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[Bagger]

S&S says it has determined the problem to be the continuous rise and fall of the air pressure in the crankcase, cam chest and rocker boxes.  That the pressure changes are caused by large volume of air moving in and out of the crankcase as the pistons travel up and down.  As a result of this air flow and the changes in pressure in the cam chest, air also flows in and out of the rocker boxes through the cylinder head oil drain passages.  At sustained high speeds the constant in and out flow of air in the rocker boxes interrupts the free flow of oil from the cylinder heads to the cam chest .  In fact a small quantity of oil, pushed up and down by the pressure changes, is trapped in the drain passage, effectively blocking the passage so that no oil can drain out of the rocker boxes .  When enough oil has accumulated in the rocker boxes, it will start to blow out the breather passage to the air cleaner and ends up all over your bike, your passengers new boots, and in extreme cases on your rear tire .

Reason for Oil Blow By:  More air is displaced by the ascending and descending pistons when a 95" and larger kits have been installed, simply because there's bigger pistons moving up and down.  Sustained high rpm riding aggravates blow by because more oil is being pumped into the engine since the pump is turning faster.  The rocker boxes become overwhelmed with too much oil that it cannot separate the oil from the escaping air.  Some stock displacement engines have oil blow-by problems even when ridden moderately, but that is not the norm.  Blow-by does not happen immediately because the oil buildup that causes it takes time to occur.  That's why blow-by sometimes doesn't occur until after sustained high-speed riding.   

From Nov 04 issue of American Iron - Donnie Smith: 

The breather system is all about separating gaseous materials from the oil to allow the engine to vent to the atmosphere without puking oil all over its exterior.  The engine must vent the pressure built up in the crankcase by the ascending and descending pistons.  As the pistons descend in both cylinders, which happens on the power and intake strokes, the air in the flywheel compartment (crankcase), which is below the pistons, is pressurized because there's less space under the pistons for the air to occupy.  The thrashing flywheel assembly also produces a fine oil mist that  combines with the air in the crankcase.  This oily, pressurized air must be allowed to escape, or it will soon blow out the engine's gaskets and seals.  This oily, pressurized air is forced (vented) out of the crankcase, through the spaces between the bearings and races of the pinion bearing, and into the gear case compartment.  It is then allowed to go up the pushrod tubes and into the rocker boxes.  Once in the two rocker boxes, the oily, pressurized air rushes under the rocker arm support plates and into openings that lead to the breather baffle assemblies - there's one in each rocker box.

The first advantage to making the oily pressurized air go up the pushrod tubes is that gravity assists in separating the heavier oil from the lighter pressurized air, but the separation process needs more help than that. 

There is a three-stage system in the rocker boxes for venting the displaced air back into the combustion chamber, where any oil residue is burned off to prevent all but a minimum of emissions from escaping to the atmosphere.

The three-stage system consists of an open-cell foam disc, which can be described as an oil filter gauze element.  This open-cell foam disc, which is shaped like a 1" long barrel, scrubs oil from the oil air vapor.  The disc is very porous and air is easily blown through the foam. 

The oil that gets separated from the air flows through two small return holes in the rocker arm support plate to return to the gear case - unless there's too much oil to deal with!!  The cleansed air is then fed through an umbrella flapper valve (the 2nd stage), which rises to let the air through.  This flapper valves an umbrella-shaped, one-way, rubber valve that lets air out of the engine, but will not allow it to come back in.  Once the piston begins to ascend, pressure in the crankcase drops, and the air in the breather compartment reverses direction.  When this happens, the flaps of the umbrella valve drop down, sealing the vent hole and blocking the cleansed air from returning.  But when overwhelmed will let oil out of the engine along with the air.  The cleansed air then follows a tortuous path in the rocker boxes (3rd stage), which allows air to escape, but separates any residual oil from the air.  (Tortuous is the term used by engineers to describe a channel that gases find easy to follow, but liquids do not.)  After the oil is separated and the gases flow out of the heads, the gasses are sucked back into the carb, or EFI venturi , and into the combustion chamber to be burned.

[Bagger]

Some possible solutions?

a.   Ensure the oil tank is not overfilled.  The tank must have air at the top to allow for venting.  No air equals no venting.  No venting means that excess oil will be forced out somewhere, the first place usually being into the air cleaner.
 
b.   Oil pump alignment.  Pump misalignment can result in premature wear, as well as cause an improper seal against the cam support plate and /or crankcase.  On the cam support (feed) side of the pump, an improper seal allows oil seepage into the gear case and creates a possible blow-by problem.  On the crankcase (return) side, an improper seal might result in less than-ideal oil scavenging of the crankcase/flywheel compartment. 

c.   Ensure drain holes in rocker support plate underneath the breather assemblies are drilled cleanly through - not blocked or rough edges.  Drill holes with #43 drill bit.

d.   Ensure correct oil filter is on the engine.

e.   Check for clogged oil return line.  Be sure the return hose to the oil pan isn't kinked, pinched, restricted.  Pull the hose off and run water through them to be sure.. In colder/humid climates, a hardened "plug" of milky oil condensation-sludge can partially block the hose.  Check passages through the tranny case and pan are open & clear.

f.   Check for excessive cylinder/ring leakage.

g.   Warped or wrongly installed parts will allow excess oil to bleed off into the gear case and the excess oil will be forced up the pushrod tubes where it will overwhelm the breather system.  For example – is the cam support plate warped, if so then oil pump O-ring will not seal the two mating parts.  Is the rocker support plate warped?

h.   Replace the rubber umbrella valves in the breather assembly.

i.   Replace breather assembly foam filter. Breather Filter: HD P/N 63815-99

j.   Replace plastic breather assembly that tend to warp with the metal ones (p/n 17650-02) – Stock on 2004 and up. 

k.   Install two gaskets (p/n 17592-99) under the breather baffle to give the oil a tiny bit more room to accumulate while draining down.

l.   Help the additional air escape the engine more efficiently.  The breather bolts that affix the air cleaner to the heads are hollow.  The holes in the bolts are the way the breather system transfers vented air into the air cleaner assembly – Drill out the breather bolts one or two drill sizes.  Making the holes larger will allow more air to pass through in the same amount of time.

