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[Dan_Lockwood]

I have a quick question about crankcase venting.

On my new Ultima EVO style motor on my boardtrack project, I have an air cleaner with internal vent tubes one from each rocker box and leading into the carb/air cleaner throat.

I also have a crankcase vent fitting just above my oil pump.

If I run the rockerbox vents into the carb throat, do I still need to vent the crankcase?

I would prefer to NOT run the case vent if I don't have to, but I don't want to over pressure any of the seals.

So what are my options?

Boy, doing this from my iPhone, it takes a while typing.

[DCFIREMANN]

On the newer EVO motors the vent were in the heads. If you have the vent in the heads you should not need the crankcase vent. The early EVO motors had the crankcase vent.

Be Safe

THE DAWG

[Gone Fishin']

Evo and iPhone. Now that's what I'd call a hybrid.

Ride safely,
Louis

[Dan_Lockwood]

Evo and iPhone. Now that's what I'd call a hybrid.

Ride safely,
Louis

Louis,

Hey, I could have been asking about my '76 shovelhead....


Dawg,

Thanks for the info.  I was just not sure that the two small holes in the two rocker box hollow bolts would let enough gasses pass without over pressuring the lower end, or upper end for that matter.

It would be cleaner if I could get away with only running the rocker box air cleaner vents.

I have one of the $15 breathers I picked up for the new project; one of the wire mesh with the chrome dome and the 3/8" hose barb at the other end.  I see these a lot on shovelheads and EVOs.  I guess if I had room and it looked okay, I could run both.

I've heard rumors about the upper rocker box vents puking lots of oil because of some sort of passage design issue on EVOs.  Don't most of them use reed valves of some sort to vent only on pressure and then close on the low pressure stroke?  Do these require maintenance from time to time?

Thanks again for the information.  I'll stick with the upper rocker box vents for right now and see what happens.

    

[djkak]

I have a quick question about crankcase venting.

On my new Ultima EVO style motor on my boardtrack project, I have an air cleaner with internal vent tubes one from each rocker box and leading into the carb/air cleaner throat.

I also have a crankcase vent fitting just above my oil pump.

If I run the rockerbox vents into the carb throat, do I still need to vent the crankcase?
I would prefer to NOT run the case vent if I don't have to, but I don't want to over pressure any of the seals.

So what are my options?

Boy, doing this from my iPhone, it takes a while typing.

Greetings Dan,

The vent fitting in the attached photo is used to vent the oil reservior and is required.

djkak

[Dan_Lockwood]

Greetings Dan,

The vent fitting in the attached photo is used to vent the oil reservoir and is required.

djkak

So I'll need to run a hose from that fitting up to the top of my oil tank somewhere?

Is that an Ulitma in the picture?  Looks just like mine.

You know, on my '76 FLH, I have three lines going to the oil tank.  One if for the oil return from the motor going to the filter inside the tank.  One is for a vent.  And the final one is for oil out to the pump to be used through the motor.

But my oil tank in that case is not vented to atmosphere.  It has a rubber temp gauge/fill level dip stick which is not vented that I know of.

On my new project I have the oil tank that will hold 5 qt of oil and have 1 qt oil free space for expansion etc.  I'll have a return line, an oil feed to the pump line and now the added crankcase vent line.  The cap I'm using on the oil tank is vented internally so that gets my tank vented.

Or should I NOT vent the tank and use the crankcase vent to the tank and then back through the rocker box breathers as my motor/oil tank venting?

I think I'm making a mountain out of an ant hill on this, but I'm just not up on my oil line routings.

I greatly appreciate the help and direction.

Thanks.

    

[djkak]

So I'll need to run a hose from that fitting up to the top of my oil tank somewhere?

Is that an Ulitma in the picture?  Looks just like mine.

You know, on my '76 FLH, I have three lines going to the oil tank.  One if for the oil return from the motor going to the filter inside the tank.  One is for a vent.  And the final one is for oil out to the pump to be used through the motor.

But my oil tank in that case is not vented to atmosphere.  It has a rubber temp gauge/fill level dip stick which is not vented that I know of.

On my new project I have the oil tank that will hold 5 qt of oil and have 1 qt oil free space for expansion etc.  I'll have a return line, an oil feed to the pump line and now the added crankcase vent line.  The cap I'm using on the oil tank is vented internally so that gets my tank vented.

Or should I NOT vent the tank and use the crankcase vent to the tank and then back through the rocker box breathers as my motor/oil tank venting?

I think I'm making a mountain out of an ant hill on this, but I'm just not up on my oil line routings.

I greatly appreciate the help and direction.

Thanks.

    

The photo is of an EVO Softail.

I’m not sure what you mean about the oil cap being vented internally, but if it is vented to the atmosphere there will probably be a fair amount of oil residue collecting around the opening of the vent when the machine is run. If I get a vote I would recommend venting the tank with a fitting high above the oil level and a line running to the pictured crankcase fitting in my previous post.

The reason for the vent is that the return pump has nearly 3 times the capacity of the feed side. Without an oil tank vent, things would get ugly in a hurry. I would be surprised to find a store-bought oil bag without provisions for a vent. If your application is a custom, do what you can to incorporate a vent fitting up high. At speed there is a fair amount of air and oil moving through this vent.

As long as we are talking about old stuff; the FLH vent line has a “T” near the middle which also serves to vent the Primary Housing. The first 1965 Electra Glide’s were manufactured without the Primary Vent which raised a little hell with the oil flow out of that housing. This vent line carried enough oil mist to work adequately as the front chain oilier on the FLT dry clutch models. With the advent of the wet clutch in mid ’84 production, the “T” was no longer used and the primary housing was vented through the transmission mainshaft via a flat on the clutch pushrod.

Good luck with your project, Dan.

djkak