air (with an air compressor) into the pickup and felt air coming
   out of the right cylinder.
   8. Blew air into the oil sensor hole.
   9. Blew air into oil filter cavity holes.

*Outcomes after turning over the engine (spark plugs out; green coil wire
off) for 90 seconds at a time:*

   1. I got a tiny bit of oil into the left head (right side of the left
   head) at one point of the process.
   2. Oil is coming into the oil filter cavity.
   3. There is residual oil in the oil sensor hole (seeps out when sensor
   is removed), but it doesn't flow out when turning over.

*AFAIK this is what is left to check:*

   1. Oil pump - Visually inspect again and take measurements this time
   (remove flywheel, etc.)
   2. Oil pressure relief valve - Make sure it's not stuck open (remove
   timing cover)
   3. Ensure front main bearing cap oil passage hole lines up with engine
   block hole - Not sure if I can do this visually without removing the main
   bearing or cap  (remove timing cover)
   4. Something clogged in the system - I don't know how to check this
   other than blowing air through it.

*Questions:*

   1. Can I narrow it down to one area before disassembling the rear and/or
   front end?
   2. Is there any way to test the system after disassembling besides a
   visual inspection and measurements?
   3. I can tow the bike to Chris' tech day if anyone thinks it would help
   to see it in person. Does anyone think it would be helpful to bring it?

Thank you!
Craig
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