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-   -   Sportster Crankcase Pressure / Engine Breathing / Wetsumping and Mods (http://xlforum.net/forums/showthread.php?t=2073932)

dieselvette 8th August 2019 05:52

I don't mean to argue and don't claim to have all the answers. I think you're all partly right, but something doesn't add up.

Before the last time I shut down my bike, I let it idle for at least 10 minutes and it was up to decent operating temp and had plenty of time to empty the sump (if there was any). Immediately drained the tank. After pulling the jugs and cam cover and oil pump, I went in the CC with a syringe and sucked out at least 10oz of oil. (I'm pretty sure I got the suction hose below the windage tray and got it all, but I still need to doublecheck that before re-assy.)

Dis-assembled the oil pump, looks perfect. Inspected all vents/lines/passages and everything checks out. Never had oil puking.

So I don't mean to be a smart a55 but please explain how there was oil left in the sump, even though there is "never" an accumulation of oil in the sump. I can't believe that there was 10oz of oil suspended in the CC at idle which all dropped to the bottom on shutdown.

I'm not really trying to diagnose my own bike (doesn't matter cause I'm upgrading many things anyway) but it would be interesting to understand this better and for posterity.

Bikeaholic 8th August 2019 06:23

Hi Gunner,
I hope i have not intruded on the current theme of conversation. As i am very interested in these posts/discussion.
In relation to the baffle plate in Cam cover... i mentioned in a previous post i have the baffle plate in the same place and almost identical to yours.
( with the deeper center to help limit splash ) you have in cam cover casing. My first attempt had too much oil puke but the second splash gaurd looked very similar to yours and worked much better than my first attempt. Also I have minimal drips/froth from end of Krank vent hose. ( but always some, a little more when high rpm ) I thought you would be all fine with the baffle plate as you had it. This is why i posted previously so you would not have to experiment too much. So i am a bit surprised and disappointed of the oil puke you had. It is a couple of years since i did mine. I do have some rise upwards in hose where it exits the cam fitting prior to the krankvent, maybe this aids in some drain back to camcase?
I do not have the fitting "flush on inner cam case", but screwed further inwards so not to encourage an easier oil escape as this will create a type of raised lip so oil stay around fitting rather than go in. I hope this make sense. I think you may have done this anyway. Just a thought! I not know why this appears to have more oil puke than mine?
Also there is a " Xl Vision Cam Cover by Figure Machine" on You Tube. People can view the oil response to cams etc whilst engine running. May be of some interest. Many may have seen this before.

Tomcatt 8th August 2019 14:43

Quote:

Originally Posted by dieselvette (Post 5768441)
So I don't mean to be a smart a55 but please explain how there was oil left in the sump, even though there is "never" an accumulation of oil in the sump. I can't believe that there was 10oz of oil suspended in the CC at idle which all dropped to the bottom on shutdown.

How high was the level in your oil tank? With the tank vented back to the cam chest you can be pumping oil back to the tank just to have it flow back into the engine thru the vent line.

60Gunner 8th August 2019 15:56

Quote:

Originally Posted by Tomcatt (Post 5768436)
I still think that what's needed is an oil pressure relief. At higher revs it would work like "the bypass" but would maintain adequate flow at low(er) revs. Have we come full circle yet?

Or you could buy a set of S&S cases that have better oil management.

The bypass mod Aaron posted about with the slow jet. Thought about trying this maybe using a smaller jet tho.
Or a pressure relief at about 30psi.

Tomcatt 8th August 2019 15:59

Quote:

Originally Posted by 60Gunner (Post 5768511)
This is what the mod Aaron posted about does with the slow jet. Thought about trying this maybe using a smaller jet tho.

That's "the bypass" I was referring to. An oil pressure relief will do the same but without hurting lower rpm flow.

60Gunner 8th August 2019 16:02

Yeah, I realized that when I read it again. A pressure relief at about 30psi would be ideal.

dieselvette 8th August 2019 22:38

Quote:

Originally Posted by Tomcatt (Post 5768498)
How high was the level in your oil tank? With the tank vented back to the cam chest you can be pumping oil back to the tank just to have it flow back into the engine thru the vent line.

Fair question. Honestly I don't remember checking it before draining, but I had checked it the day before after warming up and it was below half. (Granted, there may have been some in the sump then too). Not sure this would matter tho because that vent returns to cam chest, not CC. How would it end up in the bottom?

This makes me curious Has anyone ever checked how much oil fits in the tank, before it starts running down the vent, while on the kickstand? Is this even worth knowing since you should avoid running over 1/2 on the dipstick anyway?

bustert 9th August 2019 01:04

we know it will hold factory fill which i run all the time, ole wives tale on bag level is unfounded.
yes there will be a few ounces. there is oil cling to cases, pistons, jugs and bearing drain out from the wheels. dry sump does not mean no oil. guess what, if the oil in the cam case is high enough, guess where that goes, yep, same o same o.
yep, the crown is good, found some bottled in 1979.
getting back to the ironhead oiling schematic, those arrows are not oil being pushed up the wall, just depicting oil sling, probably mostly from pin exit.

60Gunner 9th August 2019 01:18

Quote:

Originally Posted by dieselvette (Post 5768608)
Fair question. Honestly I don't remember checking it before draining, but I had checked it the day before after warming up and it was below half. (Granted, there may have been some in the sump then too). Not sure this would matter tho because that vent returns to cam chest, not CC. How would it end up in the bottom?

This makes me curious Has anyone ever checked how much oil fits in the tank, before it starts running down the vent, while on the kickstand? Is this even worth knowing since you should avoid running over 1/2 on the dipstick anyway?

I don't think much oil ever travels in this line. It seemed dry to me when I pulled it off the cover. Just an after the fact observation now that I think about it a month later.

Hippysmack 9th August 2019 01:26

Quote:

Originally Posted by dieselvette (Post 5768441)
please explain how there was oil left in the sump,

bustert beat me to it.
When you shut down the engine, there is still oil in the rocker arms, heads, on top of the flywheel assembly and cam gears, cylinder walls, oil feed galley in the gearcase wall, cam bushings, least not forget the oil feed line to the oil pump.
Seepage from the feed line either past the spacer between feed and scavenge in the pump or past the check ball in the filter pad will gravity feed into the engine also.

Oil in the top of the feed galley is pressurized at the moment the engine is shut down and can also drain down through the piston squirters into the sump.

So yes, there should be oil left there.
If it's not, that's a bigger worry.


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