Suggestions for priming the oil pump? YX600 Radian

Help, my oil system will not prime!

I recently had the engine out of my '86 radian and had the clutch /
oil pump cover off. While the engine was out I cleaned it and gave
it a Dupont overhaul (repainted portions and powerdercoated others).
Prior to removing the engine I drained the fuel diluted oil. When the engine was out and the clutch cover was off I got more oil out when it was
tipped in various directions, etc. The engine did run prior to removing it from the bike.

After reinstalling the engine in the bike, filling with oil and
reassembling most of the bike, I turned the engine over by jumping
the starter solenoid (no fuel / no spark) for a 30 seconds at a time
to prime the oil system. I cannot get engine oil to fill the oil
filter and out of the oil system check hole (bolt on the RH rear top
of the cylinder head near the rear camshaft). My sense is that the fuel diluted oil drained completely from the oil pump so it lost its oil film seal and ability to create a vacuum to draw oil into the pump and pump it through the oil delivery system in the engine. I have attempted to get oil back into the pump by squirting oil into the oil delivery passage to the oil filter. I have not started the engine since reinstallation as I am concerned that I will quickly damage the bearings with no oil in them.

Any suggestions? I'd prefer to not pull off the clutch cover (again) and
clutch to pack the oil pump. This being said, I'd rather do that than cause further damage to the engine.

Thanks,
Dan

 

As long as you didn't take things apart and not reassemble them correctly the oil pump should prime itself.
I'm not familiar with your model, but maybe you can get oil to the pump via the oil filter passageways?
In most situations I've usually applied oil to all reassembled items to prevent metal to metal contact prior to the oil pump doing it's thing.

 

Update: to prime the oil pump, a friend suggested pressurizing the engine through the crankcase breather. With the oil filter off and the threaded center hole of the oil filter mounting plugged, I applied 10-15 PSI air pressure to the crankcase. Within 20 seconds, oil was flowing from the oil passage from the oil pump. I then turned the engine over again by jumping the starter solenoid. With oil (vs. air) now in the oil pump, it pumped oil perfectly! I then reinstalled the oil filter and turned the engine over again; I quickly had oil flowing out of the oil system check hole near the valve cover.

 

I've never heard of Yamaha Oil Pump being "Air Bound".
The design of the Pump make it self-priming?

How many miles are on the old Pump.
Did you measure the tolerance of the Impeller to the Pump Casing.

You might be looking at a bad Pump.
If I were you, I'd consider replacing that Pump rather than trying to get it to Pump if its not!

I'm thinking something isn't right with the Pump.
A good Pump will self-prime after a rebuild by pulling the Plugs and running the Engine on the starter for a few 20-second intervals.

Even if you do manage to somehow get it to start pushing some Oil ... I'd be worried about it quitting on me and making life miserable for not replacing it at the first sign of trouble.