m.   Examine all junctures between oil-passing parts and O-rings – ensure correctly installed.  Some crucial areas are:  1. The side of the oil pump that fits against the cam support plate, which is the pump’s feed side. O-ring #11286 seals the pump against the support plate.  2. O-ring #11301 seals the cam support plate to the engine case.  3. On a TC88B engine there’s an extra feed opening for the counter balancing system, which also takes a #11301 O-ring.  If this O-ring is missing, crimped, nicked, etc., oil will bleed past the junction and down into the gear case.  All 2000 and later cam support plates have this feedhole.

n.   When installing the support plate on a rubber-mounted TC88 motor there’s a screw and washer blocking this feedhole since there’s no counter balancer system in this engine.  If this feedhole isn’t blocked, then oil will be fed right into the gear case, the result being oil blow-by and a loss in oil pressure.

o.   Try an S&S Reed Valve. Not compatible with the Feuling Super Oil Pump. Page 40 - 41 of S&S Catalog
http://www.sscycle.com/catalog16/pg/Twin_Cam/html/Twin_Cam.htm

p.   Try Doherty Mystfree Vents
http://www.dohertymachine.com/

q.   Try TP Engineering Pro Vent Rocker Boxes http://www.tpeng.com/rockerbox.html

[Bagger]

http://www.mklsportster.com/xloilblowbyarticle.htm

Routing the Breather Hose Into the Air Cleaner:  Many Harley mechanics defeat one of the primary benefits of the breather kit when they route the breather hose into the air cleaner, on the inside of the air filter itself.  Besides the fact that this defeats the purpose of the breather in the first place, it allows an oily mist into the combustion mix of your engine.  The engine is designed to ignite a mixture of gas and air in the combustion cycle - adding a heavy oil mist to this mixture serves to greatly contribute to excess carbon formation in the combustion chambers, on piston tops and glaze cylinders as the oil burns along with the gas and air.  Obviously, this leads to an eventual decline in the performance and reliability of the motor in the long term through this and other related factors (such as fouled plugs).
So, if you have your breather hose routed into your air cleaner, reroute it to the atmosphere - the EPA may not approve, but your engine will thank you for it.

Do Crankcase Vents work: 
http://www.nightrider.com/biketech/crankvent_test.htm

Nightrider's Motorcycle Performance Guide can not state that the use of any Crank Vent will enhance the performance of an engine although we have strong subjective evidence that the devices are effective in reducing blown rocker box gaskets. We can state that these devices will not hurt performance.

Nallin Racing Head Service did testing for increased power: 


http://www.nrhsperformance.com/tech_breathervalves.shtml

Bottom line here, folks, I tried my damndest, I can't find power with these devices. I know that pisses some people off. All I have to say is "show me". Don't just show me a result, either, anyone can skew procedures or pick and choose among the full range of results to support what he's trying to say. Show me procedures and ranges of results.
Here are some crank vent products:

http://www.cas4.com/engine/engine-crankcase-breathers-breather-valves2.html
http://www.chopperscycle.com/page/VTS/CTGY/41-311
http://www.kuryakyn.com/products.asp?bn=harley&ci=2350
http://www.speedsperformanceplus.com/products.html
http://www.dohertymachine.com/tech_tips_powervent.html
http://www.dohertymachine.com/catalog_TwinKit.html
http://www.dohertymachine.com/catalog_inlinepv.html

[Bagger]

S&S addresses the issue with their “Reed Valve”.  Their marketing hype is on page 40 and 41 of http://www.sscycle.com/catalog16/pg/Twin_Cam/html/Twin_Cam.htm
S&S says it has determined the problem to be the continuous rise and fall of the air pressure in the crankcase, cam chest and rocker boxes.  That the pressure changes are caused by large volume of air moving in and out of the crankcase as the pistons travel up and down.  As a result of this air flow and the changes in pressure in the cam chest, air also flows in and out of the rocker boxes through the cylinder head oil drain passages.  At sustained high speeds the constant in and out flow of air in the rocker boxes interrupts the free flow of oil from the cylinder heads to the cam chest .   In fact a small quantity of oil, pushed up and down by the pressure changes, is trapped in the drain passage, effectively blocking the passage so that no oil can drain out of the rocker boxes .   When enough oil has accumulated in the rocker boxes, it will start to blow out the breather passage to the air cleaner and ends up all over your bike, your passengers new boots, and in extreme cases on your rear tire .

TP Engineering has addressed the issue with their engines and Twin Cam models as well as all 1992 and later EVO big twins, and 19991-2003 EVO Sportsters.  You can read about TP’s $900 solution at
http://www.tpeng.com/rockerbox.html

Some pictures of the TP Rocker Boxes in this Hot Bike article: http://www.hotbikeweb.com/tech/0303hb_cam/

TP Engineering has a Pro-Vent rocker box that allegedly cures oil blow-by. TP has supposedly reengineered the way oil is separated from the pressurized air sent to the rocker boxes, as well as how the air flows out of the engine and into the breather system.  Easier air movement separates oil from the air more efficiently and eliminates oil blow-by into the air cleaner, without the use of the rubber flappper valves or foam filters to scrub the oil from the air.  TP uses a series of machined labyrinths in its rocker boxes that collect the oil droplets as the oily pressurized air traverses the passages at high speeds.  The separated oil is then returned to the engine, while the now-clean air is allowed to exit the engine and go into the air cleaner.  As the oily pressurized air is created and forced out of the crankcase, it is blown into the gear case, up the pushrod tubes, and into the first chamber of the Pro-Vent rocker box system via three entry holes that begin the process of extracting oil droplets from it.  Each surface touched by the pressurized air collects some of its oil.  The oily pressurized air collides with the walls of the chamber and is forced to make a series of turns before climbing the last wall and flowing through the entry hole into the next chamber.

In the second chamber, the pressurized air also swirls and collides with its walls.  So by the time the air climbs the final wall on its way out of the chamber, it is free of oil and ready to enter the crossover channel in the rocker box cover, which routes the cleaned air out of the head and into the air cleaner.

