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  #31  
Old 29th December 2015
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To the OP, can you blow air through the vent hole into the engine? If so then your umbrella valves need replaced. That you are oiling your filter every 9k is such a small amount that I wouldn't worry about it. Mine at 38k was dripping after 150 miles and after umbrellas gets around 400 miles before I pop the K+N off to wipe out the S/E base plate.

I also drilled out the small bolt ports to 3/16" to help the crank case exhale better with my blow by issues. It has worked out pretty well. Per the venting to atmosphere, it just makes a mess on the bike somewhere or on the ground when it get's parked. Been there, done that.

Umbrellas took about an hour to swap out and were under $30 for the pair. The module has a little foam air cleaner under the diaphragm to help separate the oil from the air.
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  #32  
Old 29th December 2015
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Thank you ASW: Was able to get a great deal on a new 883 5 speed so I was doing some break in miles to check for assembly problems from the factory and to see if it was basically sound when I look down after parking the bike and there is maybe an ounce of engine oil on the gear case. Called the Dealer as I figured the motor was about to blow and says *they all do that, very common*. This was at 500-1000 miles.
IMO the real problem is that the oil breather bolts are lower than the highest points oil reaches in the engine- this is just asking for trouble. So I remove the rocker boxes and inspect. Lots of casting flash- clean this up- reassemble- and it does it again though not so bad. Drips *less* but does put a lot of oil on the air-cleaner element. Since I was planning a performance build to 1200 with real good stuff I worked out a permanent fix.
***
Dyno tests are very good data collectors but they are very brief so I do not expect that you will get a crankcase overpressure in a short period of time but they seem to build pressure in continuous running at speed on open roads. In stop and go the pressure may return to normal. I think this because I blew a rocker cover gasket out on the highway on my Buell. I believe this had to be from internal pressure. I will not be riding around looking for oil pressure or crankcase pressure leaks and I full accept the HP results you have from the Dyno and thanks for posting them.
***
A pro HD racer told me there was no HP diff between single fire ignition and the old dual fire system and I believe that was correct also from the dyno but the engines run more smoothly on the road with SF in my view, idle batter and quit less. I think that crankcase overpressure/ air spring effects are cumulative but most races are very short so it is not an issue.
***
Thanks to Dudley Perkins HD for quickly replacing the rocker box gaskets.
***
So maybe I overdo things ;-). This is why I like using the top R box for future venting as oil liquids cannot rise that high and that will solve the biggest part of the problem. On the 5 speed solid mount engines I like to cut the excess metal from the cam case cover to get better access to the oil pump and it is easy to tap into the side of the case to the left of the rear exhaust cam. Then with plugged breather bolts, better replaced, your high flow air cleaner element no longer looks like one from an old truck.
***
ASW has me thinking that we need a volunteer to plug the venting and install a pressure gauge at a convenient place and see how high that goes after 2 hours at 85 mph.
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  #33  
Old 29th December 2015
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Quote:
Originally Posted by bustert View Post
way interesting hammer. I can understand a high oil content in the vapors but from what I see is mostly water unless the engine is toast. I wonder why it shows on the dyno? on my 440, I used holley water injection system and it was a definitely a plus, but it was a controlled system. any ideas?
as a side note, I have seen commercial inductions so gummed up with blow-by residue it had to effect it.
Blow-by is fundamentally just exhaust that went past the rings instead of out the exhaust port. It's depleted of oxygen, it's hot, and it picks up moisture and oil in it's travels through the crankcase and into your intake tract. So it's displacing oxygen in the intake charge that would otherwise contribute to combustion. It also heats the intake charge which contributes to detonation. It's just a bad thing all the way around, robbing power, causing detonation, and contributing to carbon build-up. Well worth it to remove it from the intake tract and vent it to the atmosphere or exhaust instead, in my opinion.
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  #34  
Old 29th December 2015
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Quote:
Originally Posted by 69xlch5213 View Post
Thank you ASW: Was able to get a great deal on a new 883 5 speed so I was doing some break in miles to check for assembly problems from the factory and to see if it was basically sound when I look down after parking the bike and there is maybe an ounce of engine oil on the gear case. Called the Dealer as I figured the motor was about to blow and says *they all do that, very common*. This was at 500-1000 miles.
IMO the real problem is that the oil breather bolts are lower than the highest points oil reaches in the engine- this is just asking for trouble. So I remove the rocker boxes and inspect. Lots of casting flash- clean this up- reassemble- and it does it again though not so bad. Drips *less* but does put a lot of oil on the air-cleaner element. Since I was planning a performance build to 1200 with real good stuff I worked out a permanent fix.
***
Dyno tests are very good data collectors but they are very brief so I do not expect that you will get a crankcase overpressure in a short period of time but they seem to build pressure in continuous running at speed on open roads. In stop and go the pressure may return to normal. I think this because I blew a rocker cover gasket out on the highway on my Buell. I believe this had to be from internal pressure. I will not be riding around looking for oil pressure or crankcase pressure leaks and I full accept the HP results you have from the Dyno and thanks for posting them.
***
A pro HD racer told me there was no HP diff between single fire ignition and the old dual fire system and I believe that was correct also from the dyno but the engines run more smoothly on the road with SF in my view, idle batter and quit less. I think that crankcase overpressure/ air spring effects are cumulative but most races are very short so it is not an issue.
***
Thanks to Dudley Perkins HD for quickly replacing the rocker box gaskets.
***
So maybe I overdo things ;-). This is why I like using the top R box for future venting as oil liquids cannot rise that high and that will solve the biggest part of the problem. On the 5 speed solid mount engines I like to cut the excess metal from the cam case cover to get better access to the oil pump and it is easy to tap into the side of the case to the left of the rear exhaust cam. Then with plugged breather bolts, better replaced, your high flow air cleaner element no longer looks like one from an old truck.
***
ASW has me thinking that we need a volunteer to plug the venting and install a pressure gauge at a convenient place and see how high that goes after 2 hours at 85 mph.
You have some really different theories, and that's fine, and I sure like to think I keep an open mind and can still learn things. I think it would be terrific if you could gather some data to support your views and I'm certainly open to having my mind changed.

