Air bubbles in one oil line

[premiumjo]

Cannot seem to get the air to bleed out of the oil line going to the left cylinder. The right side primed up quick (I ran a little premix and held the oil cam wide open til it was solid). The left side just keeps pushing air through mixed with oil. Is this a problem with the pump? the line going the injection point looks fine. I have another pump off a donor bike I can use if I have to. Any Thoughts?
thanks
rd

[OldSwartout]

My guess the check valve attached to the rotary valve cover is leaking and letting the crankcase vacuum pull oil in, which can also pull air into the line through the pump from inside the gear drive cavity, or even worse, if you have a split hose or bad sealing washer at the union bolt.

There could be something wrong with the pump internally. If you are sure the check valve is Ok, the pump can be disassembled for a look.

Someone else chime in if they've got other ideas.

[rwgibbon]

I would check the supply lines to see if they are cracked.

Look at where the line connects to the nipples. I have seen
them crack there.

Just a thought.

Good luck.

[grundlegrabber]

I was having the same problem with my GTO when I first got it running. Took the check valves out, cleaned & inspected to make sure they were working, and they were OK. Then I realized I had the oil tube going to the left cylinder pinched betewwn the carb and the engine case. Took carb back off, adjusted fitting on oil pump to get the oil line to run in a little different direction, and it was OK. It did still take longer to get all the air to bleed out of the left side than it did on the right. And it probably took 7 or 8 minutes of running to get all the air out of the lines. Idled while holding pump cam wide open, revving it every so often.

[premiumjo]

wow. thanks for the input. I did find a crack in the hose at the pump nipple, but that didn't cure the problem. I swapped the pump out with another one I had and all is good-nice solid oil flow. Now I just need to find a new washer for the bleed screw-it is leaking out of there. My poor garage floor...........
Thanks again.
rd