Re-routing Air Box Breather Tube help


19 replies to this topic
  • MountainMax

Posted November 25, 2006 - 02:05 PM

#1

I read the following in another thread, didn't want to hijack it, what can you guys tell me about this,>>

REALLY consider rerouting the engine breather hose up to the now unused AIS fitting on the airbox (water in the air box will go into the top of the motor as currently configured)


Is this something we should all be doing after removing the AIS ??

  • simon@vic

Posted November 25, 2006 - 05:42 PM

#2

something every one whit any year wr should do.

currently if you stall in a river. it can suck water in on your restart!

  • farkawi

Posted November 25, 2006 - 05:49 PM

#3

Mine is an '05 and I just added hose to the stock location and routed the additional hose to the top of the airbox in hopes that I never get in water up to the seat! I also routed the carb vent tubes up along the top of the airbox along the frame rails.

  • tony1970

Posted November 25, 2006 - 07:02 PM

#4

I thought of running the breather to the old AIS top fitting but thought twice when you consider the engine will be spewing oil fumes through the carb.:worthy:

  • waynus

Posted November 25, 2006 - 08:16 PM

#5

something every one whit any year wr should do.

currently if you stall in a river. it can suck water in on your restart!


Wouldn't it be more likely to suck it in the carby? Bout time someone did some tests with clear tubing to see what really happens...starting, idling, under load and decelerating. I'll try and work out how to do it but it would be good if someone beat me to it, maybe something like a bong where the water wouldn't get sucked in.:worthy:

  • Just_a_trail_rider

Posted November 26, 2006 - 07:28 AM

#6

I've heard about this before. I have an 05 wr450. My air breather hose goes to the bottom of the air box. Should it be on a fitting on the top?

Is there a pic somewhere?

  • BlueBlood Rider

Posted November 26, 2006 - 10:44 AM

#7

Wouldn't it be more likely to suck it in the carby? Bout time someone did some tests with clear tubing to see what really happens...starting, idling, under load and decelerating. I'll try and work out how to do it but it would be good if someone beat me to it, maybe something like a bong where the water wouldn't get sucked in.:worthy:

The hoses coming out of the carb and routed down in front of the swingarm are nothing more than atmospheric vent lines. There is no positive vacuum ever present sufficient enough to draw water or dirt up into these hoses. The crankcase vent hose is entirely different. It is constantly changing from negative to positive vacuum and can actually suck water and/or dirt into itself. While the engine is running, these negative/positive pulses are so short that the risk is minimal, if not impossible. But when starting, the positive vacuum duration is indeed long enough to be able to suck water the entire length of the hose and into the engine, particularly if the hose end is submerged and the bike doesn't start immediately. If it is a concern for you, rerouting the vent hose into the airbox is the best way to eliminate the risk. I recommend placing the hose above the filter in the airbox, not below. There'a a reason the WR airbox has a drain fitting at its lowest point. Is that really where you want to put the vent hose? I don't think so. The miniscule amount of oil-laden vapor mist coming from the vent hose will fall harmlessly onto the filter element and water/debris that collects at the bottom of the airbox will not be sucked into the engine.:D

  • BlueBlood Rider

Posted November 26, 2006 - 10:50 AM

#8

I've heard about this before. I have an 05 wr450. My air breather hose goes to the bottom of the air box. Should it be on a fitting on the top?

Is there a pic somewhere?

Here's a link to an article on WR mods. Click on the Dirt Rider pages at the top.
3w mcjournalist dot com /articles dot html (why can't we post web links in here?)

