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

Folkie 10th August 2019 20:56

Quote:

Originally Posted by 60Gunner (Post 5769133)
So when they changed the pump in 07 they went back to less restrictive bolts?

No, that's not the case. The breather screws haven't changed between 2004 and 2020: # 3565.

dieselvette 10th August 2019 22:44

"You haven't installed smaller pistons so the fact that you still have a higher volume of pressure isn't affecting you now.
I think you improved the balance."

I know what you mean, but this seems misleading. 60Gunner had faulty stock umbrellas - nobody knows if new stock umbrellas would have worked just as good as his new breather setup. Like many, he made the choice to apply the best breather system he could come up with, and that's a perfectly reasonable thing to do.

Now I think a lot of people in the same circumstances could have done the same mods to the same bike, and said "the krankvent got me 5hp" and left it at that. And I know hippy is careful to sort through the bs, so we're thankful for that. And thankful that 60Gunner is straightforward about what he is or isn't seeing.

(Sorry if this post causes any drama, don't mean it that way)

Hippysmack 11th August 2019 00:04

No I think you're exactly right.
There hasn't been enough trial and error to conclude that the stock breathers just aren't up to the task.
We do have Aaron's testing that seems to uphold the fact that stock breathers are not the problem they are made out to be by the folks that have done the different mods.
But the folks have done the mods aren't getting that bad of results either.
That goes back to what I said that they are not necessarily better, just different.
But to people that have not been exposed to the arguments, they are easily lead astray by the ones that fault the OEM breathers.
And that is one of the things I've been looking into.... the truth.

60Gunner 11th August 2019 01:25

To add to that, if there is a difference, is it discernable. I've always said my problem could likely have been solved, satisfactorily at least, by replacing the stock breathers. I think they're more prone to failure and the plastic housing does warp. Not serviceable like the krankvent either.
That said, I have nothing to say the krankvent works better. I can say with a degree of certainty it lets less air back in.
I'd also have to say it certainly doesn't work worse.
Same with the location. If not for the oily discharge that could most likely be solved, the location doesn't seem to matter either way.
Even if I were to put new stock breathers in and remove the krankvent, in not sure the difference, if any, would be discernable. If it were, it would still be subjective to me and the feel of my motor which I AM very in tune with. Unless there was a blatant difference which I doubt.

I thought George had bigger breather bolts. But that wouldn't make sense since he's an 06 anyway.

Bottom line is it's my belief the stock system is adequate with room for improvement. If they fail, I think the krankvent is a better option than replacing with stock breathers based on the versatility of where it can be put and ease of service alone. I don't think anyone using it would say the stock ones are better.

What exactly was the purpose of the smaller breather bolt holes because from where I'm sitting it didn't work if it was to solve wetsumping. Hence the new pump route was taken. Plenty of people using bigger breather bolt holes with no adverse consequences apparently. Or is there?

What about those that had oil leaks become a thing of the past with the krankvent? Has everyone replaced faulty stock breathers or have some them replaced working stock breathers and have results like this?

dieselvette 11th August 2019 01:42

1 Attachment(s)
Quote:

Originally Posted by Hippysmack (Post 5768932)
Well, that's kind of the point.
I'd like to be able to prove instead of theorize.

Play around with this-
https://www.gates.com/us/en/resource...low-calculator

See attached example.

dieselvette 11th August 2019 01:53

Oil pump sump drain
 
1 Attachment(s)
Here is a picture of the new oil pump, installed. When I installed it, I primed it turning by hand without the pinion gear installed. In this way I could prime both the scavenge and the supply side really really good.

The picture shows the oil pooled up around the cone, where the cam sump intake is. This area has been sitting full of oil for over a week, with the cam cover OFF. During this time the oil tank was also partly filled with oil and all connected. I cannot prove if any seeped into the crankcase, as that was not empty to begin with, but there is no evidence of oil seeping out of the tank to anywhere and no puddle on the floor (that would have come out the top of the pump, due to the cam cover removed). So I think it proves that with a new pump, oil does not seep through the pump at all.

With the old pump, I will do the same test on the bench and report back in a few days with results.

dieselvette 11th August 2019 01:58

1 Attachment(s)
Here is a picture looking down the front cylinder hole. The oil level looks the same as it did a week ago. The circled metal part is the windage tray, so the oil level is not to the top edge of the tray, but it does cover the rest of it.

After taking the picture I sucked 6oz of oil that was all the more I could get. (If you recall from previous posts, this is in addition to the 10oz I removed earlier.)

So this shows that approx 6oz is all it takes to submerge most of the windage tray when on-level.

In theory if the engine is running, wind is pushing this oil towards the back, and the windage tray would probably not be submerged.

Hippysmack 11th August 2019 02:43

Quote:

Originally Posted by 60Gunner (Post 5769216)
What exactly was the purpose of the smaller breather bolt holes because from where I'm sitting it didn't work if it was to solve wetsumping. Hence the new pump route was taken. Plenty of people using bigger breather bolt holes with no adverse consequences apparently. Or is there?

What about those that had oil leaks become a thing of the past with the krankvent? Has everyone replaced faulty stock breathers or have some them replaced working stock breathers and have results like this?

Rewind.
It was one a several changes to the overall OEM revisions.
It was not the one thing to solve wet sumping.
People running bigger bolts on rubbermounts are also running extended vent lines (swapping one restriction for another).

The list of reasons people have oil leaks has never been nailed down to the fact of being the breathers.
Too many things were changed at the same time to ascertain what the main problem was.
Too many non checked variables there to make a determination.
For the most part, most have not gone into the detail we have on the subject.

Hippysmack 11th August 2019 02:55

Quote:

Originally Posted by dieselvette (Post 5769226)
Play around with this-
https://www.gates.com/us/en/resource...low-calculator

See attached example.

I can't.
I have no actual flow data to input.
The chart is going to be skewed even if we did have flow data due to the variable CC volume.
The calculator is designed to calculate steady air flow output which we don't have data for.
Nor do we have steady air flow output.
It also doesn't take into account the density of the air / mist which is also variable.
So I'm not sure what that would help us with. :(

Folkie 11th August 2019 03:04

Quote:

Originally Posted by Hippysmack (Post 5769239)
The list of reasons people have oil leaks …

I cant say I've ever had an oil leak.


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