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docc

crankcase vent return line

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I have had the funkiest intermittent leak of something that looks like "PB Blaster" that I thought was coming from the tank vent/overflow. Turns out it is coming from the crankcase vent return line. It is tight. And re-tight.

 

Is there any hope when these start to weep?

IMG_6702.jpg

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I’d rather replace than over-tighten... it seems some might have a stainless nipple (male) with same threads either did and others (my 02’) have a zinc chromate coated nipple with different threads on either side.

Harpers has em, you just have to clarify which one you have.

 

There is also a sealing washer that every good v11 owner has a few in hand I’m sure.....

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As I typed this I realized why I replaced the nipples on mine. They were the zinc chromate type and were flaking, so ignore my last post and get yourself the correct sealing washer and your mother has a brother named Robert.

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I was hoping it would be the sealing (crush) washer, but looks to be weeping from the "flange fitting", itself (?)

 

All this nipple talk gets me worked up, so I "re-seated" the hose fitting (loosened and tightened and repeated until I cranked it down right-well).

 

If there is a nipple in there, it should be impressed by now! :o

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Are you sure the leak is not coming from the crankcase breather hose (which is also in the picture I think?).

Mine coughs up some watery/mayonaise like drips from that on a cold start. Same colour.

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For  long while, I thought the leak was from the small rubber open hose (my combined fuel tank vent and tank over flow). In this image, I have cleaned it all up, applied foot powder and ridden 25 miles/ 40 km.  The leaks are barely visible at the joint and mouth of what I believe is a flare fitting (?)

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We are dealing with my crotchety memory here, but it "seems" like it was an AN fitting when I had the pan off last. If so, "She's dead, Jim.."

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Not sure what an AN fitting is. But, you’re saying once they start leaking, it’s time for a new line?

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Not sure what an AN fitting is. But, you’re saying once they start leaking, it’s time for a new line?

 

AN is just a standard for fittings.

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Not sure what an AN fitting is. But, you’re saying once they start leaking, it’s time for a new line?

 

AN is just a standard for fittings.

 

So, am I right thinking it is some kind of a flared line in there? Mates up to the nipple czakky mentioned?

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That's pretty much it. more than likely a crack.

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AN fittings are an old standard. AN comes from Army Navy as I understand it.

And they are a standard tapered fitting.

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AN fittings are an old standard. AN comes from Army Navy as I understand it.

And they are a standard tapered fitting.

 

 

AN Fittings

1187_ArticleSection_S_e5201523-7e8a-4df9

AN fittings, also known as Army/Navy, were originally developed as a military standard that dates back as early as World War II. A fitting listed at – 3 (dash three) refers to the inside diameter of the fitting, for instance a – 3 AN would fit a metal tube outside diameter of 3/16-inch. You will also notice that the size increments are 1/16-inch apart. All of the AN fittings that Speedway offers will feature a 37* tapered flare. The chart to the right and below will show some of the common AN sizes along with the closest national pipe thread size (NPT). Note that AN fittings and NPT fittings will not work together.

 

https://www.speedwaymotors.com/the-toolbox/automotive-fittings-explained/28780

 

Something I did not know. Thanks!

 

Also:

 

 

 

NPT threaded fittings require the use of a tape to create the seal, whereas AN fittings do not. When using an NPT fitting, it is common to only get a few turns tightening the fitting. This is because the thread is tapered and is not meant to thread all the way in – excessive tightening will NOT make a better seal, but can damage the fitting.

 

https://nicoclub.com/archives/automotive-plumbing-hoses-fittings-explained.html

 

So we need to know if on the Guzzi it's NPT or AN. Kinda important. We trust @docc with disassemble his bike this week and report back.  :notworthy:

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So, the fitting is not NPT, for certain.

 

I was hoping to wait for the next oil change to remove the line. As always, thanks to you folks for the insight and education! :thumbsup:

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