# Question about airbox on brute force



## jyarber (Oct 27, 2010)

I was running all new vent lines tonight. I pulled the air box up on my 06 brute force. You have the one big crankcase hose. The smaller hose I guess that is suppose to be a drain and then one larger nipple with a piece of rubber attached to it. I put a nipple cap on the drain hose and zip tied it. What am I suppose to do with that other large one that has that rubber flapper piece on it?? I don't want any water getting in my air box. Did you guys leave in on there or what??


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## NMKawierider (Apr 11, 2009)

That's the ...what we call duckbill. The slight vacuun the box has on it is supposed to keep it shut and when the engine is off, it relaxes enough to let any water or oil drain out. Mine warped and sucked all the time so it got siliconed shut. I suppose a cap would work just as good.


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## filthyredneck (Feb 10, 2010)

As stated above....most of the time it gets siliconed shut from inside the airbox. 

I went a different route and removed the duckbill and replaced it with a heavy duty piece of clear hose that goes down to my belly skid... just hose clamped it to the airbox and put a valve on the bottom. Did this JUST IN CASE a little bit of water or somethin made its way in the box... I can look at my hose and always tell that my airbox is dry OR if somethin got in there somehow then I can drain it without having to lay the bike on its side. (Original reason for this was because my airbox lid wasnt sealed good and when I went over the lid deep it allowed a couple ounces of water to get in the box, but not enough to make it into the throttle body or down the crank vent. Man was it a P.I.T.A. to get that outta there with the duckbill sealed up)


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## jyarber (Oct 27, 2010)

Will RTV work and harden up?


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## NMKawierider (Apr 11, 2009)

jyarber said:


> Will RTV work and harden up?


Yep, I just cleaned it up inside between the flaps and used black RTV. Although filthyredneck's line & valve does give you a way to get the water out if you ever get some in...and you know that lid seal probably will leak sometime. I think if I was "go'n deep", that's what I'd do.


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## jyarber (Oct 27, 2010)

Are u guys sealing the airbox lid with rtv also or just using the factory gasket?


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## brutus750i (Nov 17, 2009)

jyarber said:


> Are u guys sealing the airbox lid with rtv also or just using the factory gasket?


 dielectric grease on the factory gasket an rtv in the flapper valve down below.


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## byrd (Jul 14, 2009)

i seal my lid with rtv, its a great precaution to something that can ruin ur atv and its easy to open and clean off when u need to get in it


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## jyarber (Oct 27, 2010)

Remove lid gasket then rtv it?


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## byrd (Jul 14, 2009)

yeah i removed my gasket but idk how everyone else does it


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## phreebsd (Dec 16, 2004)

regarding the airbox sealing:

if you use dielectric grease or marine grease leave the stock gasket on.
if you use rtv, remove the stock gasket.
regarding the duckbill, i filled mine with rtv and made sure it came out a little and then i put one of those paper clamps on it.


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