Adding a gasket would influence the spring for the check ball.

Remember, adding a restriction increases pressure but reduces volume. I think that's the restriction to add enough press so light doesn't pop on at idle. It doesn't affect anything to engine and should not even bee needed at upper engine rpm.

When you remove the gasket, make sure spring and ball are there.

I thought the anti drain valve check was in the oil entrance?? Are they on the back side. An entrance from oil bag and a exit for the flexibility line to oil filter.

Harley's mostly have needle and ballbearing. Sporty has those sleeve bearings in the gear train. The don't need a lot of pressure nor will they hold it do to loose tolerances.

Just the as designed volume is enough to get oil thru motor.

Car motors are different in that they have volume that pushes thru all those close tolerance bearings. This creates pressure. The volume is however designed to have enough pressure to get oil to the furthest bearings in the heads. As things wear, failures occur. So they need probably three times what's engineered into a Harley.

 

I understand that there is no gasket at the sending unit. What I was referring to was a gasket in between the oil pump itself and the nipple that the sender screws into. I looked at some pictures and diagrams, not all years of Sportster have these apparently. Some years the sender screws directly into the pump.

 

Absolutely, in a car engine the bearings rely on a high pressure hydrodynamic wedge of oil to prevent actual contact. In the bike engine the needle bearings don't require the same pressure. But as I said in my original question, it would seem that putting any kind of gasket placed between the nipple, # 2 in diagram, would totally block the passage that goes to the sending unit. While it wouldn't effect actual pressure to the rest of the engine, it would block the flow of oil that would create enough pressure to open the normally closed contact in the sender itself. I'm a pretty decent mechanic, not a Harley expert by any means. This is my first Harley and I had no idea whether or not there was supposed to be a gasket there or not. Possibly someone before I owned it put it in there by mistake? If I get a chance tomorrow I will take it back apart and take pictures. It much easier to see in a photo!

 

Easy to see in this video the tiny hole in the nipple

 

And again we see all Harley's are not the same. That check is much further inside the oil pump. The check body even though that person had sealer on the threads appeared to be a straight thread part since it was bottomed on the pump.

I think it's straight thread and requires a face gasket. (From here). Sealer tap and such are really not designed for straight threads.

Probably doesn't hurt anything but if you use both, don't let it hang out on front of thread and break off. Last thing you want is it under that ball.

The center section has nothing to do with pressure switch. Later years have that pressure switch further forward mounted on side face of oil filter.

We just went round and round on that one. User had split case screwing it in two far.

I suggested he cap the crack with a thur bolt and gaskets. (Over other suggestions of welding). So of course, things went round and round and I added a few name callers to my ignore list. He capped it.

Relocate pressure switch on a T fitting. Where your pressure switch is was a discharge hose heading to filter.

 

It has a read light though, which is why we are talking?

 

There are 3 gaskets for the oil pump, taken from my Factory Parts Manual.
1 - 26256 - 52 pump to crankcase
2 - 26258 - 52 upper pump gasket
3 - 26259 - 62 bottom pump gasket

NO OTHER GASKETS ARE NEEDED

My Ironheads, PAST - 1972, 1975. Curreny 1977. So I've got a "little experiance" with the Beast.

I'm done here.

 

Thank you kindly! There is now no doubt in my mind what the issue is!

 

UPDATE: I did finally get back to the issue. Took it apart ,pitched the useless gasket, problem SOLVED!!! Of course it would seem with these bike when they bought second hand, you fix one issue and find another one. During the process I discovered that at some point the check ball and spring had been completely removed!!! Now when the engine is cold the light does go out, but once it is hot, the light comes on at idle. Not sure what role the check ball and spring play in that issue. From what I read that is a gimme with these bikes, hot at idle, at least the light flickering? I will be getting the correct check ball and spring and installing them. But hey, the light goes off, that's progress, right?

 

Appears it is the idle fix for the light and anti-drain. If you look at PDF Page 2 closely. The ball check is overridden at speed. Later models are under the filter just for the light and the pump has the anti-drain there.

When you put a restriction in a line, it increases pressure. It does this by a loss in flow volume. At low idle speed, the pump doesn't have enough pressure without that slight restriction.

bet if your bike set a long time, the oil bag is emptied.

My old Softail if it sets much over 4 months, bag empties because the o-ring in the pump is worn I guess. It takes quite a few blocks of low-speed running to refill bag since it's also pulling oil out.

That oil pump design was used 59-69 and on a limited amount thru 76