R&R Cycles
http://www.v-twinforum.com/forums/showthread.php?t=100338&highlight=Support+Plate
http://www.rrcycles.com/store/newrr.html#rrcamplate

The R&R cam plate is vastly differant from all others, it is a camplate/camcover which are both functional and work in conjunction with each other.

Problem 1
When the flywheels shift or have excessive runout the pinion shaft whips causing the camplate to flex and leak oil from its mating surfaces (excessive oil in th case), secondly this excessive runout will cause the oil pump gerotars to bind against the oil pump housing causing some scoring in the oil pump body as Im sure many of you have seen.

Fix 1
The R&R camplate does not mount inside of the camchest instead it is much heavier duty and mounts to the face of the whole camchest making it a much more rigid setup. This reduces the whipping action of the pinion shaft which is turn solves the problem defined above. Secondly the surface between the camplate and camchest in fully gasketed therefore preventing any leaking of oil into the camchest compartment.

Problem 2
Excessive pressure in the case causes oil to stay perched in the heads (oil can't fully gravity return from the heads while case is pressurised i.e. bike is under throttle). This oil gets excessivly hot, and when the bike is dethrottled, this excessively hot oil, when returning to the camchest is easily aireated due to its low viscosity (thiness). Your oil bag oil level will grow from 1/2 to 5/8 inch from cold to hot ladened with this aireated oil . This aireated oil then returns to the engine, since air is compressable the pressure applied to the lifters will compress the air in the oil and then when there is pure hydrology the lifter will start lifting (noisy lifters). The aireated oil does not lubricate engine parts as well either.

Fix 2
The camcover has a oil/air scrapper labyrinth which allows the case to breathe (vent) to atmosphere through a vent on top of the cam cover. This reduces the pressure in the case while under throttle, therefore solving problem 2.

[Bagger]

Oil Down Your Leg? - John Sullivan – Easy Rider Magazine
Easyriders January 2006
Issue 391|
Pgs. 160-161

Product Review

http://www.dohertymachine.com/easyriders2006.php?osCsid=b7aa2cc4d3273efb88157600127953e5
http://www.dohertymachine.com/product_info.php?cPath=1&products_id=99

Harley's Twin Cam 88 is a great motor. In stock from they make half again as much power as the Evo did and there are off-the-shelf kits to build them up to 124 inches. They have only one area of concern, which involves the cylinder head breather system. It seems that some motors pump oil out of the cylinder head breather passages into the air filter or whatever they are connected to. If your motor's breathers are routed to the air filter back plate, you could wind-up with a bit of oil running down your right leg after a long ride.
This is not a new problem. We first saw it back in 1999 and there appears to be more than one reason for it. These include combustion gases leaking past the piston rings, incorrect alignment of the oil pump, poor sealing of the oil system's O-rings, not enough volume of the scavenge side of the oil pump and inadequate oil separation in the breather valve. Not all of these items occur in every motor; in fact we would be surprised to find one motor with all of them.

We think that the two biggest reasons for excessive oil blow-by are incorrect alignment of the oil pump and poor oil separation in the cylinder heads' breather valves. Most of the oil pump alignment problems are caused by inexperienced technicians who are installing camshafts and do not follow the correct oil pump alignment procedure when the reinstall the cam plate. The poor oil separation up in the cylinder heads is caused by the stock breather valves being overwhelmed by the volume of oily/air mist that gets up to the valves during a really hard ride.

Tim Doherty of Doherty Machine has spend the past several years working on the oil separation problem in the cylinder heads and he's come up with a new breather valve design. After looking at his design, he is either very smart or an ex-farmer. His Mystfree valve uses a two-chamber oil separator, whereas the factory breather valves have a single chamber separator that is fitted with a gauze element.
In the Mystfree design the first, or stock oil separation chamber, which is cast into the center of the rocker arm support, is augmented by a cylinder that protrudes into it from the bottom of the Mystree valve body. This cylinder has three openings spaced around its edge that cause the pressurized air- oil mist that is inside of the motor to change direction several times as it is pushed towards the exit in the breather valve.

As this mist moves up against the walls of the cylinder, a good deal of its oil content is stripped off and returned via the stock bleed holes in the bottom of the chamber. It's kind-of like when the wind pushes damp air through plants and their leaves catch the dew.

When the pressurized air passes through the six holes in the Mystfree valve, it hits the bottom of the neoprene valve cause it to rise up forming a second chamber. At this point any oil remaining in the air is removed by the aluminum valve seat and drains back through the lower chamber and into the rocker box.

The neoprene valve that Tim uses is of a smaller diameter than that of the stock umbrella valve, it therefore develops a higher vacuum in the second separation chamber, which helps to pull any oil back into the cylinder head's rocker box. The idea behind the Mystfree valve is sound and his machining is flawless.

Having seen how well the Mystfree valve worked in a 95-inch motor, we decided to use them in a high performance 103-incher we are building. The Doherty Mystfree breather valves are installed in the same manner as the stock breather valves and come with all needed gaskets and mounting bolts.
- John Sullivan
Easyriders

 
IMPORTANT SUPPLEMENTAL INSTRUCTIONS
NOTICE FOR ALL
FL MODEL MOTORCYCLES
 
FL Model Motorcycles require a total oil capacity of 4 quarts. Overfill conditions can result in oil carryover even after the installation of the Mystfree units. When oil and filter is changed in an FL Model the recommended refill capacity is 3.5 quarts NOT 4 quarts since approximately ½ quart remains in the engines sump and gear case during an oil change.
 
DRILLING ROCKER ARM STANDS (OPTIONAL ALL MODELS)
Included in your Mystfree kit is a number 43 drill bit, which measures .089 in diameter. There are two oil drain return holes located in the rocker arm stand cavity in which the Mystfree mounts. 

We have found that the oil return holes in the rocker arm stand are too small to adequately return standing oil. If you are experiencing a high volume of oil carryover exiting the breather system; we recommend the following modifications: These two holes presently measure .060 in diameter. In Twincam 88 style engines, that are moving above normal amounts of oil to the rocker box area, it is recommended that these holes be enlarged to .089. This is easily accomplished by removing the rocker arm assemblies and enlarging the holes with a common electric or portable drill with the drill bit that has been provided in your kit. If you need further technical assistance, please contact Doherty Machine at 928-541-7744.

