What type of oil goes in the pump, and is the tube that comes out of it on the top of the pump supposed to be open or a covered vent??

Ur makn it tu complicated to follow..how does it run..gimme details

There's a spring loaded check ball that is suppose to prevent oil from gravity feeding past the oil pump when the engine is off. Over time, the seat could pit, or the check ball itself could get a groove worn in it from the seat, or the spring could weaken (take a "set").
If your's is all original, let's face it, it's 42 years old!
You could try a new ball and spring and see if that helps.

BUT, if it sat a looooong time, no matter what, SOME oil most likely will seep past the check vale, and get pumped out a vent.
If after running a bit, and it doesn't do it again, I wouldn't worry about it.

There ae a number of things it could be. What it sounds like to me is that the oil is not being pumped back into the oil tank and is collecting in the cam chest. It should be blowing out of your crankcase breather tube as well if your crankcase breather tube is open. Behind the oil pump, there are three holes. One is behind and above the oil pump. This is where the breather tube from your oil tank and the primary comes into the engine. The hole directly behind the oil pump in the middle is the oil return line from the very back end of the primary where the oil from the primary is recirculated back into the engine. The bottom hole behind the oil pump is the crankcase breather. It should have a hose that runs back around behind the transmission and just dead ends in a bracket pointed towards the final drive chain. This hose should be open to vent the crankcase pressure. Have you checked to see if oil is being pumped back into the oil tank? If not, the scavenge gears of the oil pump may not be pumping the oil out of the engine and back to the tank. If this is the problem, you may not have the drive key properly installed in the scavenge gears of the oil pump. Still, oil should be pouring out of the crankcase breather hole. But, this is what it sounds like it's doing to me. The oil is building up in the cam chest for some reason.

Good Luck
steve

It is more likely that the oil is coming into the air cleaner by way of the CrankCase Vent.
There should be a tube that goes from one of the Valve Covers directly to the Air Cleaner.

Inside the AirCleaner Housing, there is the Air Filter, but there should also be a much smaller filter, sort of held in a little box, where the tube from the valve cover comes in.

This condition usually manifests when the vehicle has very high miles. It is caused by excessive BlowBy in the cylinders to the CrankCase. It will help to Change the Positive CrankCase Ventilation Valve. If it is plugged, it will make the situation worse. So, get a new PVC valve, and that is about all you can do, except to keep the air cleaner new, and the oil topped off.

if you go to sears parts you should be able to see a parts diagram and see if all the parts of the pump are as they should be from what i know there is a piston that moves up and down there are two sides to the pump head the top piece and the muffler with the filter lets air in the other side has the flex hose it isn't to complicated to take apart make sure parts are in the right order on diagram . i think the parts can be dry oil isn't going to hurt any thing though just make sure you don't have to much in the fill tube the bottom of that tube should only cover the little gear in the see-through port half way any more than that and oil and air will come out that tube

Without seeing the bike, I would guess that this is the crankcase vent. Originally, the crankcase vent tube came up from behind the oil pump and went to the backside of the air filter. A lot of owners changed the routing of this hose due to oil being blown into the air filter. They simply remove the metal part of the tube and replaced it with a short open ended hose running back and ending just forward of the rear tire.

As for the oil blowing out of the tube, it depends on how much oil blows out of the tube. If it's just a mist that will sometimes coalese into a droplet, this is about normal. But, if it's a steady drip or flowing oil, this is not right.

If the mist is heavy, this could be caused by excessive blowby on the rings creating high crankcase pressures. The use of synthetic oil should not increase the blowby unless the rings are in poor shape, then it will. The use of synthetic oil seems to aggrevate any minor leak turning it into a much larger leak.

If the oil is coming out in a steady stream or pumping the oil out of the engine, you proabably have sheared a key in the scavenge gears of the oil pump and it's not pumping the oil back into the oil tank.

Now there is a vent hose on the oil tank but it should be routed to a fitting on the crankcase that is located just above and slightly behind the top of the oil pump.

Good Luck
Steve

I can send you a diagram but not through this forum. The file size limit here is 150kb. Contact me directly and I'll send you a drawing of a later model but the oil line connections are the same.

Basically, the input oil line comes off the bottom of the oil tank and goes directly to the backside of the oil pump. The oil is pumped through the engine and then scavenged by the oil pump. It' is pumped out the front side of the pump to the oil filter if it has a spin on filter on it somewhere. If not, the line goes back to the oil tank and connects right at the cap. This oil tank uses the drop in type filter or the filter that has a replaceable element in the cap. The only other oil line is a breather line that comes out of the cam chest just in front of the front chain sprocket, you'll have to take the chain sprocket cover off to see it. It goes up and behind the oil tank to the small hose connector. That's the breater vent for the oil tank. The vent that comes out the front of the cam chest has a pipe on it that comes down and dead ends. It doesn't connect to anything.

good Luck
steve

Ok, you have two ventilation hoses on the bike. First, the oil line from the tank goes to the inlet side of the oil pump facing the rear of the bike. The return line comes off the front side of the pump and goes to the oil filter. From there, the return line goes to the return fitting on the oil tank.

Now, there is one crankcase vent hose that comes out of the cam chest behind the front chain sprocket cover and runs to the backside of the oil tank. Then there is another one that comes from the top front of the cam chest and goes to the backside of the breather.

Now, the older Sportsters were notorious for shearing the scavenge gear drive pin. When this happened, the pump would pump all the oil into the engine but the it couldn't pump it back out. The engine would be full of oil, literally. Oil will come out of every seam on the engine. Look in the oil tank and see if it's dry. If so, the oil is all in the engine.

If this turns out to be the case, I can tell you how to replace the drive pin but it's not a job for the faint of heart as I recommend pulling the engine out of the frame. It can be done with the engine in the frame but in my opinion, it's a lot harder.

Good luck.
Steve

Check the metal vent tube on the fuel pump. When the diaphram goes out, oil will leak from the vent tube. If that is the problem, get it fixed pronto. Not always but there are some times when fuel gets mixed into the oil when the pump is going out and that thins the oil out. Keep on driving with this problem and you can kiss your engine good bye.

When/if you change the fuel pump out, make sure not to lose the push rod that is behind it. It goes between the camshaft and fuel pump.