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

Hippysmack 3rd November 2019 01:53

Iree can you elaborate on that?
The only gas law I know is buy low and ride high. :o

60Gunner 3rd November 2019 01:14

Cylinders going up while others are going down in a car engine. 2 going up and down at nearly same time in a v-twin.

Hippysmack 3rd November 2019 03:09

I'd think it would be the high rev swing-ability of Sportster pressure that the spring and diaphragm can't keep up with.
I don't know for sure but yeah, the pressure should be more stable in car motors.

I changed the breathers today and found that a fiber washer on the front box was toast.
The middle broke out, got soft and bunched up around the hole and it now looked more like a smaller thicker washer.
The small piece feels much softer than the easily breakable fiber washer that I installed.
Maybe it bunched up into the hole. There was no oil around the bolt from the outside.
These have been re-used several times before, replaced them all today.
http://www.sportsterpedia.com/lib/ex...hippysmack.jpg

The umbrellas looked good to me.
The front was more soft than the rear but both were still flimsy.
It turns out I only replaced the front the last time I was in there, it had 'James' written on it and the other didn't.
But I replaced them both today anyway.

rocketmangb 3rd November 2019 03:22

Update the bolts and washers to the '08 and up style I think

Hippysmack 3rd November 2019 03:25

What's the difference?

rocketmangb 3rd November 2019 03:25

2486 and 6589A

Hippysmack 3rd November 2019 03:26

What if I just toss the fiber and use the copper?
Can't find a pic of the newer style bolts at the moment.

Hippysmack 3rd November 2019 03:46

I'll look them up.
Thanks for the PNs.

rocketmangb 3rd November 2019 03:50

Washer is called a Stat O Seal

Hippysmack 3rd November 2019 03:59

Aaaaahhh,
Now I see the difference.
They look like dowdy washers.
I'll have to wait for those but it looks like a better seal.
I'll put it on my list.

https://www.jegs.com/images/photos/3...361-178003.jpg

harley506d 3rd November 2019 08:20

Those washers look the same as they use on the brake lines. Much better than copper.

Jollly Rogers 3rd November 2019 12:34

GM used those washers on oil pan drain plugs in the 90s and 2000s. Then they added a groove in the washer head of the bolt for a modified o-ring. The pictured seal washers can get torn up by over torquing and uneven surfaces they contact. Burrs where the surface is tapped for threads should be checked for and removed.
Joe

bustert 3rd November 2019 14:59

although could be related to laws, the orifice choice was based off displacement volume to control pulsation and to have a minimal effect on the reading.
it would be diff for diff engines.
if it was just flow, a "SONY" flow calculator would do the trick.
https://petersoninst.com/wp-content/.../12/sonney.jpg

Hippysmack 4th November 2019 01:21

Today's testing with the new umbrellas showed about a 3-1/4" reduction in vacuum at idle.
edit:
That's in the left leg (6-1/2" of water total).

The engine seems to lope a little better at idle although there wasn't a seat of the pants difference on the road.

I tested with the A/C off also through 5000 and there wasn't any difference between having it on or having it off.

I moved the timing both ways while testing and there was no difference in the readings.

But I'm now going to positive pressure around 4200 rpm.
At both 1000 and 2000 RPM, there was not a fast changing variance in the measurement (as was in the previous test mostly at idle).
The variant level is still about a 1/4" up and down but it rises and falls slower now.

The spitting back now begins around 4100-4200 in the shop. Coincidently that's about where I'm going to positive now.
I don't notice this at all on the road. I haven't touched the carb yet.
I call it spitting back but there is a noticeable vibration and a change in engine harmonics when this happens.
There doesn't seem to be any engine drag as I can roll the throttle over it and it kind of goes away.

