2008 WR450f AIS removal hose routing

Im in the process of doing a topend on the WR and figured it would be a good time to remove the AIS.  Now that the bike is back together, I have confused myself on where all the hoses go.  I have capped the port on exhaust side and intake, but no sure how the hoses route.  I have one going from top of cylinder head cover back to what I think is the top air box hole.  I have a hose coming off the starter motor that I have no clue what to do with and a hole at the bottom of air box that I am not sure what goes on it.  Any help appreciated

Ive got a Y or T fitting mounted off the right side of the carb on my 08.  One goes from the valve cover, other from the  starter, and then one to the air box.

 

Im not sure which hose was eliminated with the AIS kit.  I just made my own kit.  On mine, I have the "top air box" hose blocked off.  Technically it would be the hose in the carb air boot.  Ive got my breather hose going into the air box before the filter.

Im in the process of doing a topend on the WR and figured it would be a good time to remove the AIS.  Now that the bike is back together, I have confused myself on where all the hoses go.  I have capped the port on exhaust side and intake, but no sure how the hoses route.  I have one going from top of cylinder head cover back to what I think is the top air box hole.  I have a hose coming off the starter motor that I have no clue what to do with and a hole at the bottom of air box that I am not sure what goes on it.  Any help appreciated

The hose going across the top of the head goes to the bottom of the air box, right next to/on top of the clear drain plug. The starter hose should go into. "Y" that is on the other side of the carb. The top air box hole gets capped.

Now that I think about this though, I have a question. The "breather" hose that is going to the bottom of the air box, does it suck any air in or does it push any air out?

Edit - if I remember it correctly, this is a oil breather hose and if the bike gets dumped upside down some oil could come out and that is why this hose goes to the "dirty" side of the air box.

Edited by kenshaw720

The hose going across the top of the head goes to the bottom of the air box, right next to/on top of the clear drain plug. The starter hose should go into. "Y" that is on the other side of the carb. The top air box hole gets capped.

That creates more questions.  Hose from top of valve cover goes to bottom of air box.  Hose from starter goes into Y fitting.  What other hoses fit onto the two remaining barbs of the Y fitting?

valve cover and starter motor hoses go to the Y piece

the third hose from the y piece goes to the bottom of the air box as it comes from yamaha and the port in the airbox boot having to be plugged (as this is what feed the AIS system)

Many (including me) re-route this third hose from the y piece to the top of the airbox boot (the old AIS port), and plug the port on the bottom of the air box

Edited by GuyGraham

valve cover and starter motor hoses go to the Y piece

the third hose from the y piece goes to the bottom of the air box as it comes from yamaha and the port in the airbox boot having to be plugged (as this is what feed the AIS system)

Many (including me) re-route this third hose from the y piece to the top of the airbox boot (the old AIS port), and plug the port on the bottom of the air box

So you in essence take what we have going to the bottom of the air box and re-route it to the top of the air box boot and then plug the bottom port?

 

Ok, got it.  Back to my original thought then, why is it they didn't do this in the first place?  Would oil come out of that hose if the bike was upside down or in any other precarious position?

Yes, after AIS removal, re-route the engine breather pipe to the airbox boot

 

Who knows why Yamaha did it this way

Suzuki DRZ400 engine vents to the air boot, via an oil collector box, but Yamaha vent the engine to the dirty side of the air filter

 

My concern was any water in the bottom of the airbox could get into that pipe, which lead directly to the engine and its oil, so I copied the Suzuki layout

 

The only oil that will come out is from the pumping of the engine, or if you over fill it

Yea, I guess it is whatever you are more comfortable with.

 

Not saying it can't happen but for me I can't see a situation where water would get in the hose and be carried up into the engine.  The hose goes along the carb, up over the top of the engine and down the other side to the "T".  While the bike is running there should always be positive air flow from it.

 

IMHO, I think there is a bigger chance of me falling on my head and the bike doing something weird and potentially having oil vent out and into the carb.  Do I think that will ever happen.  Nah, I don't think either of the situations will happen.  But since I have to connect it up, I am more comfortable with the dirty side of the carb.  

 

I just hope I am never in a situation that it becomes a "crap, I should have......" :foul:  :thumbsup:  :ride:

 

While the bike is running there should always be positive air flow from it.

 

 

 

Not entirely correct

You will get positive and negative air pressure in that pipe as the piston rises and falls

Edited by GuyGraham

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