What nipple is this?

1360 Views 10 Replies 7 Participants Last post by dr_gallup, May 20, 2007

StuckInKansas

Discussion Starter · May 17, 2007

Now that I have your attention...

On the front of the airbox, under the SAI nipple, and pointing down. When I was taking off my airbox, this nipple had nothing attached, no cap, and was vented to the outside. What gets me is that it vents into the part of the airbox after the filter, thus letting in dust, moisture, etc. I want to know what is supposed to be attached to this? It may be for the evap. system on CA bikes, but I want to verify this. My dealer is not very mechanically inclined, and the service manual says nothing of it.

:wtf: ???

opcorn:

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Avi8or

· #2 · May 17, 2007

It is a third harmonic resonator to eliminate standing waves in the airbox which could affect the filling of cylinders at 200 rpm.

Dunno what it actualy is, could be a moisture drain. I just plugged mine off.

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Devious2xs

· #3 · May 17, 2007

I think Avi8or is correct about it being a moisture drain -that is easy to cap off.

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dfib

· #4 · May 17, 2007

Avi8or said:
It is a third harmonic resonator to eliminate standing waves in the airbox which could affect the filling of cylinders at 200 rpm.

Had me 100%

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BUCKET

· #5 · May 17, 2007

Noticed that on mine too,is it ok to block it off,it wont create too much pressure in the box,is it to release pressure,all these questions and more you will find answered soon in this post because i don't have a fn clue.It would be nice to get an actual answer from a dealer as to what it actually is.

opcorn:

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· #6 · May 17, 2007

Bucket said:
It would be nice to get an actual answer from a dealer as to what it actually is.

Hahaa! You think they know?? :gayaway:

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StuckInKansas

Discussion Starter · #7 · May 18, 2007

I have studied the box, and the service manual. I am pretty sure that it is for the CA evap system not present on 49 state bikes. Its not cool that it was unplugged from the factory, as the air it lets in is AFTER the air filter. Any dust or moisture that gets in that hole is going strait through the engine. It breathes into the same space as the SAI, in the front of the airbox. I don't see how plugging it can hurt anything, so thats what I'll do...

And the dealer is gonna be clueless on this one......TRUST ME...

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Devious2xs

· #8 · May 18, 2007

I am pretty sure the nipple is the return from the evap cannister.

But it pulls very little air. I ran the bike on the dyno (12 pulls) with a piece of masking tape covering it on the inside. Wipe the inside of the airbox down with acetone and fill the hole with black RTV - worked for me.

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Martin_R

· #9 · May 18, 2007

Straight from factory, from the people who designed the airbox (yes, I got a reply to an email inquiry - the only one I ever got straight from the horses mouth ;D): the nipple is the SAI moisture drain as the SAI pipe can lead heat to the airbox which will result in condesating moisture inside small front chamber of the box as hot air meets the barrier of fresh air coming through filter.

I asked about the same thing: "how come it is venting to the clean side of the airbox?". Answer was just that the minimal amount of dirty air is nonsignifigant.

I have had the drain blocked at the same time I removed SAI & related pipes and have had no probs with moisture collecting inside airbox etc.

If you insist on running SAI and are anal like me about cleanliness, you can always stick a piece of pipe with a filter on the nipple as it is just a water drain.

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StuckInKansas

Discussion Starter · #10 · May 19, 2007

:sign5:

Wow, good answer. I can't believe somebody actually got a response to an email! Thanx for the info. As my SAI will be gone, the hole is getting plugged.

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dr_gallup

· #11 · May 20, 2007

StuckInKansas said:
I have studied the box, and the service manual. I am pretty sure that it is for the CA evap system not present on 49 state bikes. Its not cool that it was unplugged from the factory, as the air it lets in is AFTER the air filter. Any dust or moisture that gets in that hole is going strait through the engine. It breathes into the same space as the SAI, in the front of the airbox. I don't see how plugging it can hurt anything, so thats what I'll do...

And the dealer is gonna be clueless on this one......TRUST ME...

I have an evap canister on my bike and it does not connect to that. If you look at the flow path it really does not communicate with the air flow path. But is is not really sealed off either. I filled mine with sealant. End of discussion.

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