I forgot to pull the oil cap today. :doh

1000 RPM:
http://www.sportsterpedia.com/lib/ex...hippysmack.jpg

2000 RPM:
[IMG]http://www.sportsterpedia.com/lib/ex...hippysmack.jpg[/IMG]

3000 RPM:
http://www.sportsterpedia.com/lib/ex...hippysmack.jpg

4000 RPM:
http://www.sportsterpedia.com/lib/ex...hippysmack.jpg

5000 RPM:
http://www.sportsterpedia.com/lib/ex...hippysmack.jpg

1000 RPM with the A/C removed:
http://www.sportsterpedia.com/lib/ex...hippysmack.jpg

There is condensation and light oil mist accumulated at the bolts.
But none of this is in the A/C and no oil puking.

http://www.sportsterpedia.com/lib/ex...hippysmack.jpg

edit:
I'll add also I've had no noticeable signs of wetsumping or oil puking out the breathers even before any of this testing began.
This is the first time I've had the A/C off during testing or paid attention to the bolts.
So the oil accumulation coming mainly from the rear bolt may have been from the rear umbrella before I changed them.
It was a little stiffer than the front but still would bend over. Just not as much as the front would.
The front was just as flimsy as a new one.

Hippysmack 4th November 2019 01:43

60Gunner, I'd be real curious where you would be about now on a slack tube.

Hippysmack 4th November 2019 02:44

If I built a 12" tube box, mounted it by behind the windshield and throttled the feed to it, would the wind create too much pressure on the top of the tube for the readings to be measured?
Would throttling the feed have any change on height?

bustert 4th November 2019 15:05

i do not think the fluttering is related
on occasion, mine will do the same thing
i attribute it to cv flutter.
it occurs mostly when i start up and roll before the temps come up. i am geared diff so mine comes in the 2.5 > 3.5 rpm range and is very noticeable but i can change rpm and it goes away and after awhile it goes away. i also run on the rich side to avoid a high speed lean out so mixture plays a part also. if the machine is running normal temps, better hold on.

bustert 4th November 2019 15:12

if you have a fly on your dash board and you are doing 60 mph and the fly decides to lift off, why does he not get slammed into the rear window?

60Gunner 4th November 2019 16:20

Quote:

Originally Posted by Hippysmack (Post 5786276)
60Gunner, I'd be real curious where you would be about now on a slack tube.

*Sigh* I knew that was coming sooner or later. :p
My idle was noticeably better. I noticed this immediately on start up the very first time. It also revved easier, smoother.
This was just plugging it in the hose right after the horseshoe too. I had previously done away with the hoses and clogged filter and ran open bolts a few days. When the krankvent came I put the hoses back on with just a 3" length going to it and nothing after. This difference was quite noticeable.

Hippysmack 4th November 2019 17:02

Quote:

Originally Posted by 60Gunner (Post 5786384)
*Sigh* I knew that was coming sooner or later. :p
My idle was noticeably better. I noticed this immediately on start up the very first time. It also revved easier, smoother.
This was just plugging it in the hose right after the horseshoe too. I had previously done away with the hoses and clogged filter and ran open bolts a few days. When the krankvent came I put the hoses back on with just a 3" length going to it and nothing after. This difference was quite noticeable.

I'm thinking the rear umbrella on mine wasn't opening far enough.
Or maybe it was stuck closed seeing how so little force is exerted outward.
It wasn't hard though.....
For whatever reason, I had more vacuum than with new umbrellas.
Your umbrella doesn't allow any atmosphere to enter, outside of closing time.
I was just wondering how much vacuum you had.

Hippysmack 4th November 2019 17:17

Quote:

Originally Posted by bustert (Post 5786371)
i do not think the fluttering is related
on occasion, mine will do the same thing

I think of the second test as first since the engine was warmed first.
Then, I was getting the condition around 5500, which is about the point I would've went positive.
Now it's around 4200 which is about where I went positive.
So it does make me wonder if there is a correlation.
I'll do some testing tweaking the carb next.
I wonder if manipulating the vacuum on throttle side would change that.
I know it'll remove or diminish the MAP. But timing didn't seem to affect the readings.