Let me just repost something I originally posted in early April 2002. You might find this interesting reading. It was a long time ago, sure, but as far as I know, the laws of physics remain the same

Quote:
This page is to share some dyno testing of using the timing plug location for an additional crankcase vent.

First, a little background. In the stock configuration, the crankcase vents through a pair of "umbrella" valves, which are essentially check valves. There is no air inlet into the motor. As I understand it, the idea is that as the pistons come down the first time and the crankcase air is expelled, the air is forced out through the umbrella valves. But when the pistons go back up, the umbrella valves block the inflow of air, causing a slight vacuum in the crankcase. The next time the pistons come down, crankcase pressure will return to atmospheric. If no air is allowed into the motor, the crankcase will cycle between a vacuum (pistons up) and atmospheric (pistons down).

However, some air is actually allowed to enter, primarily in the form of blow-by that escapes the combustion chamber past the rings. Therefore, in the stock design, there is a small net outflow. The amount will vary with the condition of the motor.

Properly functioning umbrella valves therefore serve the purpose of significantly reducing the breather capacity requirement while also minimizing crankcase pressure. Excessive airflow & oil discharge through the breathers can be caused by malfunctioning umbrella valves that are allowing air into the motor.

For this test, an additional vent was added at the timing plug hole. No check valve was installed on this vent. Therefore, the crankcase is being allowed to pull in air as the pistons go up. This is fundamentally changes the engine's venting design.

Some people feel that allowing the engine to both inhale and exhale in this manner reduces crankcase pressure. Several people cite a "seat of the pants" improvement in performance. The purpose of this test was to determine if there actually is a performance improvement from this change to the venting system.




This is the fitting arrangement that was used. The first fitting is a 3/8" flare to 1/4" fpt fitting. The thread on the 3/8 flare side matches the thread in the timing plug hole. Attached to that fitting is a 1/4" mpt to 3/8" hose barb fitting. Two feet of 3/8" i.d. hose was attached here.




Here's a picture of the fitting and hose as installed on the bike.



And here's a picture of the bike on the dyno, a near stock 1999 M2.

Okay, on to the results. Lots and lots of dyno pulls were performed in each configuration, and the configuration was switched back and forth a few times. Dyno results are not 100% repeatable, and as such, I'll present a range of results for each configuration, as well as a comparison of the best pulls.




These are the 10 best pulls from the stock configuration.





These are the 10 best pulls from the timing plug vent configuration.





This is the best stock pull and the best timing plug vent pull. As you can see, the difference is within the repeatability of the measurement. If a person *had* to declare a winner, the results with the stock setup would seem to have a little edge, both in the "best" results and just looking at the average of the 10 best results. But I'd be careful doing that, you could be looking at normal variation.

Observations: I was surprised at how little air movement there was at the end of the hose. When a motor is started with nothing screwed into the timing plug, there's a massive inhalation and exhalation evident. But apparently, necking it down to a 3/8" hole and connecting 2 feet of hose adds a pretty significant restriction. Air flow was nowhere near what I expected. Unfortunately, getting a 7/16" or 1/2" hose into that area would be problematic, space is tight. Plus, a fitting with the correct thread and a 7/16" or 1/2" hole may not be available.