[Hoist!]

My solution. Doherty Power Pacc and run the breather tubes to the ground, instead of the backplate of the air cleaner. Just like the good old days when the crancases themselves were vented to the ground. This complicated breather system is another result of EPA laws and not better engine designs. You'll never see a drag racing engine that's not directly venting the crancase. And they're venting to the atmosphere! HD did the same for years. My '85 has a crankcase vent tube run from the case to the bottom of the frame. I bought S&S cases for my Pro Street that are "old style" cases with the same type of crancase venting. I'm now running the DPP vents from the heads to the ground. I don't need that chit filthying up my air cleaner so I can burn that oil instead of venting it. And most of it just drips out of the backplate anyway and spews everywhere as you're riding. We can't change this engine design without replacing these engines. But we don't have to vent the breathers into the air cleaner either. Hoist!

[SOKOOLJ]

BAGGER,

Looks like somebody did my home work again. LOL. Thanks for the info.

SOKOOL

[djkak]

My solution. Doherty Power Pacc and run the breather tubes to the ground, instead of the backplate of the air cleaner. Just like the good old days when the crancases themselves were vented to the ground.....HD did the same for years. My '85 has a crankcase vent tube run from the case to the bottom of the frame. I bought S&S cases for my Pro Street that are "old style" cases with the same type of crancase venting.......Hoist!

Not that it matters one way or the other but H-D crankcases have been vented to the air cleaner since Jan 1, 1978; the beginning of the "Ham Can" era. To be more specific, 1978 Big Twins with a sequential VIN >= 60,000 are emission units equipped with the Prestolite electronic ignition and vented Ham Can air cleaner. Previous to this the crankcase vent, supplemented with oil from the return pump was used to lubricate the rear drive chain.

djkak

[Hoist!]

Not that it matters one way or the other but H-D crankcases have been vented to the air cleaner since Jan 1, 1978; the beginning of the "Ham Can" era. To be more specific, 1978 Big Twins with a sequential VIN >= 60,000 are emission units equipped with the Prestolite electronic ignition and vented Ham Can air cleaner. Previous to this the crankcase vent, supplemented with oil from the return pump was used to lubricate the rear drive chain.

djkak

Yeah dj, and we've been diconnecting them from the A/C since then too. My '85 breathes thru the case. There are no breathers from the heads. They vented the crankcase into the air cleaner, which we simply relocated to the atmosphere. I'd rather drip on the floor than destroy my air cleaner and spew all over the bike. Hoist!

[Bagger]

My engine spits oil.  I've tried Doherty Powerpacc, Doherty Myst Free Vents, TP Engineering Pro Vent Rocker Covers, aligned the oil pump several times, ensured all pump mating surfaces and O rings were good and have used a Delkron rocker arm support plate with cleanly drilled drain holes - the engine still continues to spit oil.  Solution now is I accept it due to increased crankcase pressures and I route the breather bolts to the atmosphere.  

2002 FLHRI - 98 ci
(9.48:1 CR) (9.02:1 Corrected CR) (198 psi F/R Cyl.)
Revolution Performance 98" Cylinders
CP Flat Top Pistons
Baisley Super Stock Heads (84cc)
0.040" Head Gasket
TP Engineering Pro-Vent Rocker Boxes
SE Roller Rockers
JM20 gear drive cam
Horsepower Inc 48mm TB
Doherty PowerPacc w/Ness Big Sucker Stage II Filter
Doherty PowerVents
RB Racing LSR 2-1
3.37 final gear ratio
Dyno Jet PCIII USB

[Hoist!]

You know, I just realized your name was Bagger. Welcome to the site man! We have a member, formally known as Bagger, who now goes by REGGAB. I never realized it wasn't him. No wonder you asked who Chuck was. Then I called you Henry. Sorry! Nice engine package you got. Must go nice. Enjoy the site! Hoist!

[bisounours]

Good morning (New) Bagger,

I send you the  from FRANCE.

Thanks for the informations.

It'll be nice for the other members if you present you in the thread "New Member Introduction"
with a pic of your bike 

Best regards

  Jacques

[EAGLE1]

Do Crankcase Vents work: 
http://www.nightrider.com/biketech/crankvent_test.htm

Nightrider's Motorcycle Performance Guide can not state that the use of any Crank Vent will enhance the performance of an engine although we have strong subjective evidence that the devices are effective in reducing blown rocker box gaskets. We can state that these devices will not hurt performance.

I just read the info here and found it very informative, but have found myself in sensory overload with all the differnet products and options, I recently had to have the rear blown rocker box gasket replaced and have surmised it was due to a hard ride back from chi-town at 90+ for a good hour. I have never had oil spitting out of the breather, except when the oil was over filled, but i don't want to worry about the rocker box gaskets every time I run her hard on the 4-laner. these ET krank vent only vent the crank case and block off the head breathers,  while the Doherty Machine Mystfree breather valves vent the heads to the A/C or  to atmosphere     I'm really not sure what would be the best solution for my problem, any suggestions would be appreciated.

[HWYMAN1]

My solution. Doherty Power Pacc and run the breather tubes to the ground, instead of the backplate of the air cleaner. Just like the good old days when the crancases themselves were vented to the ground. This complicated breather system is another result of EPA laws and not better engine designs. You'll never see a drag racing engine that's not directly venting the crancase. And they're venting to the atmosphere! HD did the same for years. My '85 has a crankcase vent tube run from the case to the bottom of the frame. I bought S&S cases for my Pro Street that are "old style" cases with the same type of crancase venting. I'm now running the DPP vents from the heads to the ground. I don't need that chit filthying up my air cleaner so I can burn that oil instead of venting it. And most of it just drips out of the backplate anyway and spews everywhere as you're riding. We can't change this engine design without replacing these engines. But we don't have to vent the breathers into the air cleaner either. Hoist!

Howie,
Okay I will be the stupid one and ask, what kind of tubing from the breather bolts, how long, and exactly where do you vent to ? Any pix? thanks john

[GMR-PERFORMANCE]

Very good tips in this post. WE do all of the mods to the engines when they are for misting. One thing I do not like is the S&S reed valves. I have several here that i would be happy to send to some one if they want to try them. But what we have found is they will sump the engine due to the reed being too stiff. We have pulled them from the 124 crate engines and have sen 5-6 hp as a increase and puking is gone. But then a 124 S&S is a different animal then a normal t/c with there pump and cam plate, cam cover.