Quote:

Originally Posted by bustert (Post 5786372)
if you have a fly on your dash board and you are doing 60 mph and the fly decides to lift off, why does he not get slammed into the rear window?

Yeah but you have four walls of windows, a ceiling and a floor. :)

I may try that. I need to mod my old oil cap and test the oil tank first.

60Gunner 4th November 2019 23:47

Quote:

Originally Posted by Hippysmack (Post 5786394)
I'm thinking the rear umbrella on mine wasn't opening far enough.
Or maybe it was stuck closed seeing how so little force is exerted outward.
It wasn't hard though.....
For whatever reason, I had more vacuum than with new umbrellas.
Your umbrella doesn't allow any atmosphere to enter, outside of closing time.
I was just wondering how much vacuum you had.

So basically I'd have to make one of these dohickeys to find out. I'm curious, just not sure I'm that curious. But let me see what I have laying around to construct one.

Hippysmack 5th November 2019 01:08

Well...... that was the general persuasive direction of the suggestion. :D

bustert and I are representing rigid mounts, S models in specific.
If we could get you and FourSpeed doing some testing and maybe a couple ironheads, we'd have at least some patterns to pull from.
Given each engine is different, I bet we'll see some similarities too. :)

I'm particularly interested in the breathing system on rubbermounts as those with engine upgrades seem to have more problems than without.

60Gunner 5th November 2019 03:00

I'll get working on it then for the team. ;p
Might take me a few days to get on it tho.

bustert 5th November 2019 15:38

i bet there would be
i would also venture to say the iron vents way more, irrespective of displacement.
somewhere, i have the degree of rotation vs open rotary valve which is fixed, the rubber thingy is left up to do what it wants.
secondly, the iron cam chest is open to atmospheric environment
that said, the volume of the internal engine is way less.

60Gunner 5th November 2019 15:54

I was wondering what difference there would be with my larger displacement tho its not that much larger.

As for those washers, copper is better. Especially on brake lines. I bought the washers Rocketman posted but not the bolts. Need the bolts too I think. I tried with regular 16pt. bolts and the heads bend the metal as they start going thru them fairly easy. Heads are too small.

Hippysmack 5th November 2019 16:52

Quote:

Originally Posted by bustert (Post 5786529)
secondly, the iron cam chest is open to atmospheric environment
that said, the volume of the internal engine is way less.

Is the 76< with the timed breather open to atmosphere?
http://www.sportsterpedia.com/lib/ex...by_dr_dick.jpg

http://www.sportsterpedia.com/lib/ex...by_dr_dick.jpg

The 77-78 foo foo is supposed to be a one way breather although I'm unsure of it's construction.
http://www.sportsterpedia.com/lib/ex..._by_hopper.jpg

http://www.sportsterpedia.com/lib/ex..._by_hopper.jpg

79-E1982 had the reed valve.
Never put optical nerves on one but is it a true one way?

http://www.sportsterpedia.com/lib/ex...y_tobybott.jpg

http://www.sportsterpedia.com/lib/ex...by_lodkolv.jpg

L82-90 had the cam chest mounted umbrella valve.
http://www.sportsterpedia.com/lib/ex...y_spamer80.jpg

http://www.sportsterpedia.com/lib/ex...y_bryan350.jpg

Hippysmack 5th November 2019 17:10

Quote:

Originally Posted by 60Gunner (Post 5786531)
I tried with regular 16pt. bolts and the heads bend the metal as they start going thru them fairly easy. Heads are too small.

I figured I'd try to find a metered difference with the fiber and copper washers also.

Maybe if you used a steel washer over those type washers, it'd pull them in equally?


