breather hose RE routing ??

[ThumperKid250F]

hey guys i want to re route my breather hose into my airbox but im not really sure of how to do it.. do i drill a hole in my airbox and then seal it or is there another way. also if somebody has pics of this that would be great..

BTW i did a search and i couldent find anything or im not useing the right words.

bike 2006 yz 450

[AZ Thumpdaddy]

https://www.thumpertalk.com/forum/showthread.php?t=706602

[ThumperKid250F]

https://www.thumpertalk.com/forum/showthread.php?t=706602

is that the best way to do it?

also just a quick question but if you put a filter on the end of that hose wont it get full of oil and then wont let it breath?

[grayracer513]

You will need to service the filter occasionally, yes.

[ThumperKid250F]

You will need to service the filter occasionally, yes.

ok so what if i dont use a filter and just have the hose, would that be a bad thing? or is the filter a better way to go

[husqy360]

mine never got much oil in it, but yes they get very dirty preety fast, i clean it when i clean the air filter. i use the k&n kit. take 5 min max.

[aj_yz426]

I used the same type of black vinyl/rubber tube from home depot, a 1/2"x1/2" elbow joint and small zip ties for hose clamps (tube fit is so tight you probably don't need hose clamps. Maybe cost 6 bucks. I used an old piece of airfilter and a bottle from my kids bubbles (the ones you dip the stick into and blow. It was readily available and made out of the type 2 plastic resistant to oil/chemicals and the perfect size. Hopefully the pictures I added work.

Cut a small section of tube to just extend enough to fit over the connection on the valve cover and joint to the lower part of the elbow joint. If it extends too high will hit the bolt on the to engine mount. I'm pushing up on the loose gas tank so you can see in the picture, when its installed everything fits snug and the gas tank doesn't pinch off the tube (make sure of this if you do it). Once installed, you can't really see the tube.

Then I ran a straight section of tube back above carb, behind fuel petcock, just over throttle position sensor, under left frame spar and curve up through rubber flap into airbox. As a precaution, I also rerouted the 2 upper carb vent hoses into the airbox so if stalled in deep water my carb won't suck in water.

I didn't poke a hole in the flap, just shoved tubes through the cutout in the flap. Poking a hole would give better seal/fit, but would then destroy the flap if you messed up or wanted to put it back to stock. I will just have to watch for water leaking into the airbox and if it does, I plan to use some of that 3M sticky putty that you can stick posters to the wall(its yellow usually and reusable) and seal up any gaps.

The rectangular piece of air filter was cutout, then ziptied over the opening of the bottle. Then poke a hole in the middle and shove the breather tube through so it fits tight and seals. The tube extends about an inch down, allows for oil to collect at the bottom and the breather tube to take in filtered air, thus avoiding any sand or dirt from getting sucked into my engine at startup. If I ever see oil in the bottle, I can pull it off the end of the tube and dump the oil by carefully pulling the filter to the side or just cut the ziptie and remove filter, then re-ziptie it back. If you look at the picture carefully, notice the way the piece of filter is cut. It is actually a rectangle not a square, held down by the ziptie at the long ends, but not the sides. It seals tight over the opening but I can pull the part not under the ziptie to the side to dump oil out without removing the ziptie. That's the plan, haven't had to try it yet-no oil in there. I have an old oil filter and can probably make about 20 extra pieces to cover the opening if I need to replace in the future anyway.

Once finished, I blew through the end at the valve cover before connecting to make sure there is no resistance since it does take a bend and slight kink in the tube where it curves under the frame.

There was no resistance to air flow, so I hooked it up and has been working fine. This seemed to be the straightest simplest way to reroute the tube I could think of. My goal was not to put any major bends or kinks in the tube. If you had a custom molded tube to make the bend out of the valve cover it would be better, but I'm not sure where or how to do that, and the elbow joint works fine and doesn't restrict airflow even though it is smaller on the ID than the tubing, the elbow joint ID is about the same as the metal fitting coming off the valve cover so I assume it will not be a problem (and hasn't been yet and I've checked it by blowing air through with the tank in place, no resistance).

Seems like the black vinyl tubing is the same material as stock and hasn't melted from heat or oil exposure yet. Anybody see any catastrophic design flaws, let me know.

[02WR426Cali]

That's looks like a good design to me. I had my hose routed the same way a while back, as I didn't want to cut or drill into the airbox, but I didn't have a filter on it or the catch bottle so it made a mess in my airbox with the oil that comes out during a ride. A few rides and the box would get full of resin. So I routed it back to stock, but after seeing yours i might do that. Thanks

[psmith85]

aj yz426. What the 2 other small hoses that are in the aif box for?

[ThumperKid250F]

aj yz426. What the 2 other small hoses that are in the aif box for?

he said he was the carb vent lines..?

i like the bottle idea a lot beacuse it doesent get messy and you dont have to clean the little K&N style filter.

it looks like those are two awesome ways to rerout the lines..

thanks guys..

o BTW do you think i can use my stock hose?

[aj_yz426]

Those other 2 hoses are the upper carb breather hoses on either side. That way if the bottom is submerged in water or sand there is no chance the carb breather hoses will suck anything up:thumbsup: .

[aj_yz426]

I tried, but the bend on the stock hose didn't work for the way I routed it, it stuck out too far and looked bad. It looked like you would have to cut up the stock hose to use it. I decided to get the roll of black vinyl hose at home depot and keep the stock in case I ever wanted to change it back. The little plastic elbow joints are there for a buck or two. It was all in the same area of the store. I think the tubing is about 4 bucks for 10 feet.

