Submitted by: Pococj

Seems to be a long-time problem with Harley’s that oil in the tank will drain through the oil pump and fill the crankcase. When the tank is checked it appears low and more oil is mistakenly added. Or the bike is started and the oil in the crankcase is blown out the vent all over the ground on older models, or into the air cleaner and then onto the bike and ground if it’s a newer model.

One culprit is a check valve that is supposed to prevent the drain-back into the sump. If a piece of trash gets lodged between the seat and ball, or the ball gets a groove worn in it over time, or the seat gets a slight nick in it, oil will leak past and the mess described in the paragraph above happens. A couple other problems may cause wet-sumping, too. These are a loose idler gear shaft in the pump body, or a leaking oil seal at the pump drive shaft. These last two are beyond the scope of this article.

Generally the check valve is easily inspected and repaired. It is possible that the oil pump will have to be removed for repair, and even that the oil pump body might have to be replaced. These last two are seldom necessary though. The following procedures will usually fix the problem, and further disassembly won’t be required.

First acquire five (5) new check ***** for your particular oil pump model. You might not need all of them, but the unneeded ones can have an alternate use. Drain the oil from your tank, and remove the plug and spring above the check ball. You can find the location of the plug by referring to your service or parts manual. (You do have a service manual, don’t you?) Fish the ball out of the hole with a magnet. Do not pry it out with a small screwdriver or any other device. Prying it out might cause more damage by scratching or gouging the seat. Take that ball and stick it in your pocket. Don’t use it in your oil pump again.

STEP ONE

Clean out any debris and oil. Use a flashlight and a magnifying glass to inspect the seat. If the seat has any scratches or dings in the seat, it’s time for STEP TWO. If the seat looks good, drop in one of the new check *****. With a brass drift and small (emphasis on “small”) hammer give the ball a smart rap to seat it. If you ham-hand this you will screw up the oil pump body and get the privilege of buying a new one. Now remove this ball and stick it in your pocket, too. Drop another new ball into the hole, replace the spring and plug, add oil to the tank (don’t overfill), and try the beastie out. If the wet sumping stops, you’ve solved the problem. If not, it’s time for STEP TWO.



STEP TWO

This step is only necessary if the seat is messed up, or the wet sumping didn’t stop after performing STEP ONE. You’ll get to make a special tool to do this. That puts you in a league above 99% of HD tinkerers.

The tool is simply a welding rod attached to a new check ball. The old way of attaching it was to weld the rod to the ball by touching the rod to the ball while the rod was in a stinger, with the machine at about 65 amps. If you’re a welder, or know one, this works fine. Be careful and don’t mess up the ball, though. Another way is to mix up some epoxy glue and glue the rod to the ball. If you let it cure sufficiently, this works almost as well as the welding method. It has the added advantage of not screwing up the ball for us less-than-stellar welders. Once you’ve made the basic tool, slip a piece of rubber hose over the rod. That’ll make it easier to operate the tool.

Now to the meat: Coat the end of the ball with a very fine lapping compound. Some mechs use valve lapping compound, while others use something like Simi-Chrome. You can even use one followed by the other, if the seat damage is more severe. Put the coated tool into the oil pump and lap the seat as you would lap a valve seat, by spinning the tool rapidly back and forth in the palms of your hands, while exerting a sli

 

Was wondering if this would be the same for a 77 sportster? or is it diffrent? would the pump have to come out? or is it possible to replace it in the bike?
mine ran great then one day primary feld up with oil and the oil tank drained.
any info would be appreciated on this.

 

You're primary filling up would have to do with your main seal behind your stator. Pull the primary and see if your main is leaking from around the case or the rubber around the shaft. You might have to use 1500 grit sand paper to polish the shaft race that the rubber rides on if there are any nicks or scratches. Or you might just simply have a worn out seal. Just be sure to inspect and clean everything before you re-install a new main seal. Also make sure that it goes in square and only press it in flush with the case wall.

 

I know this is old but I just wanted to say thanks. I just utilized this tonight

 

Could tipping the bike over nearly upside down cause the ball to become unseated and let the oil spew out of the crankcase breather hose at the filter but only when I try to start the engine? Any one know of this ever happening before?

 

How do I get the rest of the instructions in first comments by Pilot1996 in this thread?

 

that will not work and it may lead to other issues. when you peen the seat, the metal has to go somewhere and that usually is the easiest route down the hole. this metal movement can distort the seat. you can have success with cutting the seat, but that is not going to happen using a ball welded to a rod, it requires precision seat cutter. the oil molecules are quite small and will still leak past the seat.
also, hd did not plan on pump repair, hence no meat to play with, they consider it a wear replaceable part.
i will say that probably in the 90% range the oil is NOT leaking at the seat!!!! its more likely route is through the pump itself via the shaft before it even gets to the check.
also, hd changed design years ago on how the seat is cut. they went from conical to tangent, aka wide seat to narrow seat which requires precision machining, your method will revert back to the old style. why the change??? remember the seat pressure from the spring is only so much and if you narrow the seat, less surface area, more pressure at contact point!
another issue is that hd did not use seals on the shaft tower, only between the feed/scavenge.
for the iron, they had some dude selling modified plates that he added a seal to but it was north of 100 dollars, truth told, done for 50 buck or less depending upon what equipment you have. there is no need for precision mill, a good tight quill drill press will work.

http://xlforum.net/forums/showthread.php?t=2047100