Quote:

Originally Posted by Jollly Rogers (Post 5786139)
The pictured seal washers can get torn up by over torquing and uneven surfaces they contact. Burrs where the surface is tapped for threads should be checked for and removed.
Joe

I pulled the fiber washers to 120 in. lbs. starting in increments of 20 in sequence.
But I did notice, just outside the sealing surface, some chrome pitting in the bolt bosses.
Something to keep in the back of my head.

bustert 5th November 2019 19:33

i am pretty sure there is some slippage through the clearances but when the windows are closed. cam chest down tube is open to the world.

how about this timer
https://i.imgur.com/8hH31E0.jpg

who cares what position it is in when installed

60Gunner 5th November 2019 19:43

Quote:

Originally Posted by Hippysmack (Post 5786541)
I figured I'd try to find a metered difference with the fiber and copper washers also.

Maybe if you used a steel washer over those type washers, it'd pull them in equally?

This is I've done and it works great. Not sure what the new bolts that go with the washers look like.

Hippysmack 5th November 2019 20:21

What's that go on bustert?
I'm still a little fuzzy on timed breathers.


Before the new umbrellas, I lost 3-3/4" (7-1/2" WC) and the engine died when removing the oil cap.
I checked today and I still lost 2-1/4" (4-1/2" WC) when removing the cap.
But, I only lost a slight pitch in the engine and not a noticeable amount on the tach.
No frothing in the oil tank now with the cap removed at idle.
So it does look like the rear umbrella was on the way out.

http://www.sportsterpedia.com/lib/ex...hippysmack.jpg

I had (previous to any testing) set the A/F mixture by the Idle Drop Method:
http://www.sportsterpedia.com/doku.p...rop_method_idm

Today I moved the mix to and fro and found no difference on the slack tube.

edit:
I tried to get to 6000 while testing in the shop and it won't do it.
But on the road, easy peasy.
Do I need to go back into the carb?

Hippysmack 6th November 2019 03:04

Summaries from Slack Tube Testing
 
I'll update this post as I go to keep all this info in one place.


A. Before changing to new umbrellas;
1. The rear umbrella was more stiff than the front one which was 'like new'.
2. I pulled the oil cap off at hot idle and the engine stumbled or died.
There was oil frothing in the oil tank when I pulled the cap off.
The frothing got less when the cap was 'slightly' off.
It didn't have any affect pulling the cap at cold idle.
3. There are app. 1/4" fluctuations in the pressure readings at 1000 and 2000 RPM.
The fluctuations are relative quick changing.

B. After changing to new umbrellas;
1. The engine loped a little better.
2. There was no noticable change in RPM with the oil cap removed.
3. There was no frothing of oil in the tank with the cap removed.
4. Engine sounds / lopes better with new umbrellas.
5. Residual vacuum was decreased with new umbrellas across the RPM range.
6. The engine flipped over to positive pressure at a lower RPM.
7. There was less gap between the pressure changes from 1000 and 2000 RPM.
8. Fluctuations of pressure at 1000-2000 RPM are much slower.

C. After restricting both breather bolts to 1/8" openings;
1. The smaller bolt holes actually reduced vacuum.
2. They also offer more control of CC pressure throughout the RPM range by creating lower pressure swings.

Other testing:
1. The air/fuel mixture did not have an affect on CC pressure.
2. There was no difference in pressure with the air cleaner on or off during testing.
3. Timing changes did not have an affect on CC pressure.

Other Notes:
There was no oil spewing / puking out the A/C before or after changing the umbrellas.
There was no extra drag on the motor before or after changing the umbrellas.

bustert 6th November 2019 14:11

how was the throttle acting at the 6k shop run?
6k on a free wheeling engine is diff with one that has a load.
was it 4 cycling (blubbering)
or if you backed down a tad, it would stabilize out?

