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

Hippysmack 3rd August 2019 21:39

:laugh
I've gotten 4 or 5 installs with this rubber so I got my money's worth out of it.
I was going to use my spare one this time but it turned out to be the wrong one. :(
It's all part of it.
Besides, I've been putting off replacing the inlet so I could ride.

dieselvette 3rd August 2019 23:45

Quote:

Originally Posted by Hippysmack (Post 5767415)
Big Swamp said the only HD that had it in stock was in Texas and California.
So I ordered 3 from them.

Yeah it's pretty surprising the lack of carb parts in stock around the country. I needed an idle mixture screw, and was even willing to buy a whole carb of any kind new or used, and do you think I could find one?

Hippysmack 4th August 2019 00:08

Top it all off, the guy at HD recommended I go see Doc. (well known in these parts).
But he hates Sportsters.
I didn't want deal with him.
The guy said I'll end up with the only 2 spares in the Southeast!
That didn't make me feel so good either.

bustert 4th August 2019 21:51

here are the slack tube readings at not load, will stand to reason that pressure will be diff with load due to higher fuel burn and pressures
1000 rpm

https://i.imgur.com/CJdK1fT.jpg

2000 rpm

https://i.imgur.com/2otJXgr.jpg

3000 rpm

https://i.imgur.com/1HR72N9.jpg

4000 rpm

https://i.imgur.com/3QPZacD.jpg

5000 rpm

https://i.imgur.com/bf50kRr.jpg

6000 rpm

https://i.imgur.com/1wSc033.jpg

notice that there is a transition to a positive pressure above the 5k mark, not a surprise.
we could speculate anything from over-running vent capacity to time factors. the numbers are subjective to ambient to elevation.
however, we could use it as a tool to determine engine wear like they do on a diesel engine. all-in-all operated as hd intended within the intended most used rpm range
you were right, i expected to see lower numbers.
this would be inches of water and you can convert to psig but remember, we have to add both sides so a 15 on one side with a 15 on the other would be 30".

Hippysmack 4th August 2019 23:05

Holy Smokes!!
That's pretty much how my truck reacts.
bustert, can you post pics of your rig and fittings?
Where do I get the slack tube?

edit:
Found some cheap used ones on Ebay.
Any issues with a used one?

dieselvette 5th August 2019 01:20

Quote:

Originally Posted by bustert (Post 5767677)
here are the slack tube readings at not load, will stand to reason that pressure will be diff with load due to higher fuel burn and pressures
notice that there is a transition to a positive pressure above the 5k mark, not a surprise.
we could speculate anything from over-running vent capacity to time factors. the numbers are subjective to ambient to elevation.
however, we could use it as a tool to determine engine wear like they do on a diesel engine. all-in-all operated as hd intended within the intended most used rpm range
you were right, i expected to see lower numbers.
this would be inches of water and you can convert to psig but remember, we have to add both sides so a 15 on one side with a 15 on the other would be 30".

Perfect! That's exactly what I intended to do once I get mine together - didn't bother suggesting because it seemed to complicated to explain - but actually not that hard to set up was it?

Keep in mind with the readings - obviously the overall flow is an accurate reading - but by adding the length of tubing to get to the flowmeter etc, it changes the dynamics of the umbrella valve etc - I'm just saying it's not a good method for testing your breather setup, but a great method for seeing what the flows and pressures are as long as you keep in mind it tests your engine and not your breathers.

Hippysmack 5th August 2019 02:01

I agree there will many variables between our engines, locations and rig / setup.
But it's just like using a caliper for measuring.
As long as you measure every piece with the same one, it doesn't matter if yours doesn't match mine.
The slack tube readings will be relevant to that certain engine with that certain rig.
It can go in the tool box for analysis at any time.

bustert 5th August 2019 03:14

actually, you can make your own slack tube with plastic tubing and a tape measure. the one i used is a dwyers unit.
what is surprising is how stable the reading is. this being the case, a regular vac tester gauge could be used while riding, that way, load factor could be observed. if one could set up a camera on the gauge and then run the machine through the paces, a lot of info is available.
now all said and done, my machine has altered breather, altered cam timing and andrews cams n4's.
however, this is all top side so what effects does it hold for under the piston???? since the reading is from the timing plug, the breathers were fully functional.
the only issue was needing a needle valve to start off with, my first slack gauge was too small so it would have sucked the water into the flywheel compartment but the larger tube seemed to handle it in stride.

Hippysmack 5th August 2019 04:59

I haven't tried a vac gauge on the breathers.
I have tried it on the carb but it was very erratic as I assumed it would be at the timing plug.
I may try it though.

Shouldn't the liquid damper the hammer some?
I'd have to go back thru, but I assume you're using a bolt with a hole tapped in it with a 3/8" hose barb?
It looks like 2 fittings on top of the Dwyers unit, one in, one to atmosphere?

DIY slack tube (home use):
One long hose attached to the barb, length and looped at the bottom?
Apparatus attached to a piece of plywood with the line looped around a wooden ruler?

Why does the Dwyer only take green colored liquid?
Any special viscosity?

What needle valve and what learning curve to keep the liquid from surging back?
Picks of your fittings?
Restrictions needed?

Hippysmack 5th August 2019 05:09

Tomcatt, 60Gunner,
Is this a decent representation of the Hayden breather?
I'm assuming the spacer is under the umbrella as shown?
http://sportsterpedia.com/lib/exe/fe...hippysmack.jpg


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