[SparksXR426]

I have an 08 and since I was planning on using it as a track and trail machine this mod was on the to-do list. I didnt realize how important this really was until I pulled the valve cover off to check the valves today. 3 hrs on machine, 2 rides at the river and one short track ride. Valves of course are fine and there was an incredible amount of sand in the chamber around the breather! ? This mod is next and filters will be used.

[travisn]

Is my breather hose in the stock location? If so I can't believe it is just left there to make a mess of everything.

And do I have too many hoses (as can I reduce it down to 2, if not, why?), AJ only has two carb hoses going into the air box. From what I understand, there is a 'T' on each side of the carb so there is less chance of getting a plugged hose effect anything? Can one end be plugged if the other is going into the air box? And finally, why are AJ's carb hoses 'filtered'? Does gas come out of them, if so when and why? ?

yes yes yes, I know its a dirty filthy pig. I am going to do the best I can without taking the motor out for this summer, next winter it is getting a full over haul...

[hellboy]

I pulled my cover off the other day to check my valves and found dust on my head too,valves where ok.I only ride track,seems like a bad design to me:bonk:

[aj_yz426]

Is my breather hose in the stock location?

yes

AJ only has two carb hoses going into the air box. From what I understand, there is a 'T' on each side of the carb so there is less chance of getting a plugged hose effect anything?

the two hoses into the airbox are from the upper part of the T on each side of the carb, the lower hoses go to the bottom of the bike as usual. That way if I the lower hoses are submerged in water, crossing a creek etc., there's no chance water will get sucked up into the carb since the upper two hoses provide a the vent. If all four hoses were coming out below the bike under water, theoretically water could get sucked up. I've heard people say it happens, never seen it myself, but now I don't worry about it.

why are AJ's carb hoses 'filtered'?

I knew somebody would see that. As a precaution. I ziptied a piece of filter to the two hoses in the airbox to keep dirt and sand out. Similarly I ziptied a piece of filter foam over the two coming out the bottom of the bike (no picture of that right now). The airbox carb hoses are above the carb so typically would not get gas in them, it would drain down the lower two hoses. The foam on the lower two can get soaked with gas when the carb spills over, but its such a small amount and the filter material is pretty resistant to gas anyway. I'm not sure the foam on the lower hoses will last long trail riding, if it gets pulled off I will probably let it go.

If you were really environmentally friendly, you could install a catch tank for the carb and oil breather hoses like on supermoto bikes and not spill any gas or vented oil, but that's another story and way more expensive (I do have the catch tank for coolant behind my number plate made out of a rubbing alcohol bottle, can get a pic tomorrow if anyone wants):

I also left the 5th tube that drains the carb float bowl at the bottom of the bike without a filter since that is normally shut unless draining fuel from the float bowl, in which case I don't want a filter on it. So there are a total of 3 tubes sticking out under my bike (instead of 5).

[426 NOOB]

the two hoses into the airbox are from the upper part of the T on each side of the carb, the lower hoses go to the bottom of the bike as usual. That way if I the lower hoses are submerged in water, crossing a creek etc., there's no chance water will get sucked up into the carb since the upper two hoses provide a the vent. If all four hoses were coming out below the bike under water, theoretically water could get sucked up. I've heard people say it happens, never seen it myself, but now I don't worry about it.

I knew somebody would see that. As a precaution. I ziptied a piece of filter to the two hoses in the airbox to keep dirt and sand out. Similarly I ziptied a piece of filter foam over the two coming out the bottom of the bike (no picture of that right now). The airbox carb hoses are above the carb so typically would not get gas in them, it would drain down the lower two hoses. The foam on the lower two can get soaked with gas when the carb spills over, but its such a small amount and the filter material is pretty resistant to gas anyway. I'm not sure the foam on the lower hoses will last long trail riding, if it gets pulled off I will probably let it go.

If you were really environmentally friendly, you could install a catch tank for the carb and oil breather hoses like on supermoto bikes and not spill any gas or vented oil, but that's another story and way more expensive (I do have the catch tank for coolant behind my number plate made out of a rubbing alcohol bottle, can get a pic tomorrow if anyone wants):

I also left the 5th tube that drains the carb float bowl at the bottom of the bike without a filter since that is normally shut unless draining fuel from the float bowl, in which case I don't want a filter on it. So there are a total of 3 tubes sticking out under my bike (instead of 5).

yeah, put up a how to on the catch can with pics. I have seen them done with turkey basters but never an rubbing alcohol bottle.

[grayracer513]

I also left the 5th tube that drains the carb float bowl at the bottom of the bike without a filter since that is normally shut unless draining fuel from the float bowl, in which case I don't want a filter on it.

You're wrong about that. That tube leads to a standpipe that is open at the top at all times and is used as an over-level drain to prevent flooding. It's as open as the rest of them are.

[aj_yz426]

You're wrong about that. That tube leads to a standpipe that is open at the top at all times and is used as an over-level drain to prevent flooding. It's as open as the rest of them are.

Thanks, I'll include that one into the filter foam as well. Does the valve that opens with the allen bolt left side of carb bowl just let air in so the gas can drain out that tube? I thought it was to drain the float bowl instead of opening the big plug at the bottom. Now that I look at the diagram in the manual I see the standpipe part.

Sould I even worry about the carb hoses? Do you really think the carb can make enough negative pressure to suck anything up the vent hoses to begin with? I was more concerned with the oil breather hose since that could suck up 426cc's of water if trying to start the bike while the tube is submerged.

[travisn]

Yea I wondered why these bikes dont have over flow containers. Seems stupid, if the coolant expands when heated up and leaves the bike, how does it get sucked back in when it cools off. does a WR one bolt up?

And that catch can is really trick..