XT600 4pt oil pump air lock
 

Now then folk,

After replacing the main oil line from the oil tank to the bottom of the engine, there now appears to be an air lock/oil pump not catching oil, something I was worried would happen.

I have tried turning the engine over with the spark plug out and bleed screw on the oil filter cover out and no oil comes pissing out as it does with a regular oil change. I believe this is because there is air in the oil pump/passage to the oil pump. I can feel suction/blowing in the bleed screw hole, but it will not catch oil.

I have loosened the oil hose at the bottom and oil comes out of it, so no blockage there.

I have tried back filling the pump from the oil filter end, oil keeps filling into the hole, but doesnt fill up, and still when turned over, just air comes out.

I have even tried sealing my mouth around the oil filler hole and trying to create higher pressure in the tank, in lieu of having an air line, to push the oil though to the pump, but no luck.

I am a bit stuck, I dont want to just start the engine and hope the higher revs pulls oil through as there may not be oil to the head for some time, if at all, and cause damage.

Has anyone got any advice for priming the oil pump or a solution to the problem? Some special way of priming the oil pump, or is it ok to start the engine to see if oil flows.

Thanks

Ezra

system has a check valve in the right hand cover meant to avoid wet sumping, not surprised that initially it feels like pump is not pumping.


From my experience when the engine starts running the pump will create enough vacuum to overcome the check valve and let oil in.


If you are still worried/paranoid, then would disconnect the oil supply tube from the bottom of the tank, connect a big syringe full oil and push oil while a friend is hitting the starter for a few seconds.

You haven't done anything that everyone that rebuilds one of these motors starts with . What I do is pour roughly 1/2-2/3 quart oil in the motor through rocker cover caps , then the rest in the tank. Then I use 30wt or 20w-50w and squirt a bunch down a couple of the oil lines and check bolts , then start it up quickly . The motor can take a few seconds with no oil and by then it should prime up with the rpms . Keep the one bolt loose to see that oil is flowing .

I was hesitant to start the engine in this way since its been sat for a week and I reckon there wont be much oil in the head.

I will probably start by leaning the bike to the right and trying to get some oil in the passage to the pump from the oil feed hose, and try just turning it over again.

Then if that fails, squirt some oil into the inspection caps and see if it'll catch the oil with the engine running and hope for the best.

Thanks for all the advice.

I shall report back, either with a nicely primed oil system, or some nicely scored cam bearings.

Thanks

If your worried, leave one of the caps off and have an oil squirter filled with oil, then when it starts , slowly squirt oil in toward the cam . It'll be sufficient till she primes . Just don't get the tip of squirter pinched in the rocker going up and down . You'll know when the oil pump is primed , there will be oil splashing around heavily .

Well, decided to just start it up with the bleed screw off, within a couple of seconds of firing, a welcome spew of oil covered the engine and tarmac below.

Messy, but effective.

So I guess just starting them up works fine, cant imagine any damage could have been done.

Thanks for the help.

That's why a person uses assembly lube/paste when rebuilding a motor . The paste is the lube to protect components till oil is flowing good . take the rpms from a running motor to create enough suction to prime the pump . Otherwise filling the pump with vasolene or another petroleum based paste/grease will increase priming . Automotive motors I use a drill and a drive rod to spin and prime the pump without needing to start it .


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