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I don't think you need any step-by-step instructions to do this.

Take off the airbox; observe how the factory "snorkel" draws air from between the cylinders - ask yourself why Kawi did that; cut a hole in the front side of the airbox in an oval, two circles, or whatever other shape you think looks cool (make sure you understand how the air flows into the airbox and into the intake so you understand where to cut); clean up your mess; reassemble; ride.

Some guys trim the snorkel and put the seal piece around the newly cut hole. I didn't do that as I like the plain open hole in the front of the airbox. You barely notice it. Some others plug the factory hole in the back of the airbox to limit the amount of "hot air" getting into the airbox - I didn't bother with that as I figured the cooler air coming into the newly-cut hole in the front of the airbox had an easier path into the airbox that from the factory hole, meh...whatever.

I did this ghetto-mod myself - the only real noticeable change was hearing the intake a little more.

Well that is cool and all, it will not add X horsepower to the bike. Adding a K&N filter might open up the stock airflow a tad, maybe it'll add a HP or two based on the butt-dyno. You'll likely hear the intake a bit more with the K&N - or not - depending on how much other noise is going on around you.

Do not expect any miracle HP gains by doing this.

I have also done the partial debaffle to my stock pipes, so maybe the happy-meal (of the two mods together) has added 2.2356 HP to the bike - who knows.

Would I do it again? Yup!
 

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thanks

Any detail on the secondary plate?

ROmper
No walkthrough needed for this either. When you pull the airbox off and expose the throttle body, there will be two round plates mounted down in the shaft of the throttle body. I have not done it yet on this bike but on other bikes only one screw holds in each. You simply unscrew them and take them out. Be careful not to loose anything down the shaft. Shouldn't be much of an issue on this bike but the throttle body is vertical on others so it was an issue.

This again is a personal preference mod. On a dyno you may actually loose some low end with this mod. Each bike is different so all I can say is do your best not to strip anything out so you can reinstall them if you don't like the result.

Here are some pics of what it looks like Romper

https://www.facebook.com/photo.php?fbid=1385103953389&set=a.1385103553379.2059045.1405715559&type=3&permPage=1

Just click the pictures to cycle to the next one.
 

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You will also finds loads on info in this site about removing those secondaries. Some have removed them, and then re-installed them. Some are running without them. Some haven't bothered to remove them.

I considered this mod (removal of the secondary throttle plates) but decided against it.

Some have said that the removal of these plates makes the roll-on throttle response a little "jerky" or "sudden". If you think about it, at the end of the day these plates do not really restrict the WOT of the VN900, IMHO.

In theory, these secondaries will "richen up" the mixture for a second if one suddenly opens the throttle - as they lag the opening of the primaries by a wee bit - and restrict the incoming air just for a second (maybe less than an actual second). You get the idea.

I have not done the volumetric math in the entire intake tract (or the exhaust for that matter), but the possible volume of air that the bike can use "stock" (how fast the bike can ingest air) is lot likely restricted in the throttle body. I expect the smallest / tightest path of incoming air for the bike is the intake valve opening - although I could be wrong. In any event, in theory, the bike may be able to sneak a couple more CFM of air into the combustion chambers at WOT by the removal of the plates. In a perfect world, one would likely have to remove the shaft that those plates ride on as well, to make the throttle body the perfect shape for the incoming air. I do not know if you can even remove the shaft - I think it has other functions besides holding those secondary plates in place.

Like I said, I have not done this mod as I rarely operate the bike at WOT. And, of course, I do not have aftermarket pipes or intake yet, so the most restrictive part of the entire intake/exhaust tract is not those butterflies.

...just one opinion...
 

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I just did the mod. Took stock air cleaner off, removed secondary throttle plates, performed marble mod using a red wire nut and two zip ties, and installed my cobra CAI. Will post a few pics here shortly.
 

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Ok here are some pics. as you can tell you just peel off the layers until you get to the Sub throttle plates. Remove those and then either reinstall or put on an aftermarket CAI. I installed a Cobra. Haven't had a chance to run the bike, and I still have the other two pieces of the big 3 left to install, but it looks good that's for sure.

http://s633.photobucket.com/user/bowhuntmaster/slideshow/CAI Install
 

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thanks guys.

let me know how it goes darkarcher

romper
Started the bike up yesterday afternoon. I can tell the positive improvements without needing to take it down the road. Just twisting the throttle a little in the driveway I can feel that the lag is completely gone, yet it doesn't seem harsh or twitchy. That's coming from a sport bike owner where things are very sensitive so its relative I guess. It breathes so well now with the aftermarket CAI. Even if you don't take the secondary throttle plates out, get a CAI. I cant believe the stock box has this bike breathing the hottest air possible between the two cylinders! Only three complaints on this bike are the stock air box design, the fact you need to remove the radiator reservoir in order to adjust rear shock, and the fact you have to remove the rectifier to get to the oil filter. I guess for the price I paid though, I really cant complain. I am about to make another post about a startup behavior that is in no way associated so keep that in mind if you read my next post.
 

