Check your Airbox Valve

B Murr

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I've just changed the little duckbill valve that lives at the back of the airbox, it is designed to let water drain out from the airbox but to close itself when the air is beign sucked in through the airbox. It relies on the rubber to flex and close itself, I provisionally changed mine as my bike being 26 years old I suspected it might be after gouing hard. When I checked the old valve after removing it I could suck air through it easily, no hint of it closing no matter how hard I sucked air through it. The new one was a different creature in that it close off as soon as I sucked on it.

Cost is €20 from the main dealer here, [part number is 13721337162

I'm only putting this up as most of us will be oblivious to the fact that there is in effect a small hole in the airbox letting in dust and dirt which will go straight to the carbs unfiltered.

No need to remove the airbox to replace, simply push the old valve through the airbox and squeeze the new one in afterwards. :thumb2

I'm not sure bhow essential the valve is in the first place, I guess it could be just blocked off with silicone but I wonder what happens if you find yourself riding in a lot of heavy rain, will the airbox accumulate water?
 
I'm not sure bhow essential the valve is in the first place, I guess it could be just blocked off with silicone but I wonder what happens if you find yourself riding in a lot of heavy rain, will the airbox accumulate water?

I rode in the monsoon in Goa and the air box filled up even though the duck-bill was clear.
Does not make for smooth running:D
 
I rode in the monsoon in Goa and the air box filled up even though the duck-bill was clear.
Does not make for smooth running:D

That makes sense, especially if you weren't stopping for long as I'd reckon the airbox is in a near constant state of vacuum when bike us being ridden so the water doesn't get any chance to start flowing out through the valve.
 
Good catch. Something I must check out myself when I'm doing the next service (soon).
 
Some of use use the hole to run a hose from the oil breather to a catch bottle below the seat - one that pushes into the breather fits the hole nicely.
I am in the driest state in the driest continent so wont comment on water in the air box, but I suspect rain heavy enough to make a difference would probably flood the electrics first.
 


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