650L valve cover breather question?


7 replies to this topic
  • award900

Posted September 13, 2006 - 09:52 PM

#1

What is the best way to vent the cover? Is it supposed to go all the way to the airbox, like the cranckcase breather tube does? How do you guys do it?

  • XR650L_Dave

Posted September 14, 2006 - 07:39 AM

#2

What is the best way to vent the cover? Is it supposed to go all the way to the airbox, like the cranckcase breather tube does? How do you guys do it?


???

You mean the tube that goes from then head up to the oil resevoir?

Dave

  • LotsOfBikes

Posted September 15, 2006 - 12:23 AM

#3

Yeah that tube goes to your intake manifold where your brake booster, environmental controls vacuum source, and your vacuum activated transfer case selector for your 4-Wheel Drive hooks up. While you have your hood up, replace the PCV valve with a Bosch.

I'm putting the Newcastle Ale down now. :applause:

.... yeah what Dave says..

That tube on the top of the valve cover on your 650L goes right up to the frame. It is a breather tube that allws air to move in and out of the frame as needed. If the tube is pluggged off, oil flow would be disruped as it is trying to go into, and pass out of the frame.

It's secondary purpose is that it gives somewhere for your oil to go when you are filling the oil up to the proper capacity after an oil change, without having to actually start the engine.

It also serves the tertiary puropse of giving your oil somewhere to go when you have put slightly too much oil in the bike.. Been there, done that... :applause:
:thumbsup:

:applause:

  • XR650L_Dave

Posted September 15, 2006 - 08:00 AM

#4

Yeah that tube goes to your intake manifold where your brake booster, environmental controls vacuum source, and your vacuum activated transfer case selector for your 4-Wheel Drive hooks up. While you have your hood up, replace the PCV valve with a Bosch.

I'm putting the Newcastle Ale down now. :applause:

.... yeah what Dave says..

That tube on the top of the valve cover on your 650L goes right up to the frame. It is a breather tube that allws air to move in and out of the frame as needed. If the tube is pluggged off, oil flow would be disruped as it is trying to go into, and pass out of the frame.

It's secondary purpose is that it gives somewhere for your oil to go when you are filling the oil up to the proper capacity after an oil change, without having to actually start the engine.

It also serves the tertiary puropse of giving your oil somewhere to go when you have put slightly too much oil in the bike.. Been there, done that... :applause:
:thumbsup:

:applause:



I know my bike is not overfilled, and oil *always* comes out that hose and into my oil resevoir, since new.

Anyone know the oiling of these beasts enough to say what that critter is for, and what the expected behavior is?

Dave

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  • cleonard

Posted September 15, 2006 - 08:20 AM

#5

I believe that it's primary purpose is pressure equalization. With the frame tank closed very little oil should go thru it. It just lets air in and out as the oil level in the frame reservoir changes. When you open the oil filler/dipstick, it is now open to the air and it will carry some oil from the head since it is splashing around in the head.

The engine vent is on the crankcase.

  • LotsOfBikes

Posted September 15, 2006 - 12:08 PM

#6

Dave,

If you've had your valve cover off, you will notice that the tube litterally enters through the top of the valve cover. If you, as you stated above, alway have oil travelling UP that tube (from the valve cover to the frame), then that would mean that your engine is entirely filled up to the top of the valve cover in oil.. Not a good thing with a dry sump motor.

I doubt this is the case.

As both Cleonard and I have stated it is for pressure equalization for the oil that is in the frame. If you were to plug off this tube, then you could possibly disrupt the capability of the oil pump to effectively produce enought oil to the engine, and still keep the sump dry.

The crank case breather on the 650L goes from the top of the transmission to the air box.


My 1995 650L just passed 60,000 miles :thumbsup:

  • award900

Posted September 16, 2006 - 10:10 AM

#7

Thanks Dave! I recently purchased a new motor for the L, after it had been sitting for over a year, and couldn't figure out where the thing goes! The oil line was pushed up , next to the wires, under the gas tank the whole time. I took the bike out for a spin, without that line hooked up, and oil definitely comes out of the top of the cover. Not flowing out but it does leak out.
The dealer said my old motor had lost oil pressure. I thought maybe I had put the oil filter cover on without lining up the tabs. Could that cause oil pressure to drop?
Thanks again Dave. To get a reply from "That Dave" is kinda like speaking with Royalty! I'm not worthy! I'm not worthy, Alex.

  • LotsOfBikes

Posted September 17, 2006 - 01:11 PM

#8

XR650L dave is the BEST source!!!

I'm only a source of stock jetting, high mileage, absolute abuse, broken frames and burning oil.. And a few Richard Thorwaldson perfect welds here an there.

My bike is only a shining example of how tough these bikes are.

Daves bikes is an example of an Awe inspiring piece of equipment that sees less than 8000 miles between oil changes, and less than a year between oil filter changes :thumbsup:





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