River crossing - anti-water air filter mod?

2 replies to this topic
  • thefex

Posted April 07, 2014 - 04:34 AM


hi everyone!


I`m riding my YZ450F '08 both in MX and enduro, so I need to modify it a bit to meet such requirements.

The thing that stopped my engine last sunday was excess water that got into the airbox and made the air filter very, very wet... While riding in the forests I had to take the seat off, wring the air filter (it was wet as hell) and dry it out using warm exhaust fumes.. No harm to the motorcycle though..

here`s how it looked

How to prevent stalling the engine due to water?
Any ideas how to modify the airbox?
I searched the forum with no results.. maybe I missed something.. please provide links if such topics were discussed here. If not - show your airbox mods!

Thx and good riding everybody!!


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  • grayracer513

Posted April 07, 2014 - 06:54 AM


Not sure about the air box, but do these two things:


Find a half inch 'Y' fitting and place it in the breather hose in the down-sloping portion near the front of the cylinder head.  Route a second hose from here to the air box.  This will prevent the breather from being able to suck water up from the bottom when stalling or restarting in water. 


On the carb, find the two vent hoses that run up, over, and down and pull them out of the guide behind the engine.  Route them up into the air box, also.  That will prevent a vacuum from forming in the float bowl when water closes off the other vent hoses, and help keep the engine from stalling.


Going to have to figure out how to keep the air box drier, though.  Note that the YZ brings air in at the rear of both side panels, and the back edge of the seat.

  • ekulb14

Posted April 07, 2014 - 06:02 PM


humm, just thinking about it. i would try plugging the air intake on the sides with some porous foam, too keep water from splashing in by the bucket load. 

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