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Discussion Starter #1
I'm thinking about designing a custom airbox for my KZ750H3. What I'm trying to figure out is the total area of access to air in the stock box. Under the filter cap is a plastic stem with a number of small holes in the sides. Other then the crankcase breather hose, are these little holes the total access to air that the filter has? I assume that the stem goes all the way through the filter, blocking off any other access to air. Is that right? Thanks!
 

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Obfuscation Engineer
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I'm thinking about designing a custom airbox for my KZ750H3. What I'm trying to figure out is the total area of access to air in the stock box.

Not enough :D


Under the filter cap is a plastic stem with a number of small holes in the sides. Other then the crankcase breather hose, are these little holes the total access to air that the filter has?

Yes , erm well kind of . Total inlet is actually the big vertical annular hole in the top .


I assume that the stem goes all the way through the filter, blocking off any other access to air. Is that right?

Actually the bottom of the filter rests on a foam seal on the floor of the airbox if I remember right .

Thanks!

No problem , the bill is in the mail
If you can find any way to expose the airbox inlet to frontal area w/o butchering the bike you did better than good . I'll give you an important hint here . At the local craft shop you will find styrofoam cores for wreaths , flower arrangements and the like . At the local boat shop you will find fiberglass resin . More later if you go this route :D

~kop
 

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itching to ride
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If you can find any way to expose the airbox inlet to frontal area w/o butchering the bike you did better than good . I'll give you an important hint here . At the local craft shop you will find styrofoam cores for wreaths , flower arrangements and the like . At the local boat shop you will find fiberglass resin . More later if you go this route :D

~kop
If you have built such a contraption and still have it I want to see the pics.
 

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Discussion Starter #7
After doing a lot of measuring and calculations, it appears that a custom box with an opening of 4-3/8" by 2", or if different space is needed, an opening of 3" by 2-3/4", using the same basic filtering materials, would provide the same amount of air access as the stock box. Then the opening could be made smaller or larger depending on the engine's reaction.

Anyone see a reason to disagree?
 

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GHOSTRIDER
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After doing a lot of measuring and calculations, it appears that a custom box with an opening of 4-3/8" by 2", or if different space is needed, an opening of 3" by 2-3/4", using the same basic filtering materials, would provide the same amount of air access as the stock box. Then the opening could be made smaller or larger depending on the engine's reaction.

Anyone see a reason to disagree?
Sounds reasonable to me Kat. :wink: Where the opening is located will affect performance to a degree and not necessarily in a bad way. The cooler the intake air, the more its density increases and that means more oxygen in the chambers and that allows more fuel to be completely burned and that leads to more horsepower. :wink: I would like to develop an intake that utilizes a ram air intake system kind of like a hyper-charger. One step below a turbo-charger.:wink:
 

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Discussion Starter #9
Well, my mind never stops, so I've been thinking about this some more, and I think I'm wrong. The only supply (barring leaks and what little comes in from the crankcase tube) of air for the box is the opening in the cap. Regardless of how much air can pass through the little holes in the tube under the cap, or the open space under that tube....the tube itself has a total area of 1.96" (or whatever in mm). If an opening of 4-3/8" by 2" is equal to what the filter arrangement inside allows by, it still can't pass any more air then the cap allows in!

So I got to thinking. One reason I was thinking about doing this is to create a little space under the seat for tools and custom wiring and such. Doing the math, it occured to me that a single pod with a 40mm inside mounting diameter would pass the same amount of air as the opening in the cap does. So I'm thinking now of cutting the square section off of the back of the box, covering it with some plastic sheet, and mounting a single 40mm pod to the back. I figure that it will give me the space I want, and pass about the same amount of air as the stock box, requiring no jet changes. The pod would stick a bit into the space I want, but not nearly as much as the original box section.

Does this sound like another of my crazy ideas?
 

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Navy Vet Search & Rescue
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Doesn't sound crazy but you eliminate some of the function that a box gives. Mainly to protect the filter from air turbulence an water.
 

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Discussion Starter #12
These CV's are nice and don't need rebuilding and I don't need fiberglass for the box, but thanks for the ideas.

StarGate, that's true, but it seems to me that a single pod feeding all the carbs through the box, and dead centered at the back of the box (at least 5" from any side edge) would not be very much effected by turbulance-particularly if I put plastic balles to each side, and the seat would protect it as much as possible from rain (which I rarely ride in).

I'll do it and report if it works. And yes, if it doesn't!
 
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