5/1/08 More Work on Teryx Air Box Mod - Kawasaki Teryx Forums: Kawasaki UTV Teryx Forum
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post #1 of 5 (permalink) Old 05-02-2008, 07:22 AM Thread Starter
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5/1/08 More Work on Teryx Air Box Mod

I got a chance to work on my air box mods again today. The out come is really good.

It will include main jets, diaphragm springs, needles, drilling a hole in each slide and the addition of two TPI valves in the air box.

The lighter springs in the diaphragms allowed me to open the air box some and put in larger jets. The hole I put in each slide allowed the slide to open quicker along with the lighter springs.

I tried a Jet kit from Dynojet and it didn't work the way I wanted it to. It would have worked fine without air box mods but it didn't work with the mod, the springs in that kit were still too stiff and the slides oscillated up and down but no nearly as bad as the stock springs did when I opened the air box. See when I opened the air box up I didn't have as much vacuum in the airbox so the springs wanted to keep the slides closed. When I say vacuum I mean it is just barely a difference in it and atmospheric pressure.

If some of this is baffling you then read our article about CV Carbs.


The point is with a stock Teryx with the exhaust tip out, a aftermarket CDI on there and this air box mod we went from 27 peak hp to 33 peak hp. and even a bigger jump in the 15 to 25 mph range.

If this is as far as you want to go then this kit is done except ordering all the individual parts from Dynojet since they don't come in kit form like we do it with the air box mods and bundling it with two TPI valves and doing the install video.

Next we will do this all over again with a exhaust system on there, which should just require bigger main jets.

Then we add cams and do it once more.

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post #2 of 5 (permalink) Old 05-02-2008, 09:39 AM
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This is an interesting find. Seeing as I do not understand the whole atmospheric pressure piece I will have to try to read up on just how the CV carbs work.

What exhaust are you going to be installing? I will be interested to see what your dyno results are after installing the exhaust. It will make for a good comparison as once I install the Muzzys (which will be here today...woohoo) I will be taking the machine to be tuned on the dyno.

Anything special you are doing on the dyno...locking the CVT etc? I am asking only as I want to attempt to do a true comparison and run them as close to the same as possible.

So let me ask this and see if I understand. By modifying the airbox you lose vaccum, when that vacuum is lost the slides to not operate propertly thus not running effeciently? So then is it safe to say that it is not an airflow issue? Would there be a benefit of keeping the stock airbox and simply doing an aftermarket air cleaner?

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post #3 of 5 (permalink) Old 05-02-2008, 10:20 AM
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Welcome todd!!
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post #4 of 5 (permalink) Old 05-02-2008, 01:28 PM
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This is some great info and glad you are here. I am going to put a few more hours on mine before these mods but this will help.

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post #5 of 5 (permalink) Old 05-02-2008, 08:46 PM Thread Starter
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With a CV carb you must have just a slight amount of vacuum inside the airbox or the slides won't work right. Try taking the lid off your Teryx and run it, it won't run right at all and it ain't cause the jets are off.

I will be getting a HMF two into one system and I guess I will buy a couple more duals from Muzzy and someone else to get a good comparison.

You really need to lock out the CVT but you are going to have to remove half the Teryx to get the CVT cover off.

The benefit to me is why buy a expensive air cleaner that will be no better than doing my mod and most likely those won't run right without a lot of fiddling.

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