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Hi Dark Archer.
Interesting info.
BTW I do not need to remove the rad tank to adjust the rear shock, with the three parts of the adjustment tool assembled its really easy working around and above the tank, occaisionally flipping the tool over when needed. I know there has been a lot of talk of skinned knuckles etc, which makes me wonder ... are people trying to adjust the shocker without assembling the three parts of the tool???? The paint job is nice in your pics .
 

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Hi Dark Archer.
Interesting info.
BTW I do not need to remove the rad tank to adjust the rear shock, with the three parts of the adjustment tool assembled its really easy working around and above the tank, occaisionally flipping the tool over when needed. I know there has been a lot of talk of skinned knuckles etc, which makes me wonder ... are people trying to adjust the shocker without assembling the three parts of the tool???? The paint job is nice in your pics .

Thanks. I agree it may be possible to adjust without removing the rad tank. I didn't try it since it was my first time adjusting and I didn't know how much force would be needed. Like you said the trick is to assemble all three pieces of the tool to get the needed leverage. I went from 4 to six fairly easily. In full disclosure I was bleeding in two places when finished. Wear thick gloves and put something over that pointy bracket to the right if your going up a number.
 

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I did the DIY air intake over a year ago and I've been happy with it. When I rev the engine, you can hear the suction.
Plate 6" circle clean out plate from Lowes plumbing section. Includes center screw to attach filter

Acorn nut for center screw, 1/4 chrome w/washer, two 1/4 nuts to solidify post.
Gasket stuff 3/8" weather rubber, one sticky side.
Specter filter red
Specter Air breather hose filter*
*3/8" hose connector for breather hose filter
Blue liquid gasket? Optional. Probably better without it.
1-1/2" hole saw - be sure to clamp down plate, it cut me wicked.

Looks depend on the filter.*
Performance depends on accuracy of holes, seal.*

*Initially I didnt have much of a bend in the crankcase tube and while on a long highway ride at higher rpms, started to get oil spray on my bike. I modified the tube to have an upward bend. I havent had any issues since. *Mileage dropped from the 50 mpg to about 44-46 mpg depending on how much playing I do.*

Start it up
Red FI light should go off
Idle should be 1,000 rpm


Sent from Motorcycle.com Free App
 

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wocka, wocka, wocka
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Take off the airbox; observe how the factory "snorkel" draws air from between the cylinders - ask yourself why Kawi did that; Would I do it again? Yup!
everything is done for a reason, they dont do things just cause theyr bored.. tho it may seem that way often.. The Snorkel is on many intake systems as it helps to create "Laminar" air flow thru the throttle bodies and into the cylinders.. you can move more qty of air if its stable than if its turbulent.. poncho
 

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everything is done for a reason, they dont do things just cause theyr bored.. tho it may seem that way often.. The Snorkel is on many intake systems as it helps to create "Laminar" air flow thru the throttle bodies and into the cylinders.. you can move more qty of air if its stable than if its turbulent.. poncho
I agree they did it for a reason, but that reason did not have anything to do with making more power or moving more of anything. Stick a straw in your mouth and take off running. See how long you can breath through that before you pass out. There is definitely something to what your are saying. A properly designed air box will make more power than the "wide open" approach that most of the aftermarket CAI take for this bike.

That being said I would like to commend Kawasaki for doing an amazing job on this bike. Of the three bikes I have owned from new and the 6 or so different bikes I have ridden for any amount of time, this ties for number 1 for best stock fueling. If your buying the bike to ride two up, or don't care much about performance above 80mph, doing anything to the bike would be silly. It cant get much better for street riding. That's my 2 cents.
 

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wocka, wocka, wocka
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Stick a straw in your mouth and take off running. See how long you can breath through that before you pass out.
If your buying the bike to ride two up, or don't care much about performance above 80mph, doing anything to the bike would be silly. It cant get much better for street riding. That's my 2 cents.
900cc motor, can only draw specified cfm depending upon rpm and operating parameters. stock air tube is designed to furnish appropriate flow and keep it laminar. you may increase flow IF you change parameters such as intake pressure and/or exhaust volume. but just changing the path will not increase the volume.

btw, HP is not what you need for the kind of riding you describe. 2up is same as hauling a load. you need more tork. that is bottom end stuff. spinning motor faster doesnt get you there. It takes a Bigger Motor. with more torque.
that is the issue with 900's. have had plenty. theyr great bikes for solo and ez load work. they top out early and yor always ridding at the top of their output, wanting for more.
Get you a BIG motor that makes more Tork than you will ever need and you will always be in the money in any gear at any rpm at all speeds. the diff is illuminating. but you wont know that till you do it. or keep throwing money at that 900 trying to make it perform. dont take this wrong way, I have a lil 750 I keep trying to ride like a big boys bike.. it aint and never will be.. is why i have my v2k. poncho
 
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