Airbox modification for crankcase vent hose

I ride a '99 YZF400 which I have modifiied for woods and trail riding. I stuck the bike in a hole a couple of weeks ago midway up the engine and got water in the oil. I have been told in the YZF forum that I need to re-route my crankcase vent hose from under the frame up to the breather housing.

I figured one of you guys in the WR forum might be able to help me out and explain the best procedure for this? I don't have a problem with re-routing the hose, I just don't know how to attach it to the airbox housing. Do I drill out the housing and silicone in place or maybe T into the airbox drain hose?

Any comments are appreciated.


Do a search in this forum for "vent hose". There has been lots of discussion in the past about this particular mod, and the best way to do it. That's what I did to research it before making this mod on my '04 WR450. There are several ways to do it, and several of the posters expressed pros and cons for different methods. Do the search and you'll see what I mean. :)

There are a bunch of ways people have done it. This is the route I chose.

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