Another surprise was just how easy it was to plug the hose with my finger, and how it felt when I did. The pressure was not great.
In addition to the above, I also did a bunch of testing of the aftermarket breather check valves from Spyke and Hayden, and even did some experiments with vacuum pumps and the like. Did some magazine articles here and there at the time. The motor was remarkably insensitive to anything I did with the breathers. Like I said, the only thing I could get to show up on the dyno sheet at all was the removing of the blow-by from the intake tract.

I also did a bunch of single fire testing, but that's another subject.

Last edited by aswracing; 29th December 2015 at 23:53..
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  #35  
Old 29th December 2015
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Quote:
Originally Posted by aswracing View Post
Blow-by is fundamentally just exhaust that went past the rings instead of out the exhaust port. It's depleted of oxygen, it's hot, and it picks up moisture and oil in it's travels through the crankcase and into your intake tract. So it's displacing oxygen in the intake charge that would otherwise contribute to combustion. It also heats the intake charge which contributes to detonation. It's just a bad thing all the way around, robbing power, causing detonation, and contributing to carbon build-up. Well worth it to remove it from the intake tract and vent it to the atmosphere or exhaust instead, in my opinion.
Absolutely, there are specific gravity chemical reactions that do not help as well, depending on quality of fuel.
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  #36  
Old 30th December 2015
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Nicksta, you have a good point. My 02 has like 1/4" size holes in the breather bolts, yet my 08 has these as you picture with maybe 1/16".
Why? From my limited understanding the umbrellas only allow pressure out of the breather bolts, not in. I don't know that the stock air cleaner assembly has enough vacuum on the breather bolts to aid the pressure coming out? Also I noticed that small hole in the newer bikes re not small all the way through. Only the final tip is stepped down. Perhaps as a barrier to catch oil and still let enough air out? I went 6k on this set up stock and barely had any oil in the ham can assmy. I ran the 02 SE with the bolts into the cleaner for a spell. It would go 2k miles before seeping. Or 1k with spirited riding. I have since gone to the horse shoe. No worries now.
The 08 I installed the DK foam/screen hex breather bolts instead of the horse shoe. Hard headed probably. The foam clogged and started the rocker covers to leak. These need routine maintenance often, PITA.
I will most likely change this out to a horse unit or with watching this thread maybe something else.
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  #37  
Old 30th December 2015
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Originally Posted by norseXL View Post
The word "stock" should be anugh of an answer,
the Mo-Co knows more about this engines than you would ever imagine.

The only time the small holes are restrictive, is on the very first down-stroke after a start up,

after that the umbrella check-valves prevent any high c-c presures,
as long as everything is in working order.


Tore


.
Like Tore said and the other member said. With a basic stage 1 bike even stage 2 on the street the stock venting is fine. You only need to vent the cam case in extreme high rpm use. Don't tamper with something that works just fine. Also, keep your oil level about a quarter to half when hot on the stick.
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  #38  
Old 30th December 2015
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I know that oil will cause problems as it lowers octane and can induce detonation and such. I do not know what setup was tested but on a stock machine, the blow-by is only a fraction of the induction. I do not see heat being an issue either and the o2 levels so so. now if you are trying to wring out every available ounce of power, sure I guess the cumulative effects have to be considered. you know that egr can actually increase power if applied right. if an epa approved catch system is used it also routes the vapor back to the cleaner. all 50 states it is illegal to vent to atmosphere as the vent system is an emission component. my 440 made more power and ran a whole lot better with the water injection even with the first crappy lead free fuels back in the early 70's.
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Old 2nd February 2016
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Quote:
My personal theory is that HD went to the tiny breather holes to try to build a little crankcase pressure, to help with scavenging. Wet sumping has been a problem with these motors for forever, and it's well known that low crankcase pressures aggravate it. Hell, every motor I've ever set up with gapless rings wet-sumped like a pig.
awsracing, your comment above sparked my curiosity. What do you think might be happening here: I have a 1988 sportster that burns little to no oil and holds good compression. I decided to fit a Krankvent to augment the no longer unavailable cam chest umbrella valve. The upshot is that I now find that the oil sits about 10-15mm higher in the oil tank, so presumably the scavenging and or the oil drainage has improved. The question is why?

