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Oil pressure light on after engine re-assembly

I removed the nose cone again, checked the gears and keys, realigned the pump, blew out oil passages. I am now CERTAIN that the pump is turning. Back together, still NO oil pressure.

Maybe it's time to bite the bullet and take it to the Harley shop.
 
Mel Neff said:
I removed the nose cone again, checked the gears and keys, realigned the pump, blew out oil passages. I am now CERTAIN that the pump is turning. Back together, still NO oil pressure.

Maybe it's time to bite the bullet and take it to the Harley shop.
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Remove the top cap on the oil pump body, is there oil there?
 
HD91FLHT006.gif
 
You may of tried this already. The feed line comes from the bottom of the oil tank(pan) on the primary side about mid way of the oil pan according to the parts diagram. Is that correct? Have you disconnected that line, at the pump, push it lower than the pan and seen oil coming out of it? It should flow pretty good. I couldn't tell from the parts book where the return line went to the oil pan. I know it comes from the oil filter though. Just didn't see any thing labeled oil return in parts manual. It should be higher than the feed line and maybe on the clutch cable side, just don't know.
tourbox
 
Did you pack the pump cavity with vasoline? Pretty sure someone else already mentioned that, but I don't remember your reply to that specific question.
 
tourbox said:
You may of tried this already. The feed line comes from the bottom of the oil tank(pan) on the primary side about mid way of the oil pan according to the parts diagram. Is that correct? Have you disconnected that line, at the pump, push it lower than the pan and seen oil coming out of it? It should flow pretty good.

Yes, I've done that. Doesn't gush out, but is a steady stream.

I couldn't tell from the parts book where the return line went to the oil pan. I know it comes from the oil filter though. Just didn't see any thing labeled oil return in parts manual. It should be higher than the feed line and maybe on the clutch cable side, just don't know.
tourbox
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The return goes in the top near the dipstick.
 
Mel Neff said:
Does packing it with vasoline work better than filling it with oil thru the top cap?
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To prime the pump you need it to pull a vacuum on the inlet side long enough to fill the oil feed line. Just pouring oil into the top of the pump may not do that. Filling the pump cavity with a lightweight grease is what we used to do when reassembling a small block Chevy motor. I think someone else suggested putting a bit of positive air pressure into the oil tank. There is not just one right method to prime that pump, but you must find a way to get the feed line full of oil all the way to the pump.
 
Nice to know where the return line is, thank you. I never really paid any attention to it.
As far as placing grease, or a thick substance in the pump is not good IMO. A friend tried that and it wouldn't pump oil. It is designed to pump a liquid not a thick compound.
As Jennmarr suggested you might try 10-15 lbs. of air pressure in the tank to pre fill the pump. Remove your ball check valve and watch for oil to come out with the air pressure.
This is really confusing to me. Never had anywhere near this much trouble priming a pump.
tourbox
 
tourbox said:
As Jennmarr suggested you might try 10-15 lbs. of air pressure in the tank to pre fill the pump. Remove your ball check valve and watch for oil to come out with the air pressure.
This is really confusing to me. Never had anywhere near this much trouble priming a pump.
tourbox
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I did the air thing on my '92, pretty sure I had the return line to the oil tank disconnected, that way the oil went through the pump and filter making sure there was no air trapped in the system.
As Jennmarr said I think a vacum pump on the return line would work also.
 
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