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

Hippysmack 8th July 2019 06:37

They only use the cooling jets on 04 and Up though.
Rifled connecting rod, with different bearings or more feed pressure... or both?

Is there a different feed pressure requirement for IH bearings as opposed to Evo?
All needle bearings with different cages?

Don't know anything about skirt rings.
May help with piston rock but add more wear in the cylinder?

bustert 8th July 2019 15:41

i do not think hd flywheels are much diff functionally over the years, yes there are changes but the concept functionally the same.
the trunk lower rings are actually there to help prevent hot piston skirt from contacting the liner and actually help prevent wear. as engines tighten up and better oils came along, you see mfg getting away from the design, waukesha being one of them.
cage and bearing skate will be like a oil thread, never ending.

if you look at the law of averages, c/c pressure does settle out as a fairly even pressure, more so as rpm goes up.

Hippysmack 8th July 2019 17:16

I agree it should settle out pretty evenly.
That is optimal.
I'm just working on the non-optimal instances at the moment.
These non-optimal instances are the ones causing all the problems.
So the million dollar question is:
What does it take to make a non-optimal situation optimal?

edit:
I've added some pics of the 04 Up breather valve in post 10.
Thanks to 'Bored now' for the gracious pics of one cut open.

Bluto 8th July 2019 18:40

Breather valves and crankcase pressure are an issue on classic British twins too since they have 360 degree cranks. FWIW Mike's XS 650 sells a quality reed type breather valve for $23 that works well and lasts, popular in the Norton Commando world and am using one successfully on my 850. Also reduces oil leakage. Anyway don't know if they would work on a Sportster but maybe worth a try. Currently out of stock unfortunately but hopefully that will change or maybe they can be found elsewhere.

https://www.mikesxs.net/yamaha-xs650...valve-pcv.html

https://www.mikesxs.net/media/catalo...15-0677_01.jpg

Jollly Rogers 8th July 2019 19:54

Any idea what the dimensions are for this check valve?
Joe

Bluto 8th July 2019 20:02

Quote:

Originally Posted by Jollly Rogers (Post 5761232)
Any idea what the dimensions are for this check valve?
Joe

Not exactly, but here is a photo with a quarter coin for scale I took before I installed it...
hmm, now see that the one I bought a year or two back is a bit different from what the Mike's XS site shows currently...but would guess they are about the same size.

https://lh3.googleusercontent.com/Sd...800-no-tmp.jpg

bustert 8th July 2019 21:03

i do not believe there is an optimal and non optimal
hd never intended for fools to be burning up the roads with a street designed machine. it is a common issue through out all the design years. the issue creeps up with age and nothing stays new so you really cannot blame the machine, it is doing as intended.
we as riders can influence the out come, our choice and our crutch to bear.
why do not the honda 360* crank designs have issues. to be honest, i never owned a honda that had issues with c/c venting. i can only remember a friend with a honda cl90 that huffed and spewed oil and i directly attribute it to a evil dealer who drilled a hole where one should not be, the machine was fairly new, went into the shop for wreck damage to forks and came out running like shinola.
if you look at rice, the coalescer was way more than two chinchy rubber pieces that vent through a "S" channel. the mesh will make things worst.

Hippysmack 8th July 2019 22:48

Quote:

Originally Posted by bustert (Post 5761258)
i do not believe there is an optimal and non optimal
hd never intended for fools to be burning up the roads with a street designed machine.
it is a common issue through out all the design years. the issue creeps up with age and nothing stays new so you really cannot blame the machine, it is doing as intended.

That is the conclusion I have come to also.
Optimal means riding the bike as it was designed.
In that, non-optimal is when maintenance is required.
This, of course, also goes against conventional or maybe conceded thinking.

Quote:

Originally Posted by bustert (Post 5761258)
we as riders can influence the out come, our choice and our crutch to bear. ... the mesh will make things worst.

And that is where engine mods get into the mix.
Modifications to OEM engineering require respective engineering to make up.
And that defines the carpet under my feet at the moment.

That's what I thought about the mesh.
If you are wetsumping for whatever reason, more oil is gonna hit that mesh at once.
The outcome has to be obvious.
Look at the pic with the cut - off top.
There is an extra holding chamber in the middle for final separation of oil.
That chamber can't empty from what I see.

Quote:

Originally Posted by Bluto (Post 5761233)
Not exactly, but here is a photo with a quarter coin for scale I took before I installed it...

I would like to see some specs for those.
None published...

Bluto 9th July 2019 04:25

Doubt any specs are available for those but do know many with classic British bikes have been happy with the Mikes XS PCV (or maybe originally for EGR??) valve, have yet to see a negative review.

Hippysmack 9th July 2019 04:38

I haven't done a lot of research for construction or function yet on breathers/reed valves.
But there was a member here (bunny32) that was doing some testing on external breathers.
Granted, he was doing R&D to sell them.
Maybe why it says 'banned' under his screen name.
But, he had some interesting data on the subject.
I am unclear if his data was good for sportsters as he was mainly testing brit bikes I think.
That was in Deimus' first vent mod thread:
http://xlforum.net/forums/showthread.php?t=67658

There are differences in different aftermarket breathers so I would like to know what they are.


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