[Hoist!]

Howie,
Okay I will be the stupid one and ask, what kind of tubing from the breather bolts, how long, and exactly where do you vent to ? Any pix? thanks john

Hey John, I haven't modified it yet, but the Doherty PP already has tubing connected to the Power Vents, that bolt to the head breather, and the tubing connects to the DPP Backplate. These tubes can be run directly to the ground instead of the backplate. I believe that the tubing is 1/4" or 5/8". I plan on connecting both tubes from the Power Vents to a tee, and runnng a single line down to the ground. I'd route that line behind the throttle body, between the barrels, behind the horn, and down to the ground on the opposite side, between the engine case and inner primary. Not much of the tubing would be visible that way. I hope this is clear, but when I do it, I'll get some pics of it. Hoist!

[djkak]

......I do not like is the S&S reed valves. I have several here that i would be happy to send to some one if they want to try them. But what we have found is they will sump the engine due to the reed being too stiff. We have pulled them from the 124 crate engines and have sen 5-6 hp as a increase and puking is gone.....

In late ’05 I installed a set of gear drive cams in my ’02, 103” Road Glide. When planning the job, I looked at installing the S&S crankcase vent. I didn’t have a problem with air cleaner oil carryover, even with the old style back plate; sure the air cleaner would get oily over time, but I never had oil accumulating between the pushrod tubes below the air cleaner.

I installed the S&S crankcase vent along with the gear drive cams and afterwards my machine immediately started dripping oil from the air cleaner which accumulated between the pushrods below the air cleaner.

I removed the cam plate assembly, inspected the cam chest area and discovered something interesting; first a little background. In the Pre-Twin Cam engines a full-circle airflow had to be established in order to effectively return oil collecting in the pushrod tubes and rocker boxes, where it accumulates after lubricating the valve train. This full-circle airflow although necessary, did not exist prior to the mid 1982 production machines. It is worth mentioning at this point that this airflow concept is not necessary or even possible in the standard Twin Cam engine. 

A “breather gear” valve is used on pre Twin Cam machines to control the flow of air and oil from the crankcase (flywheel area) to the gear-case cavity (cam-chest). An oil pickup in the gear-case cavity returns oil back to the oil tank. The breather gear opens on the piston down-stroke transferring oil and air to the gear-case cavity and closes on the piston upstroke, creating a negative pressure in the crankcase which is intended to draw the returning top end oil into the crankcase.

It’s funny to think about it now, but prior to mid-1981 the rocker box/pushrod tube area was not vented to anything. The pistons go up; the breather gear closes, creating a negative pressure in the crankcase and top end return, but little oil flows. The un-vented rocker boxes cause the oil flow to stop just like the Coca-Cola you are trying to suck out of an upturned bottle; the pressure drawing the oil down the return passage is matched by the negative pressure in the rocker boxes.

By the middle of 1981 production, HD realized there was a big issue with oil accumulating in the push rod tubes and rocker boxes. Their fix was to connect the bottom of the pushrod tubes to the base of the cylinders with fittings and hose. The idea was to apply a negative pressure to the bottom of the pushrod tubes on the upstroke of the pistons in order to evacuate the oil. The problem with that approach is that on the upstroke of the pistons, the same negative pressure is applied at both ends, the oil return hole in the bottom of the cylinder as well at the bottom of the push rod tubes.

By the middle of the 1982 production, the answer became clear; connect the pushrod tubes to the gear-case (cam-chest) with a passage through the tappet blocks. This allows the positive gear-case pressure up the pushrod tubes, over the rocker boxes and down the top end oil return hole in each cylinder and finally into the negatively pressurized crankcase area; full-circle.

The result of this change was dramatic and the oil flowed freely. This concept can be best illustrated by comparing the EVO tappet blocks to the Shovel units. The modified Shovel tappet blocks each have two small holes, approximately 1/8” to accommodate the air flow up the pushrod tubes. The EVO tappet blocks both have large air chambers built into them to accommodate the moving air/oil.

Enter Twin Cam oiling system and the S&S reed style crankcase vent. The S&S vent performs a similar function to the old H-D breather gear. On the piston down-stroke air and some oil mist are transferred from the crankcase area to the cam-chest. On the piston upstroke the reeds close, creating a negative pressure in the crankcase. I can relate to this; kind of warms the heart. Well there is one small detail, the Twin Cam top end oil drain passages no longer run into the crankcase area. Twin Cam top end oil is routed down the cylinder and into the cam-chest area. The air movement that was essential for good oil control in the EVO and earlier machines is no longer necessary in the Twin Cam engine.

The S&S vent increases the cam-chest pressure as well as the pressure differential between the cam-chest and air cleaner. This is significant because Twin Cam top end oil no longer drains into the crankcase flywheel area. The pressure differential that worked so well in the pre Twin Cam engines now works to promote air movement from the cam-chest area up through both the pushrod tubes and top end return passages, out to the air cleaner. Enough air/oil movement in this direction can exceed capacity of the air/oil separators resulting in oil carryover.

I removed the S&S crankcase vent, put my machine, now 113” back together and the old girl runs clean and dry.

djkak

It is my sense that the wet-sump condition in a Twin Cam equipped with an S&S vent, results from reduced return pump efficiency. The lowered efficiency is caused by the substantial increase in the pressure differential (negative crankcase pressure) between the oil return pickup in the crankcase and the cam-chest / oil reservoir. I believe that a certain amount of positive crankcase pressure would improve the return pump’s efficiency rather than reduce it; JMHO.

djkak

[Bagger]

GMR

I've read about others experiencing sumping issues too with the S&S Reed Valves and they are not compatible with the Feuling oil pump. 