Hippysmack 6th November 2019 16:00

I guess blubbering would be a good way to explain it but it seems to be RPM related.
It originally didn't start until around 5500, now just higher than 4000.
I back down from 4100 and it stops. I move past there and it stops until I get around 5500.
I think I'll recheck the float level.
I have the longer aftermarket float valve in it and it was difficult to set.
I had to suck on the inlet hose slightly to feel when the valve actually closed then set the float based on that or it'd leak.

bustert 6th November 2019 22:37

sounds like it is going rich, hummm which is funny because i run a 45/200 setup which is on the rich side
still have the vac petcock? i gutted mine so i would not pinch off on wot
i could have pulled it to 7k but no one rides there.

Hippysmack 7th November 2019 00:15

Yes, vacuum petcock. I don't think the petcock is a problem but I'll keep it in mind.
I decided to go ahead and reduce the breather bolts and that went OK except my memory went South on the 04-up hole size. :doh
I drilled 1/8" holes instead of 1/16".
But, it's still a restriction. The new assembly doesn't hinder the A/C.

For lack of having fine thread 5/16” bolts, course thread SS (5/16“x18) bolts were re-threaded to 5/16”x24. This works fine and re-threads easily.
But it's easier to go and buy the correct bolts.

http://www.sportsterpedia.com/lib/ex...hippysmack.jpg

The holding block was needed to keep the bolt straight while boring a hole through it.
You could use a block of wood, plastic or steel. The hole drilled was .2720“ and tapped 5/16”x24.

http://www.sportsterpedia.com/lib/ex...hippysmack.jpg

Each bolt was screwed into the hole, corner to corner lines drawn across the head to find center and the center punched to keep the bit from wandering.

http://www.sportsterpedia.com/lib/ex...hippysmack.jpg

An O-ring was added under the head to seal off the original hole.
The factory threads were chased with a 5/16“x24 tap to straighten warpage and clean the threads for the new bolts to be inserted.
Normally, marking center on both ends and sending the drill bit in just over half way from each end will make a more straight thru hole.
But this just being a test, the hole was drilled thru from one side.
The hole ended up off center in the thru end but this is not a critical point in this application.

So now, at least I'll get to see what affect smaller holes has inside.
I may re-drill more bolts to 1/16" if this shows a reduction.

http://www.sportsterpedia.com/lib/ex...hippysmack.jpg

http://www.sportsterpedia.com/lib/ex...hippysmack.jpg

http://www.sportsterpedia.com/lib/ex...hippysmack.jpg

http://www.sportsterpedia.com/lib/ex...hippysmack.jpg

60Gunner 7th November 2019 04:06

Not sure what difference it actually makes but shouldn't the exit holes be bigger?

Hippysmack 7th November 2019 04:25

I figured I'd just see if the restricted hole itself has an affect on pressure on the inside and if so how much.
I realize the restricted hole is on the inside end of the newer bolts.
I just want to see where I'm at here.
I have limited equipment now. If I still had access to the machine shop at the university, I'd just make some.
I could try to reverse these but I'm not sure if it'd make a whole lot of difference past the restriction anyway.
And given there will be a hose on the end of the vents later, not sure if flipping them is important, but it may be.


I don't plan on using this setup for anything else other than testing.
I don't have 04 breather bolts that I can use although I've been looking at some on Ebay.
That would probably make it easier for me to upgrade from.
Depending on what I come up with on the slack tube from where I'm at now, I may look into getting some 04 ones.
I'm still debating on how I want to run vent lines.

And yes, debating the Deimus mod. :hidechai

60Gunner 7th November 2019 04:34

I was going to say, vent from the cam chest. ;p

Hippysmack 7th November 2019 04:51

Well, in order to bring this little experiment full circle, I'm gonna have to eventually test cam chest venting also.
I've started from OEM breathing, then I'll go to external lines, then external breathing all from the heads.
Then I'll go to cam chest breathing.

We've done the theories and now the natural progression is hands on.
Thanks again to bustert for introducing me to the slack tube.

FourSpeed, if you're still reading this, is there a soft rubber sheet that can be purchased, cut round with a bolt run thru the center and a small washer underneath that would suffice for a replacement in the 86-90 baffle tube?


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