Board index Flathead Power-Technical Questions, Answers, and Suggestions Knuckles Oil Pump Check Valve

Oil Pump Check Valve

Post Wed Oct 26, 2016 11:41 pm

Posts: 2
Hi,

I have a 47 with an S&S oil pump.

The primary oil feed keep dripping even when the engine is not running.
This can be quite a lot of oil when the bike has not been used for a few months.

Should the oil supply to the primary chain be stopped by the check ball in the pump when the engine is not running?

Any advice or confirmation of the above would really be appreciated.

Rick

Post Thu Nov 17, 2016 1:09 pm

Posts: 154
Location: Carver, MN

Hi Rick, since no one else has offered a comment I'll give it a shot. The short answer is that the primary oil feed is "downstream" from the check ball, so that should keep oil from the tank from entering the breather. That leads to a couple other questions, though. Have you confirmed that the oil is definitely coming out the breather tube when parked, and not just accumulated oil in the primary cover leaking out? If it is coming from the breather tube, how long does it continue to drip? For instance if you were to put a small container at the opening of the breather tube, and check and clean the container every day, does it continue to drip? (providing you don't start the bike in between checks of course) If it continues to drip, then you might try disabling the primary chain oiler needle by seating it lightly - if the drip continues it is likely a symptom of seeping past the check ball and filling the gearcase up to the level of the breather tube. Probably the first attempt at curing a check ball issue on a modern pump would be to remove the ball and run the engine to attempt to flush out any debris that may be interfering with it seating. If that fails you would move on to the other common methods of re-seating.

Post Sat Nov 19, 2016 2:48 pm

Posts: 2
Hi Lee - thanks for helping.

I have the primary cover off and get a drip about every minute.
If the bike sits for several months it will eventually drain the oil tank.
I can reduce the oil by screwing the needle valve all the way in but it does not stop it.

That helps to know the oil should not be getting past the ball valve.
Will try to reseat the ball and see of that works.

This has been going on for some time now I am motivated this time to try and get it corrected.

Rick

Post Sat Nov 19, 2016 3:35 pm

Posts: 3222
Location: Central Illinois, USA
The Sumpmonster will not die!

My own attempts ended in humiliation:
Although an aluminum body may be far more forgiving than the cast-iron (or cast steel) bodies I dealt with, I was forced to disavow the burnisher idea after finding that not only were some pump bodies “chilled”, so hard as to damage the burnisher and the pump, but also that many of the threaded portions for the pilot caps were not concentric with the hole, rendering them useless.

Perhaps an S&S pump might have better quality control on this?

Bubble-testing of a checkvalve on the bench...
CHEKTEST.jpg
...soon proved that only a flat grind from the top with a tool as shown in the attachment could remove a worn seat, and improve its seal.
CHEKSTON.jpg

All other attempts at lapping, grinding, cutting, burnishing, or smacking with a drift only made things worse.

Believe me I am sorry, as I lost an enormous investment, and a lot of valuable time, trying to solve this very pesky problem.

....Cotten
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Post Sun Nov 20, 2016 12:44 am

Posts: 54
Location: London, England
Cotten wrote:
My own attempts ended in humiliation


Don't put yourself down. Disappointment would be a better word.
Ron

Post Sun Nov 20, 2016 9:37 am

Posts: 3222
Location: Central Illinois, USA
rocket ron wrote:
Cotten wrote:
My own attempts ended in humiliation


Don't put yourself down. Disappointment would be a better word.
Ron
I"m disappointed daily, Ron,

But letting down my people goes beyond that.

.....Cotten

Post Sun Nov 20, 2016 1:23 pm

Posts: 1120
Location: Ojo Caliente,NM,USA
But letting down my people goes beyond that.

.....Cotten
As Edison said it isn't failure, you learned another way that doesn't work. I've wondered about lapping with slightly concave soft rod and diamond paste. But I can't find my roundtuit n I'd rather do old Scouts anyway. I lap the sump check valves in Pre 48 Indians but they are easy to get to and I can lap both sides together.
Dusty

Post Sun Nov 20, 2016 1:48 pm

Posts: 3222
Location: Central Illinois, USA
DD!

Bubbles don't lie.
Lapping makes things worse because it widens the seat, instead of leaving a crisp line of interference, just like motor valves seal best with a narrow seat.

Unfortunately, preventing static oil seepage over a long time is much more difficult than sealing airflow in the dynamics of a running motor.

A round ball can never enjoy a perfect radiused seat, down to the molecular level of oil, unless the seat is a temporary, soft material, and then there is the issue of sealing beneath the seat.

I have a UL that I need to get out of the back room before cold weather; The owner rode it and was delighted, but balked over the sumping issue. Other things have been in my way, but since he rode it, it hasn't static sumped at all.

Evil.

....Cotten

Post Sun Nov 20, 2016 4:48 pm

Posts: 1120
Location: Ojo Caliente,NM,USA
Cotten,
The seat widening was why I suggested a concave lapping rod, so hopefully you would end up with a seat sorta like the rolled NASCAR seats. Where two circles intersect is by definition a single point of contact. And the incredibly even diamond lapping compound should be much better than the play ground sand they sell you in valve lapping compound.
Dusty

Post Mon Nov 21, 2016 8:29 am

Posts: 644
Location: Wisconsin, USA
I cut the sdeats with piloted 45 degree cutter and reduce the cut with a spot facing bit. Light lap with an evo pushrod end ball with 600 grit compound. It has always worked well for me.

Post Mon Nov 21, 2016 8:46 am

Posts: 3222
Location: Central Illinois, USA
DD!

I thought you meant concave to match the ball;
Convex would certainly be better thanb concave, but a lot more difficult.
Please remember that I found castings to vary on the concentricity of the cap threads to the seat, making a pilot hit-or-miss, unless it is only a flat grind.

And Kyle!
Because of the piloting issue, I found that putting any angle on it sank the seat significantly before there was complete contact to the ball, and then it still leaked. Believe me, I tried:
CHKCUTRS.jpg

Have you bubble-tested at 3-4psi?

....Cotten
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