Could the ET-Krankvent be reducing the windage so the oil can drain to the sump better? Might that explain the wet-sumping you mentioned at high revs?
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Thanks to everyone for keeping the ball rolling on this especially with introducing the additional point about wetsumping so I went and read up on the breather valve system especially as it was developed over time especially in the Pan to Shovelhead era.
It is possible to have two different problems that while separate are interrelated with one shining light on the other.
We should be able to agree that these engines breathe through the heads and that unless prevented the lower pressure in the air cleaner as opposed to the crankcase will cause vapors and fluid oil if any to flow out the breather bolts and we agree that the engine should be a net supplier of oil mist and spent gas due to heat and blowby. We also see that in the HD both pistons rise and fall at the same time and if you have not done so pull both your heads off, bolt the cyls down with spacers and slowly turn the engine over by hand. A 1200 XL engine is almost but not quite a 1200 single in terms of reciprocating weight. Okay, we agree that while the pistons reciprocate very quickly the volume inside the engine must rise and fall at least 1200 cc though as AWS has noted there is not a lot of actual volume coming out of the breather hose with the engine running. The reason why 1200 CC of air is not huffing in and out of the hose 5,000 times per minute is the load is restriction in the hose primarily as it cannot handle the volume and it is easier to just increase the pumping volume in the sealed engine.
You can prove this if you have an engine with a timing plug at the bottom of the V. Star the bike up, warm up thoroughly, stop the engine and remove the timing plug. Restart the engine and rev to 5,000 rpm while your chosen observer looks in the hole. There's your alternating pressure/volume waves. You can imagine the effect if the timing plug was 3.5 inches in diameter or only one piston diameter as all your oil would be all over the floor very quickly.
Since the only way out is through the heads the oil mist has to move there slowly as the engine runs over time. This is my point about dyno runs as opposed to running for a full tank at 75. Occasionally the rising pressure will push oil out the cylinder bases or blow a rocker box gasket... or maybe not as a lot will depend on the amount of blowby.
AWS is really good on this as he makes you think. Okay a big point is that the rocker boxes are getting a lot of air and are thin aluminum and this hot oil mist is lubing the top end and condensing on the inside of the rocker box top - the coolest part.
We know from dismantling the heads that the breather outlet is below the highest point of the rocker box so if there is a supply of liquid oil low pressure airflow (intake) and gravity will pull it out there again unless something prevents it. We have also noted that the oil drains on the Evo head are not at the lowest point of the rocker box cylinder head assy and that this is above the exhaust port on both cylinders, not a good place for exterior oil drains.
As I worked on limiting these problems I decided to go to solid lifters from Jims which I recommend if you are a valve control freak and use heavier than stock springs. The lifter bores are a growing problem and you are never quite sure what the status of Hydraulics are in non stock applications. They are noisier but that is just the clearance you are supposed to be maintaining. Next I got a set of Hyperformance iron cylinders and converted back to the Shovelhead mounting system using short bolt down studs and Cometic gaskets. These things cannot walk around which is why you get cylinder base gasket weeping. On over bored cases especially this set up controls that tiny little bridge of alu between the cylinder bases. These are not the flaky old stock cyls okay?
This engine was starting to run a whole lot better. The Evo heads were bolted down Shovel style with exterior oil drains and solid bolts closed the head breathers.
Point is that the engine is building up oil in the rocker boxes like an exterior catch bottle on a race bike and now no matter how deep it gets in there it must be forced back into the crankcase one way or the other.
Now we return to wetsumping to complete the picture, thanks for this, as I left my thinking incomplete here. If we imagine an engine that is clear and that has been running hard and we lock it upright like on a lift then shut the motor down where is there oil above the mini sump on the XL engine? It turns out that ALL the oil is above the mini sump. Okay, imagine that due to intense vibration and pressure waves in the sealed pushrod tubes and cylinder drains has restricted oil flow returning to the crankcase and the umbrella valves have not failed yet so it has not escaped to the air filter. As soon as the engine quits and the oil pump stops turning all that oil flows into the mini sump from the rocker boxes and elsewhere. As the engine gradually returns to atmospheric pressure the excess pressure will try to back flow the oil filter aiding gravity. Simply by moving the oil filter to the bottom of the crankcase Buell helped himself here. The Buell oil pump that was integrated into the cam gear cover was an even better idea. The last of the XB race engines had a 4.08 bore/3.125 stroke and a redesigned rocker box area somewhat similar to a Panhead though I do not see details on oil drain back in the images I have seen. Hammer performance might have a set I think.
I will have to check but Delkron might have made BT cases with an inspection door at the bottom for checking the rod bearings so the complete answer for breathing problems might involve tapping a scavenge into the mini sump where wet sumping has to begin.
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