# Sealed Airbox Popping?



## Bacon (Jul 14, 2011)

After a bit of research here on the site I got down to business making my '11 Brute 750 into a water "proof" boat-on-wheels. Rerouting vent tubes, greasing electrical contacts and sealing up everything with silicone or dielectric grease... my brute can now handle some extensive swimming around in the creek without my belts and what have you getting soggy. Everything was going great for the most part. For the most part... Until after a few hours of hard use out of the water on the trail, my air box popped the seal I made with dielectric grease and the stock gasket. In addition it spewed some milky looking greasy substance that looked like the filter grease I used to seal the filter to the housing after it's last cleaning...
Nothing really came of it, even after putting a few more hours on the bike the only difference was that I had to keep the water level below the airbox. Is this normal? I know the airbox creates a vacuum when sealed but what would make it pop like that and what can I do to fix this problem? Should I remove the factory gasket and just use some rightstuff for a stiffer, more secure seal?:1zhelp:

Thanks in advance for the help!

_~Bacon_


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## Bacon (Jul 14, 2011)

It also might help to note that this past weekend when that happened it was well over 100 degrees around these parts.


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## arky man (Apr 6, 2011)

Sounds like it my be backfireing thru the intake I believe that means running rich. What size snorkle did you use for the intake? If you used 2 in thats prob what it is doing just switch to a 3in snorkle or you may need to get a programer for the fuel injection. Thats my 2 cents maybe someone with the same bike has had your problem and will offer more input


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## phreebsd (Dec 16, 2004)

have you checked your oil ?


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## Bacon (Jul 14, 2011)

phreebsd said:


> have you checked your oil ?


Forgive my ignorance but what about the oil would make it backfire into the airbox like that? Just would like to know for future trouble shooting reference.

I did sink the bike a while back but went through the motions of draining the bike and changing all the fluids (multiple times in the oil's case). I did check it just after it popped because of the consistency of the fluid that came out of it looked something similar to the milky oil you get after water gets into the reservoir. The oil turned out to be fine, still clear from my last change in fact as well as the proper level.

Little more info on the bike: other than the minor precautionary measures I've taken to prevent water from getting in to certain areas the bike's stock. (No snorkel)
This past weekend was also the first time I've taken it through anything deep since I sank it. Bike's got less than 50 hours on it as well.

Another note. I was rather generous with dielectric grease on the contacts, could this effect the response from the stock efi controller in any way?


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## Bacon (Jul 14, 2011)

May be confusing this problem with another...

http://www.mudinmyblood.net/forum/showthread.php?t=13472

Still would like to know why my box popped (and about greasing contacts) but the thread above sounds similar to what happened to me seeing as how i did kindve get splattered like the gentleman in this post.


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## Polaris425 (Dec 16, 2004)

Yeah it doesnt take musch D-Grease... just a dab... it's not a good conductor so too much can actually prevent current through the plug... 

I think PhreeBSD meant check your oil to see if it was milky?


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## Bacon (Jul 14, 2011)

Bacon said:


> The oil turned out to be fine, still clear from my last change in fact as well as the proper level.


I'm aware that oil does sometimes make its way in to the air box which is one of the reasons I was concerned and checked it after it happened. (saw the thread concerning a mod that prevents this from happening too but it seems a bit too labor intensive and technical for me at this point I think).

Gonna reseal the box, clean up the contacts a little with a cotton swab and be a little more conscious about riding in 4 wheel at speed and see if I have any more problems. Thanks for ya'lls patience with my inexperience ^^; kinda learning on the fly here.


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## Bruiser (May 21, 2011)

I just used clear rtv to seal my air box


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## filthyredneck (Feb 10, 2010)

Bruiser said:


> I just used clear rtv to seal my air box


Yeah same here... I gave up on the factory gasket & grease idea a long time ago, seemed like I'd always get a little water in the airbox when ridin DEEP for long periods of time. Plus the gasket finally broke in half on me so went to RTV silicone. Only downfall is that it makes it a bit tuff to remove the airbox lid if you need to, and is no longer water-tight once you do, so you have to re-seal it each time. I took the extra time to install a long clear drain hose with a valve on the end of it to my airbox where the duckbill used to be, runs all the way down to the skid pan....figured this way if something gets in there it'll go straight down my drain where I'll be able to see it, and if I ever notice liquid then I'll also know that somethings not sealed anymore or I've dunked the snorks.


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## brutemike (Mar 23, 2010)

sounds to me like your front diff puked oil out on top of airbox lid so check the front and rear diff for milked oils. I hope you got snorkes to i run the 3" on my 11 and never had a problem and another thing did you seal up the front of the airbox i hope not just make some snorkeles because if you dont have like i said above you need them or your far from water proof.


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## Bacon (Jul 14, 2011)

brutemike said:


> sounds to me like your front diff puked oil out on top of airbox lid so check the front and rear diff for milked oils.


This is why i need to keep coming here... lol. :34: I'm assuming this is what phreebsd was talking about. Just drained it today and as it turns out, YOU WERE RIGHT! Id wager you guys probably just saved me a lot of money in the future.


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## RedNeckBlueCollar (Feb 8, 2011)

Same thing happened to me not too long ago


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## brutemike (Mar 23, 2010)

Bacon said:


> This is why i need to keep coming here... lol. :34: I'm assuming this is what phreebsd was talking about. Just drained it today and as it turns out, YOU WERE RIGHT! Id wager you guys probably just saved me a lot of money in the future.


 Get some snorkeles on it to.:haha:


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## oft brute (Jul 22, 2011)

i've been doing this to seal my lid and it works great. spray wd40 or even cooking spray lightly on the seal ring on the lid then silicon it. soooo....... mutch easier to take back off.


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