Particularly with the newer bikes, most guys won't know just how much oil is being sucked into the throttle body due to MOCO's direct routing from the crankcase breathers off the head to the throttle body.  As was mentioned in a previous post, routing the breather hose into the throttle body allows an oily mist into the combustion mix of your engine.  The engine is designed to ignite a mixture of gas and air in the combustion cycle, adding a heavy oil mist to this mixture serves to greatly contribute to excess carbon formation in the combustion chambers, on piston tops and glaze cylinders as the oil burns along with the gas and air.  Obviously, this leads to an eventual decline in the performance and reliability of the motor in the long term through this and other related factors (such as fouled plugs).

Here's another tip I just picked up from Latus Harley Davidson forum.

Oil out of one cylinder would indicate it's the breather assembly in the rocker housing. Could be the O ring under the rocker support is missing, the umbrella valve is warped or unseated, blockage of the drain back holes in the rocker support, bad breather assembly gaskets or warped breather assembly.

It can also be a drain back problem from the head down through the cylinder to the cam chest. This can be checked by pulling the top rocker cover and cam cover. Then blowing compressed air either up the return channel in the cam chest or doing the same from the hole next to the exhaust valve spring (blowing down into the cam chest) to see if it is clear.

[HWYMAN1]

Hey John, I haven't modified it yet, but the Doherty PP already has tubing connected to the Power Vents, that bolt to the head breather, and the tubing connects to the DPP Backplate. These tubes can be run directly to the ground instead of the backplate. I believe that the tubing is 1/4" or 5/8". I plan on connecting both tubes from the Power Vents to a tee, and runnng a single line down to the ground. I'd route that line behind the throttle body, between the barrels, behind the horn, and down to the ground on the opposite side, between the engine case and inner primary. Not much of the tubing would be visible that way. I hope this is clear, but when I do it, I'll get some pics of it. Hoist!

Howie,
Got most of it. will print out direction and walk out to bike. I'll wait until you "engineer" the size and length of tubing before I try it though. I just was not sure which way you were going to take  it to "gravity". John

[HWYMAN1]

GMR

I've read about others experiencing sumping issues too with the S&S Reed Valves and they are not compatible with the Feuling oil pump. 

Particularly with the newer bikes, most guys won't know just how much oil is being sucked into the throttle body due to MOCO's direct routing from the crankcase breathers off the head to the throttle body.  As was mentioned in a previous post, routing the breather hose into the throttle body allows an oily mist into the combustion mix of your engine.  The engine is designed to ignite a mixture of gas and air in the combustion cycle, adding a heavy oil mist to this mixture serves to greatly contribute to excess carbon formation in the combustion chambers, on piston tops and glaze cylinders as the oil burns along with the gas and air.  Obviously, this leads to an eventual decline in the performance and reliability of the motor in the long term through this and other related factors (such as fouled plugs).

Here's another tip I just picked up from Latus Harley Davidson forum.

Oil out of one cylinder would indicate it's the breather assembly in the rocker housing. Could be the O ring under the rocker support is missing, the umbrella valve is warped or unseated, blockage of the drain back holes in the rocker support, bad breather assembly gaskets or warped breather assembly.

It can also be a drain back problem from the head down through the cylinder to the cam chest. This can be checked by pulling the top rocker cover and cam cover. Then blowing compressed air either up the return channel in the cam chest or doing the same from the hole next to the exhaust valve spring (blowing down into the cam chest) to see if it is clear.

Did not mean to internally jack your thread. but this is great info on a common problem and I may have found the cheapest answer to a problem  yet! john

[Midnight Rider]

John, agree that it might be a good solution to the problem.  With the Doherty PP, we see what is really coming out of the engine, as it is piped into the bottom portion of the backplate, and not directly into the vortex of the TB throat.  So pure liquid won't get in there (the TB) because the heavier oil tends to collect in the clear tubes until enough is there to be pushed beyond the backplate, which ultimately shows up by dripping out the bottom of the A/C.  Mine is very slight since I've allowed the oil level in the crankcase to reach it's happy point (about 1/2 quart from full), but it still pukes a bit at high running speeds.

If Howie can come up with some plumbing that doesn't look like a Monkey's A$$ sewn up with a Grapevine, I might be interested in following his lead...

[Hoist!]

If you check the left side of the bike, there's a small gap between the inner primary and the case. The only exposed line will be at the bottom of the barrels after it comes down past the bottom of the horn. I unfortunately found no good location on the right side on the '07. Maybe a SS Braided line would look better. If anyone comes up with a better "hiding spot" for this line, let me know. That was the least conspicuous way I found to route the line. You need a line size tee, or maybe increase the "bull" of the tee one size to tie the 2 breather lines from the PV's into 1 outlet. I thought that was better than running both lines directly down. Then we either find plugs for the backplate holes or put a screws into a short piece of hose left in the 2 backplate openings, and fasten with hose clamps. This is Hoist Redneck Engineering hard at work here guys! Hoist!

[dejavo]

Connect the tee behind the A C cover then run down the right front. go along lifter covers and then forward. use clear tubing. It will be almost invisable. Note- use hose clamps on all nipples if not a few heat cycles later they will leak around the tubeing.

[Hoist!]

Connect the tee behind the A C cover then run down the right front. go along lifter covers and then forward. use clear tubing. It will be almost invisable. Note- use hose clamps on all nipples if not a few heat cycles later they will leak around the tubeing.

Thanks mr. I looked at that and felt less tubing will be exposed by taking it to the left side, since you can drop between the inner primary and the case. Have you done this already? If so, do you have any pics of it? Thanks for your input. Hoist!

[HWYMAN1]

Thanks mr. I looked at that and felt less tubing will be exposed by taking it to the left side, since you can drop between the inner primary and the case. Have you done this already? If so, do you have any pics of it? Thanks for your input. Hoist!

Howie,
I would like to see this too. After your posts yesterday, i talked to doherty (josh) and of course if you check this out: http://www.dohertymachine.com/product_info.php?cPath=2_23&products_id=156&osCsid=eb672872ad26b34a26d80d49fa0cb985
they feel that you don't need to have long run off as the filter will collect any residual OIL/MIST. john

[Hoist!]

