Cam Breather Pipe Re-positioning

a PCV valve is known as a check valve.

Never having taken one apart, I do not know what they look like inside. There are hang open checks and spring loaded checks. Some check valves require a certain position to operate, i.e. completely horizontal.

Pretty sure your std. PCV is spring loaded, all position.

The question is:

"Is there sufficient vacumn to suck water up 1m of vent pipe" :)

Interesting thread guys.

If a PVC valve is used, what about the blowby oil. Will it get trapped by the valve?

the answers were there, before your questions were even asked

No they were not. :) My question was whether or not the only point of not routing the hose ONLY to the airbox was to keep the oil vapors out of it. I guess you could infer that from some of the posts but I wanted to make sure that that was the case. I would think that most people would rather clean the airbox out when theyre cleaning the filter anyway rather than having an extra hose hanging off their bikes.


If you possibly submerge your bike (and airbox), the water (hopefully most if not all of it) will go ALL THE WAY DOWN the vent, not just drain DIRECTLY into your engine. :)

I drowned my 450 the first ride when it stalled in a creek.Go to this web site for the breather to air box mod. and follow the links to the dirt bike section.I did this and have since stalled in creeks without any problems.The mod has had no other bad affects . ( IT WORKS )


I did this mod as well (from offroad). It does function correctly, however, I would remove the airbox before drilling a hole. Also make sure you are far enough away from the cover mount that the fastner doesn't hit the new tube. I am going to take it all apart this winter and find a fitting that has rubber washers and a nut that holds it together. The oil vapor combined with cleaning has made the silicone turn loose. You might try roughing up the airbox with some sandpaper or dremel to get a better bite.


While removing AIS,I wanted to re-route breather ala YZ only to help keep airbox clean(er).After researsh on TT, Not so simple.

This is what I decided on, After a hard look at pros & cons.Remove from air box and plug box,re-route to front over valve cover L-side,cut-in at high point a 1/2 x 3/8 tee,cut-in and route YZ oem tube downstream,cut-in and route 3/8 tube up to where gas vent at 3-clamp head.

Now keep in mind plumbing is 2007,So flow exits valve cover to rear,then down to Y and kills back into motor to reclaim oil.On the branch side of the Y the tube returns up to where tee is cut in.This should make it difficult for oil to make its way to tube end at under L-side frame,While the 3/8 tube should break any vac(suck) situation.Yes No ?

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