How to disable flapper valve and smooth intake

[Badger]

This is a how to for those that are interested in doing this mod on 04 onwards bikes, i have done it on my track bike to allow more air and smoother air flow into the airbox, these bikes need as much as you can get in there, there will be some small gains regarding power, just don't ask me how much!!

First remove front fairing sections to get access to the intake housing

http://i3.photobucket.com/albums/y61/smokinrsvr/this%20n%20that/8010.jpg

http://i3.photobucket.com/albums/y61/smokinrsvr/this%20n%20that/8012.jpg

the removed intake

http://i3.photobucket.com/albums/y61/smokinrsvr/this%20n%20that/8011.jpg

split the intake taking note of all screws and fitting locations, the brass looking thing at the top of the pic is the flapper valve

http://i3.photobucket.com/albums/y61/smokinrsvr/this%20n%20that/8013.jpg

remove all the raised sections using whatever tools you have to do the best job, i used a Dremel and a nice sharp wood chisel

http://i3.photobucket.com/albums/y61/smokinrsvr/this%20n%20that/8014.jpg

http://i3.photobucket.com/albums/y61/smokinrsvr/this%20n%20that/8015.jpg

clean everything so you have no edges, rub down with fine sandpaper if need be, you don't want sharp edges or anything that will cause more turbulence, so get it clean and smooth

http://i3.photobucket.com/albums/y61/smokinrsvr/this%20n%20that/8016.jpg

http://i3.photobucket.com/albums/y61/smokinrsvr/this%20n%20that/8017.jpg

fill the flapper valve recess with silicone and smooth to give a nice flat surface, also build up silicone to block of the unused chamber as can be seen at the top of the picture

http://i3.photobucket.com/albums/y61/smokinrsvr/this%20n%20that/8018.jpg

do the same on the other side with silicone

http://i3.photobucket.com/albums/y61/smokinrsvr/this%20n%20that/8019.jpg

so when you put the two faces together you have the chamber blocked with a nice smooth surface

http://i3.photobucket.com/albums/y61/smokinrsvr/this%20n%20that/8020.jpg

looking through the smoothed intake

http://i3.photobucket.com/albums/y61/smokinrsvr/this%20n%20that/8021.jpg

the view of the flapper valve recess from outside the intake

http://i3.photobucket.com/albums/y61/smokinrsvr/this%20n%20that/8022.jpg

finally put it all back together, not to forget putting the sensor back in the intake

http://i3.photobucket.com/albums/y61/smokinrsvr/this%20n%20that/8023.jpg

A bit of a fiddly job, but should not be to difficult, hope this helps some of you in the quest for more power, and all at no cost, but watch your digits with all those sharp tools now :thumbup

[Posh Johnny]

Nice work Badger, thanks :thumbup

[DaveRSV]

I've noticed the flapper valve gadget on my bike Badger and often wondered what it was. My thought was that it was some sort of air pressure sensor for the ECU. So what does that flapper do exactly?

[DaveRSV]

I've noticed the flapper valve tucked down in my fairing Badger and assumed it was an air pressure sensor for the ECU. What does the flapper valve do exactly? Restrict the air flow below certain RPM?

Nice 'How To' mate :thumbup

[rsvchris]

Hi Badger,

That is a really well written/illustrated and informative thread:thumbup

What sort of power increase do you get by taking the flapper valve out?

I presume they fit the flapper valve to meet noise & emission testing?

Cheers
Chris

[bbstevebb]

Nice Job, thanks Badger

[deadhand]

What is the purpose of the flapper valve? Does it enable faster warm up from a cold start?

What are (if any) the disadvantages to doing this mod?

[Badger]

What is the purpose of the flapper valve? Does it enable faster warm up from a cold start?

What are (if any) the disadvantages to doing this mod?

This i have done on my track only bike, i would not bother for the road as any advantage is minimal, but on track every pony counts:thumbup

[Wes]

I've heard placing a screw in the vacuum line that connects to the flapper valve also disables it. Doing this alone, will any power gain happen?

[Badger]

You may well gain 1hp or two at the most, nothing you will notice, Homer Ewe airbox kit recommend this in their fitting instructions when fitting their kit, it's a two minute job:thumbup

[killaprilla]

badger - do you remove all the piping work and cap off the pipe at the throttle body ? am thinking of this mod as gonna be doing airbox mod so thought might as well get best air flow

[Badger]

badger - do you remove all the piping work and cap off the pipe at the throttle body ? am thinking of this mod as gonna be doing airbox mod so thought might as well get best air flow

No, if you look down towards the headlight cowling on the right you will see the valve housing, the brass coloured thing that looks a bit like a horn, take of the pipe shown in the pic and insert a ball bearing or bolt etc to block the pipe completely, that is it:thumbup

http://www.apriliaforum.com/forums/attachment.php?attachmentid=6600&stc=1&d=1076146049

[killaprilla]

ah right - nice one , thank you - might whip from end off 2mrw and get the old dremmel out :)

[Badger]

ah right - nice one , thank you - might whip from end off 2mrw and get the old dremmel out :)

Well, did you get the Dremel oot mate:dunno