Howie,
I would like to see this too. After your posts yesterday, i talked to doherty (josh) and of course if you check this out: http://www.dohertymachine.com/product_info.php?cPath=2_23&products_id=156&osCsid=eb672872ad26b34a26d80d49fa0cb985
they feel that you don't need to have long run off as the filter will collect any residual OIL/MIST. john

John, I'm reluctant to try that, as I've used them on Evo applications and wasn't thrilled with the results. It's fine for awhile, but then the filter eventually gets saturated and it starts dripping from that filter. Air Filter or Auxillary Filter, they get wet and drip, then spray the bike at speed. That's what I'm looking to eliminate. But that filter would at least keep your Air Filter cleaner than it is now. That thing is a black mess!

Hoist!

[HWYMAN1]

John, I'm reluctant to try that, as I've used them on Evo applications and wasn't thrilled with the results. It's fine for awhile, but then the filter eventually gets saturated and it starts dripping from that filter. Air Filter or Auxillary Filter, they get wet and drip, then spray the bike at speed. That's what I'm looking to eliminate. But that filter would at least keep your Air Filter cleaner than it is now. That thing is a black mess!

Hoist!

i asked about the saturation rate and got a vague answer "it depends....", but this is their attempt at keeping any oil from air filter element. john

[Hoist!]

i asked about the saturation rate and got a vague answer "it depends....", but this is their attempt at keeping any oil from air filter element. john

Key word being "attempt". Attempts don't always work though, do they? My idea will work for sure. That's the way it's been done for years, before emmissions requirements. Hoist!

[HWYMAN1]

Key word being "attempt". Attempts don't always work though, do they? My idea will work for sure. That's the way it's been done for years, before emmissions requirements. Hoist!

your right Howie!  so now you need to retro engineer this thing and get us PIX!!! john

[Hoist!]

your right Howie!  so now you need to retro engineer this thing and get us PIX!!! john

I'm bringing the bike in Tues for some work. I'm doing it after I get it back. I'll come up with something John. Hoist!

[Hoist!]

Here's a pic with some 1/4" clear tubing showing how I plan on routing it. It runs thru the barrels and along the cylinder base, and down between the inner primary and the case. You could barely see it. I wonder what it will look like when it gets coated with dark oil. Those original clear tubes that go from the breathers to the backplate are pretty ugly right now. Maybe use black hose? What about braided SS? Hoist!

[dejavo]

Hoist
Sorry I didn't reply sooner. I have the installation on two bikes 04 se elect & 07 road glide W 113 engine. The 04 is w doherty crank vents then the tubing as described earlier . The 07 1s just off nipples that were drilled and tapped into the extensions of the backing plate. Both are almost invisable. Yes the clear tubing does discoler after a little normal use but they are still virtually unnoticeable . The installation as I described earlier is a no-brainer (works for me) and if you decide on another direction later you have invested about $2.00 and five minutes for install.Sorry I don't have a dig camera and am also comp illiterate so I can't send pics .

[REGGAB]

You know, I just realized your name was Bagger. Welcome to the site man! We have a member, formally known as Bagger, who now goes by REGGAB. I never realized it wasn't him. No wonder you asked who Chuck was. Then I called you Henry. Sorry! Nice engine package you got. Must go nice. Enjoy the site! Hoist!

Howie, DUDE.  That was me who asked you who da f^ck Chuck was.  I think you were thinking I was Chief or sumpthin'.  You been checked for Alzheimer's Disease lately Brother?    And you called the new Bagger, Henry?  Man you just insulted him.  I'm a troublemaker.  Not sure he wants that moniker. 

And Bagger!  Dude, welcome to CVO Harley.  Very KEWL handle you have there.  Do us all a favor and post in the new members section and post a picture of your scooter so we know who you are and what you ride.  Knees in the breeze Brothers.

[HWYMAN1]

Here's a pic with some 1/4" clear tubing showing how I plan on routing it. It runs thru the barrels and along the cylinder base, and down between the inner primary and the case. You could barely see it. I wonder what it will look like when it gets coated with dark oil. Those original clear tubes that go from the breathers to the backplate are pretty ugly right now. Maybe use black hose? What about braided SS? Hoist!

Howie anymore retro engineering for your "blow by" project? john

[Hoist!]

Howie anymore retro engineering for your "blow by" project? john

Hang in there John. I need the bike in order to do this. There's a chance, albeit a small one, that I'll be switching to the S&S Single Port Dual Induction System at my tune, after I get the bike back. But if I keep the DPP, I'll definitely be rerouting the breather lines beneath the bike as I showed earlier. Hoist!

[SneakyPete]

I am running a Zipper's AC assy with external crankcase breathers.  I was using a stainless filter assy mounted behind the AC but have grown tired of cleaning it every other time I ride so oil does not accummulate, drip and blow all over my exhaust and saddle bag.  I didn't like any of the options available but think I have something that looks good and does the job.  I bought some Sterling Chromite II braided hose with their chrome connectors and made my own.  I think it looks pretty good and works great.  Here are some pics of the install.
 

[SneakyPete]

Rear view looking forward...

[SneakyPete]

Left side view, cable clamp secures hose to transmission cover....

[SneakyPete]

Right side, forward view looking back...

[SneakyPete]

End of hose on left side under frame run between inner primary and engine case...

[Chief]

Seems to me they should be able to find a way to vent the heads and oil pan in a common vent that would let the oil collect in the pipe and harmlessly drip back into the oil tank.

[rednectum]

Seems to me they should be able to find a way to vent the heads and oil pan in a common vent that would let the oil collect in the pipe and harmlessly drip back into the oil tank.

see raggabs bike .

[SneakyPete]

see raggabs bike .

Where would I see it and what did he do?

[rednectum]

Where would I see it and what did he do?

sorry, i forgot, you cant see it because im riding it. he posted some pictures on this forum.

[spydglide]

sorry, i forgot, you cant see it because im riding it. he posted some pictures on this forum.

........."and what did he do?"........concerning the oil blow by problem     spyder

[Twolanerider]

........."and what did he do?"........concerning the oil blow by problem     spyder

Spyder, I remember the video of Henry's engine running.  Nothing to be seen there as no breather assemblies of any kind were yet installed.  So unless it was textually described elsewhere the "it" hasn't actually been explained yet.  Still a riddle, wrapped in a mystery, inside an enigma, hidden by a rocker box.

