Author Topic: engine decompression tube  (Read 4172 times)

JC

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engine decompression tube
« on: January 14, 2013, 04:25:32 PM »
It seems like my motor is blowing off some oil into the blowoff tube just below the airbox. I looked at the ncy engine decompression kit. Is this just a useless gimmick or will it help let my crankcase breathe? Some parts sites recommend using this with a bbk.  It seems like it would just shoot hot oil everywhere unless you put a catch bottle on the end. Anyone care to help/comment?

streido

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Re: engine decompression tube
« Reply #1 on: January 14, 2013, 09:32:41 PM »
It seems like my motor is blowing off some oil into the blowoff tube just below the airbox. I looked at the ncy engine decompression kit. Is this just a useless gimmick or will it help let my crankcase breathe? Some parts sites recommend using this with a bbk.  It seems like it would just shoot hot oil everywhere unless you put a catch bottle on the end. Anyone care to help/comment?

Yeah, they all do that. I just emptied mine every few weeks or whenever it needed it.

No idea on that NYC kit. My tube just hangs free to drip out under the scoot now since i fitted the open filter.
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wordslinger

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Re: engine decompression tube
« Reply #2 on: January 14, 2013, 09:35:36 PM »
..if you have a free-flowair intake filter, the th kit might be ok..


..i just looked at the kit...hhmmm...i dunno...

..replaces the dipstick...


..however, you may need to have some venting with a cylinder kit mod...might work fine!!

..and it's only like...$12.00...
« Last Edit: January 14, 2013, 09:42:44 PM by wordslinger »
..every mod (action) necessitates a (reaction) mod..

MotoRandy123

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Re: engine decompression tube
« Reply #3 on: January 14, 2013, 10:10:43 PM »
Is there lots of pressure in there or just sloshing?
2012 Yager GT 200I - Southern NH

wordslinger

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Re: engine decompression tube
« Reply #4 on: January 14, 2013, 10:18:00 PM »
...i would think the added heat  a cylinder kit creates would tend to cause more oil vapor...


..oem setup creates a "vacuum" at the valve cover...thats the tube that condensates oil vapor into the airbox...

..if you keep oem airbox, then probably dont need the ncy...

..positive cranckcase ventilation...some swear by it...
« Last Edit: January 15, 2013, 12:08:56 AM by wordslinger »
..every mod (action) necessitates a (reaction) mod..

JC

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Re: engine decompression tube
« Reply #5 on: January 15, 2013, 02:53:53 PM »
Is there lots of pressure in there or just sloshing?

My airbow blowoff tube has been pretty full the last 2 times I checked it and my oil level was low last time I checked it.

MotoRandy123

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Re: engine decompression tube
« Reply #6 on: January 15, 2013, 04:59:31 PM »
I noticed there is no PVC valve on these scooters, maybe adding one would help?
My old BMW had a labyrinth inside the airbox with a drain so the oil that got in there
went back to the crankcase. Maybe loose rings are allowing too much blow by and it
will calm down once they seat better?
2012 Yager GT 200I - Southern NH

wordslinger

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Re: engine decompression tube
« Reply #7 on: January 15, 2013, 11:39:53 PM »
My airbow blowoff tube has been pretty full the last 2 times I checked it

..how often was those times?

...i always lost oil in my 08 a50...but she performed...
..every mod (action) necessitates a (reaction) mod..

JC

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Re: engine decompression tube
« Reply #8 on: January 16, 2013, 12:04:00 PM »
It performs perfectly. It's a 2012 so I was just worried it was blowing off too much for being so new. I do ride it every day though. It seemed like I checked it every couple to few weeks recently.

TauEffect

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Re: engine decompression tube
« Reply #9 on: March 21, 2013, 06:33:21 AM »
I bought the PCV available at scrappydog.com...think it was like 10$...tried it out and my scoot was boggy from idle to about 25 MPH...then it wouldn't accelerate any further...the stock setup under the airbox is filled with a yellowish foam material and has a small vent hole right under the carb intake...can't seem to figure out how to eliminate that stock valve under the airbox without sacrificing performance...thinking it might have something to do with the intake air pressure generated from feeding the carb might be what makes that stock valve function

On a side note, i came up with a compromise for better airflow...i removed the stock air filter and intake snorkel and added a pod filter where the intake snorkel mounted to the airbox...nice deep resonating sound and weather tight
« Last Edit: March 21, 2013, 06:34:55 AM by TauEffect »
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Vivo

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Re: engine decompression tube
« Reply #10 on: March 21, 2013, 07:45:11 AM »
This is a breather hose... this replaces your bike's oil dip stick... the long hose is there to accommodate the oil that might splash out... works fine with me...






This other one has a catch can....


« Last Edit: March 21, 2013, 07:47:23 AM by Vivo »

JC

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Re: engine decompression tube
« Reply #11 on: March 22, 2013, 04:09:36 PM »
I bought the PCV available at scrappydog.com...think it was like 10$...tried it out and my scoot was boggy from idle to about 25 MPH...then it wouldn't accelerate any further...the stock setup under the airbox is filled with a yellowish foam material and has a small vent hole right under the carb intake...can't seem to figure out how to eliminate that stock valve under the airbox without sacrificing performance...thinking it might have something to do with the intake air pressure generated from feeding the carb might be what makes that stock valve function

On a side note, i came up with a compromise for better airflow...i removed the stock air filter and intake snorkel and added a pod filter where the intake snorkel mounted to the airbox...nice deep resonating sound and weather tight

You have pics of the new weathertight filter??

TauEffect

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Re: engine decompression tube
« Reply #12 on: March 24, 2013, 10:24:39 AM »
Lol...the filter isn't weather tight, just the configuration...if any water gets past the filter it doesn't make it into the intake tube to the carb, there's a stock drainage hole at the back of the airbox for excess water...its just as safe as a stock configuration in the rain but with better airflow with the removed stock air filter
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