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Oil pump priming.... Is it needed?

Butscut

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Hey folks. I have just rebuilt the top end of my 1982 CB750F supersport engine which included engine removal, flipping it over to remove the oil pan and reassembly. Although I didn't rebuild the oil pump when I flipped the engine some oil came out in the vicinity of the oil pump so I fear that oil that was in the pump may have drained out

Qn. Before I fill the engine with oil, will I need to remove the oil pump to prime it or will it self prime?

Thanks
 
It will more than likely self prime. The sohc do have a tendency to lose prime, they are a bit more problematic with two pumps. In sohc the best way is to submerge the pump in oil and turn it over then reinstall into the engine. Another way on the dohc for instance would be to use a pressurize oil tank and pressure oil the engine through the sending unit....which is what we do in the automotive field before fireup of new or long sitting engines. In your case you could crank it for a short time with ignition cut off and spin the engine with starter for several seconds to pump oil around the engine....better would be to pull all spark plugs as well so engine spins free.
 
It will more than likely self prime. The sohc do have a tendency to lose prime, they are a bit more problematic with two pumps. In sohc the best way is to submerge the pump in oil and turn it over then reinstall into the engine. Another way on the dohc for instance would be to use a pressurize oil tank and pressure oil the engine through the sending unit....which is what we do in the automotive field before fireup of new or long sitting engines. In your case you could crank it for a short time with ignition cut off and spin the engine with starter for several seconds to pump oil around the engine....better would be to pull all spark plugs as well so engine spins free.
Thanks pal, I have just done as you suggest and I am now seeing oil pressure meaning that the pump is definitely working! On the down side it now looks as if I have a small oil leak coming from the new gasket just above the cylinder head. 😵‍💫
 
Valve cover gasket leak, it sounds like.

When you install the four chrome caps into the gasket, I would recommend using black RTV between them and the gasket itself. The manual also recommends a dab of RTV at the sharp corners where those caps fit.
 
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