[spydglide]

Spyder, I remember the video of Henry's engine running.  Nothing to be seen there as no breather assemblies of any kind were yet installed.  So unless it was textually described elsewhere the "it" hasn't actually been explained yet.  Still a riddle, wrapped in a mystery, inside an enigma, hidden by a rocker box.

well, if there is a 'solution' that we could find or has already be identified, then I sure would like to know of it.  I think part of my oil blowing out the breather problem is my insistance on adding oil to keep it 'full'.......maybe?  Might try changing the puke tube to a collection filter......but as Hoist said.....that's just relocating the 'oil-mess'.  har!  spyder

[Twolanerider]

well, if there is a 'solution' that we could find or has already be identified, then I sure would like to know of it.  I think part of my oil blowing out the breather problem is my insistance on adding oil to keep it 'full'.......maybe?  Might try changing the puke tube to a collection filter......but as Hoist said.....that's just relocating the 'oil-mess'.  har!  spyder

"Full" is certainly a relative term on these things Spyder.  Before the top end was redone on mine last winter in its original trim it would push out oil until it got to 1/2 quart low when hot.  Then it would stay there and use another 1/2 quart in about 4000 miles.  Between that point and 5000 whenever it was convenient I'd change it, refill with Amsoil to or Mobil 1 to a 1/2 quart low and then repeat the process.

Since the top end was redone, however, the new Zippers build (and I use the term lightly) pukes out oil; period.  Their head design is very very good for external engine oil lubrication patterns and methods.  I'm sure there's a patent in there somewhere for "engine supported external rust elimination system."  Personally I'm just proud to have been allowed to be part of the research.

[spydglide]

  Personally I'm just proud to have been allowed to be part of the research.

I guess 'proud' could be one way to describe your feelings.   har!  spyder

[REGGAB]

Spyder, I remember the video of Henry's engine running.  Nothing to be seen there as no breather assemblies of any kind were yet installed.  So unless it was textually described elsewhere the "it" hasn't actually been explained yet.  Still a riddle, wrapped in a mystery, inside an enigma, hidden by a rocker box.

If I've done this right, you can see the video here:  http://s95.photobucket.com/albums/l149/claydbal/henry%20build/?action=view&current=fix.flv  There is a 90 degree elbow at the top rear of the cam support plate that vents the crankcase.  The hose runs from the elbow between the frame and the oil bag venting to atmosphere.

[SneakyPete]

In my never ending search to find new and better solutions to known problems, I decided to try Kuryakyn's "bluegrass" crankcase vent system (part #9932).  While the arrangement I posted previously works well and doesn't look too bad, I wanted to try to eliminate the hoses altogether while still not having something that needs to be maintained (cleaning breather filters, emptying canisters, etc.).  I can now say the Kuryakyn product meets my expectations.  The key with this product is the banjo fittings point upward so you can run 5/16 fuel hose from each to a tee connection into a single 5/16 line running down the backbone under the gas tank which then runs parallel to the gas tank overflow hose and exits just forward of the rear swingarm.  Totally invisible and maintainance free.  In fact this arrangement acts more like a mini-expansion tank for the oil as most of the mist created drains back into the engine where it belongs.  Should be compatible with most AC assemblies, the banjo fittings are universal thickness.  I used these fittings with the Zipper's breather bolts used with their AC assembly, works fine

[SneakyPete]

Another shot of the right side...Also note that there is just enough room under the tank for the 5/16 line and it must run down the right side.

[sanjoseduke]

Very good tips in this post. WE do all of the mods to the engines when they are for misting. One thing I do not like is the S&S reed valves. I have several here that i would be happy to send to some one if they want to try them. But what we have found is they will sump the engine due to the reed being too stiff. We have pulled them from the 124 crate engines and have sen 5-6 hp as a increase and puking is gone. But then a 124 S&S is a different animal then a normal t/c with there pump and cam plate, cam cover.

Wow these are some great articles on misting. One question is why do only a small number of bikes have this problem?
I had a major venting problem on my 2006 CUSE ( Freedom gear drive cams) in 2006 on a fast, hot (110 plus degree temp)  several day ride through death valley and the Arizona desert. The HD shop in Colorado springs fixed it by installing the S&S reed valve. I have put on over 20k miles since with zero venting problems. Should I be worried about sumping (whatever that is) now ?

[rednectum]

sorry for just now getting back to this thread. my idea on henrys bike was to allow gravity to seperate oil from air. by running the vent hose upward , the oil will not pump out but venting will still occur, the oil is allowed to drain back into cam chest where scavenge pump can pick it up and return to tank.

since that time, and after lengthy talks with r and r, it was decided that the cam plate vent should be plugged on baggers! ahhhh the fun of testing new products!

[Twolanerider]

I've had this problem on the red bike.  Tried a few things that all changed it a little; some better, some worse. 

Those Kuryakyn vents were helpful just because of the direction they vented.  The Doherty MystFree product helped, but not a lot.  Made sure o-rings under the rockers were good, everything else that's at least moderatly easy to service and check.  Finally just routed up down and around to let gravity do its best and let the rest mark a spot as need be.  It's not all over the bike.  It's not making any real mess.  So I can live with it.

Over the winter the top will be back off though.  Might consider another alternative then while it's all in hand.  Does anyone have any experience with the TP "Pro Vent" rocker boxes.  There's an ex Big Dog dealer that is selling some at a surprisingly reasonable price.  Would be willing to give them a shot if they're as helpful for this problem as their advertising makes them out to be.

[rednectum]

twolane, another little trick is to drill the small drains that are below the breathers. look under the breather body and you can see 2 teeny holes through the rocker support, drill about 2 number sizes larger, maybe a little more, theory is this will allow the oil to drain away from the gauze a little quicker, allowing more air/less oil to go through the umbrllas.

[Twolanerider]

twolane, another little trick is to drill the small drains that are below the breathers. look under the breather body and you can see 2 teeny holes through the rocker support, drill about 2 number sizes larger, maybe a little more, theory is this will allow the oil to drain away from the gauze a little quicker, allowing more air/less oil to go through the umbrllas.

Already did that one also.  Don't remember for sure the number size bit used but remember thinking it was gaining .008-.010 over what the hole was to begin with.