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Airbox removal ZXR250/ZR250

Discussion in 'Kawasaki 250cc In-line 4's' started by TwystedThrottle, Feb 26, 2014.

  1. TwystedThrottle

    TwystedThrottle Loud noises make me happy

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    Ok, I've been looking at doing a custom airbox removal on my Balius for a while now. I've been looking at ways to get individual air filters bolted onto the tops of the carbs. There is a problem however, the airbox directs filtered air into the carbs via 4 ram tubes which bottom out at the entrance to the slide housing. I can easily replicate this with an alloy tube through a custom made flange that bolts to the top of the carb. But the airbox also allows air at atmospheric pressure to enter the two areas around the ram tubes (where the brass ports are).

    What do these ports do? And what would happen if they were to be sharing the intake air to the throttle body?

    Cheers
     
    TwystedThrottle, Feb 26, 2014
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  2. GreyImport

    GreyImport Administrator Staff Member The Chief Contributing Member

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    They would be the pilot air jet and the main air jet ...?
    The other rectangular opening opposite is air for the diaphragm (correct me if Im wrong)

    Do you know what you may be up against by changing the air intake dynamics ?

    Heres what it all looks like (assuming the Balius is the same setup as the ZXR?)....

    ZXR carb.jpg ZXR airbox 1.jpg ZXR airbox 2.jpg
     
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    GreyImport, Feb 26, 2014
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  3. TwystedThrottle

    TwystedThrottle Loud noises make me happy

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    I've already got the whole thing apart and been measuring it all up for fit, I'm not after any gains in power, just a unique sound and look.

    You'll notice how the air rams in the air box bottom out on the body of the carby, so how would those jets deliver fuel to the intake air with the ram in the way?
     
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    TwystedThrottle, Feb 26, 2014
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  4. GreyImport

    GreyImport Administrator Staff Member The Chief Contributing Member

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    Well because u are changing the air intake you may find you will lose power or have other running problems
    Go for a ride around the block with no airbox and it may give u an idea on what to expect.
    Have a look here also ...

    Typical changes that require rejetting are air filter and/or exhaust because they lean out the engine..

    http://www.jetsrus.com/FAQs/FAQ_rejetting_101_how_to_rejet.htm


    Those jets are for air not fuel

    The pilot air jet forms part of the idle jet system. Air pilot jet is a type of the air metering system or air bleeding system. The air pilot jet regulates the amount of pressurized air drawn into the pilot system. This air pilot jet corrects the air and fuel mixture ratio. It improves fuel atomization, which is the process of turning fuel into gas.

    Read more: http://www.ehow.com/about_6646479_carburetor-pilot-air-jet_.html#ixzz2uOTN21XF
     
    GreyImport, Feb 26, 2014
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  5. TwystedThrottle

    TwystedThrottle Loud noises make me happy

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    I wish I could mate, suspended license means the bike is in a million pieces having a complete overhaul. I'll give it a go anyway seeing as I already have the designs drawn up. If it fails, I can always go back to the big, ugly airbox.
     
    TwystedThrottle, Feb 26, 2014
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  6. Frankster

    Frankster Grey Pride...Adventure before Dementia Staff Member Premium Member Ride and Events Crew

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    You might find Grey is right about losing power overall. The velocity stacks built into the airbox help compress and accelerate the air being drawn into the carbs. Removing the airbox will nullify this affect and probably make the bike sluggish and run rich. If you're going to replace the airbox with pods it would be a good idea to try to use something that includes a stack with the pod. Unfortunately, those ugly airboxes have a purpose other than filling up space.
     
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    Frankster, Feb 26, 2014
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  7. GreyImport

    GreyImport Administrator Staff Member The Chief Contributing Member

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    Definately give it a go ... half the fun is trying ..... and as u say keep the original setup to fall back on if all else fails :thumb_ups:

    I remember reading (but forgot to save it) that having a curved tube or a stack as hanging describes above , helps to direct the flow of air better into the carb from the pod or open type of intake.... something like that.

    Post up some pics of what you do !
     
    GreyImport, Feb 26, 2014
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  8. TwystedThrottle

    TwystedThrottle Loud noises make me happy

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    No worries, I'll take photos as I make the intakes up, so if it works, maybe it'll catch on. Patent Pending
     
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    TwystedThrottle, Feb 26, 2014
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  9. Frankster

    Frankster Grey Pride...Adventure before Dementia Staff Member Premium Member Ride and Events Crew

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    Good idea. I was going to take a mold of the standard velocity stack and give it to some 3D printing guys to see if they could make them to suit. On the ZXR250 there are some odd mounting points for the airbox over each carb, so a 3D printer could probably make these in one unit. Let us know how you go.
     
    Frankster, Feb 27, 2014
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  10. Th3_Huntsman

    Th3_Huntsman Senior Member Contributing Member

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    GI how'd this thing rev because from the top they look pretty dirty?
     
    Th3_Huntsman, Feb 28, 2014
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  11. GreyImport

    GreyImport Administrator Staff Member The Chief Contributing Member

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    GreyImport, Feb 28, 2014
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  12. Th3_Huntsman

    Th3_Huntsman Senior Member Contributing Member

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