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December 29th, 2005, 08:16 AM   #41
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Re: Crankcase Venting 101

"Is the use of this check valve going to eliminate the oil from running out on the ground in the probable event of being upside down and pinned by the bike?"

Yes.
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December 29th, 2005, 08:36 AM   #42
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Re: Crankcase Venting 101

Originally Posted by Bobzilla
I know you are supposed to remain wheels down but I am working on my freestyle tricks and am in the process of doing a jump where I stay upside down for extended periods of time and the only thing holding me back is the loss of oil.
I hope to witness a demonstration of this "freestyle trick" in the near future.



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December 29th, 2005, 09:07 AM   #43
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Originally Posted by LINEAWEAVER
Gentlemen,

Dry crank singles (those already equipped with a reed valve crankcase) benefit from the additional check valve only with regard to oil containment.

Many OEM singles employ a pulse air system which draws from the inlet box. In opposition to deactivating said system (common practice) I often simply replace the air box tap with that of the crankcase spigot.

The majority of OEM multi cylinder street bike engines are also equipped with such a system. I once again take advantage by routing the crankcase vent to the scavenging inlet.

A vacuum in the crankcase reduces pumping losses and improves ring seal. (a result of increased pressure delta above and below the piston and ring assembly)

I would like to take credit, however, such is old school technology and has been around since the sixties.

I am indeed beginning to realize that unlike crankcase scavenging many of you have not been around since the sixties and therefore much of what I have to say comes across as brilliant. Some content is indeed brilliant, however, I cannot take credit for that which is not my own.

Kind Regards,
Dale

Reprint:
Concept: Apply a vacuum to the crankcase. Rather than putting a breather on the valve cover to let pressure out, actually suck the air out to create a vacuum.

Benefits of Crankcase Evacuation:

1) Cleans up installation (prevents oil leaks from crankcase sources)

2) Reduces parasitic losses from pistons pumping air

3) Improves ring seal

4) Increases HP by 4-7% depending on the application

5) Eliminates PCV and possibility of oil being sucked into intake system

Tech / Method:
Basically seal the crankcase and run a line from the crankcase to an air pump (or other source of vacuum) and from the air pump to a breather tank. Additionally, if necessary, use a vacuum relief valve to ensure vacuum does not get too great. If you put more than 12in vacuum on the crankcase, you can suck the oil off the front and rear main bearings. That would be a bad thing. Alternatively, with the crankcase sealed up tight to achieve good vacuum, you don't want your pump failing either which would allow a severe buildup of pressure in the crankcase then.

Typically, crankcase evacuation systems employ either a "race type" belt-driven pump or use exhaust as a source for vacuum. Both of those can have problems for street application. The belt-driven pumps are almost always specified for full race applications and therefore would need rebuilt every few thousand miles. If you use the exhaust as a source for vacuum and you have mufflers, you may end up with a buildup of oil in your exhaust ahead of the mufflers. Electric pumps can be used but our experience was they are problematic and don't produce enough vacuum.
Hi Dale,

I have three questions: #1 How many psi is 12inches of vacuum? and #2 In another post you stated the valve you made would be too expensive to sell, you reccomended an automotive valve, and one of the posts listed in the this thread listed the ET performance valve for large v twins. With the current rocker box design of the Husaberg's with two vents into one then into the frame, would one of these et vents, or the cheaper automotive vent that you mentioned work if the two vents are "Yed" into one and then into the valve? #3 Is there a concern of having enough vacuum to pull dirt through the weep past the water pump bearing seal into said bearing and the engine?
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December 29th, 2005, 09:27 AM   #44
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Re: Crankcase Venting 101

How many psi is 12inches of vacuum?
12 inches of water is roughly .4 PSI absolute.
12 inches of Mercury is roughly 6 PSI absolute.


In another post you stated the valve you made would be too expensive to sell, you reccomended an automotive valve, and one of the posts listed in the this thread listed the ET performance valve for large v twins. With the current rocker box design of the Husaberg's with two vents into one then into the frame, would one of these et vents, or the cheaper automotive vent that you mentioned work if the two vents are "Yed" into one and then into the valve?

I am not a big advocate of aftermarket "Harley Davidson" crank vents. Most any oil resistant, fast acting valve will suffice.


Is there a concern of having enough vacuum to pull dirt through the weep past the water pump bearing seal into said bearing and the engine?

No.
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December 29th, 2005, 11:43 AM   #45
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Re: Crankcase Venting 101

How many PSI absolute is atmospheric pressure? Or inches Hg. Or inches H2O?
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December 29th, 2005, 12:05 PM   #46
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Re: Crankcase Venting 101

Originally Posted by Smorgasbord
How many PSI absolute is atmospheric pressure? Or inches Hg. Or inches H2O?
Depending on altitude and temperature roughly 14.7 PSI.
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December 29th, 2005, 04:20 PM   #47
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Re: Crankcase Venting 101

Originally Posted by LINEAWEAVER
How many psi is 12inches of vacuum?
12 inches of water is roughly .4 PSI absolute.
12 inches of Mercury is roughly 6 PSI absolute.


In another post you stated the valve you made would be too expensive to sell, you reccomended an automotive valve, and one of the posts listed in the this thread listed the ET performance valve for large v twins. With the current rocker box design of the Husaberg's with two vents into one then into the frame, would one of these et vents, or the cheaper automotive vent that you mentioned work if the two vents are "Yed" into one and then into the valve?

I am not a big advocate of aftermarket "Harley Davidson" crank vents. Most any oil resistant, fast acting valve will suffice.


Is there a concern of having enough vacuum to pull dirt through the weep past the water pump bearing seal into said bearing and the engine?

No.
Thank You Dale.
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December 29th, 2005, 04:40 PM   #48
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Re: Crankcase Venting 101

ET Performance makes the valves not only for the Harleys but to fit in the hose & for automotive applications also. I had one on my 525 KTM & it pulled about 4-5". Simple to install, just cut the breather hose & insert. I have one on my 'Berg but haven't put the gauge on it. Also running them on my drag Ranchero & they seem to last, the automotive ones I had on my Ranchero didn't.
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March 3rd, 2008, 12:27 AM   #49
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RE: Re: Crankcase Venting 101

Anyone know of a supplier or part number for a check valve available in the UK? Taffy....?......
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March 24th, 2008, 01:46 AM   #50
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Just curious here. Would it be that horsepower gains may be had when applying vacuum to the crankcases because a vacuum under the piston helps to pull it down the stroke and as the piston rises vacuum underneath also increases ? In the case of the Berg would it help if a seperate valve or hole was tapped directly into the crankcase (not the gearbox) and then taken to exhaust vacuum along with a breather from the rocker cover. The two could be joined wit a Y piece then go through the one way valve and then to vacuum.

Just thinking out loud here, wouldn't the effect be the same with vacuum just going through the rocker cover as the reed valve would act as a one way valve ?
Cheers Dan
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