Thumperfaq dot com is also a good resource.:worthy:

  • waynus

Posted November 26, 2006 - 12:05 PM

#9

The hoses coming out of the carb and routed down in front of the swingarm are nothing more than atmospheric vent lines. There is no positive vacuum ever present sufficient enough to draw water or dirt up into these hoses. The crankcase vent hose is entirely different. It is constantly changing from negative to positive vacuum and can actually suck water and/or dirt into itself. While the engine is running, these negative/positive pulses are so short that the risk is minimal, if not impossible. But when starting, the positive vacuum duration is indeed long enough to be able to suck water the entire length of the hose and into the engine, particularly if the hose end is submerged and the bike doesn't start immediately. If it is a concern for you, rerouting the vent hose into the airbox is the best way to eliminate the risk. I recommend placing the hose above the filter in the airbox, not below. There'a a reason the WR airbox has a drain fitting at its lowest point. Is that really where you want to put the vent hose? I don't think so. The miniscule amount of oil-laden vapor mist coming from the vent hose will fall harmlessly onto the filter element and water/debris that collects at the bottom of the airbox will not be sucked into the engine.:D



Two things Blue Blood,
I meant that if there was water in the filter box, it would get sucked through the carby into the motor in which case the breather would be the least of the worries.

Secondly, maybe the end of the engine breather pipe needs to be lower than the top of the motor to drain condensation and condensed oil vapours.

I'm hearing ya re positive and negative pulses. I'm devising a bottle filled with water and two pipes coming out (like a bong, if you know what that is) to see if the water bubbles.


:worthy:

  • MountainMax

Posted November 26, 2006 - 02:14 PM

#10

Thanks for all the feedbacks guys, I think I will leave well enough alone........

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  • black_n_blue_thumper

Posted November 26, 2006 - 02:46 PM

#11

Thanks for all the feedbacks guys, I think I will leave well enough alone........



Hey bud if its still stock, it may not be well enough. Its your ride, do what you want. But I saw this happen to my bro. Its easy to just route the tube into the air box. I just drilled a hole slightly smaller than the breather tube, then pulled it through with some needle nose pliers. It was tight enough that it never came out. Worked great for the 2 years I had my WR. I did the same thing with my YZ, its just not worth the risk to me. :worthy:

  • BlueBlood Rider

Posted November 26, 2006 - 07:54 PM

#12

Two things Blue Blood,
I meant that if there was water in the filter box, it would get sucked through the carby into the motor in which case the breather would be the least of the worries.

Yeah, that's for sure!:prof:

Secondly, maybe the end of the engine breather pipe needs to be lower than the top of the motor to drain condensation and condensed oil vapours.

Not really. I have 2 Yamahas (a YZ250F and WR450F) that I have done this to and have been running for more than 2 years this way. There is so little oil vapor that comes out of there that it isn't a real concern. If you tip the bike over upside down for more than a half minute, oil from the crankcase could enter the hose and flood the airbox, but that's a long shot, too.

I'm hearing ya re positive and negative pulses. I'm devising a bottle filled with water and two pipes coming out (like a bong, if you know what that is) to see if the water bubbles.:worthy:

Drag and road racers have been using similar catch tanks for years. Some sanctioning bodies require them to keep oil off the track surface. AMA Supermoto racing requires them for the same reason.:D

  • BlueBlood Rider

Posted November 26, 2006 - 07:57 PM

#13

Thanks for all the feedbacks guys, I think I will leave well enough alone........

If you ride in wet or dusty conditions or do any kind of water crossings, protect yourself and do something with the hose. Even if it's as simple as a little plug-on filter on the end of it (K&N makes them) you'll be better safe than sorry.:worthy:

  • steel-eye

Posted November 26, 2006 - 10:07 PM

#14

I was going to put a T junction at the top of the origional breater and run a new hose from that to the air box. Still letting any oil that may occure out the bottom hose not to the air box, and if the bottom hose is in water the top hose will still let it suck as air is lighter than water so yo dont get water in your eng. I tried it with some pvc garden hose and worked a treat.
Just wonderin if there would be any problem with doing this
Thanx

  • waynus

Posted November 26, 2006 - 11:39 PM

#15

I was going to put a T junction at the top of the origional breater and run a new hose from that to the air box. Still letting any oil that may occure out the bottom hose not to the air box, and if the bottom hose is in water the top hose will still let it suck as air is lighter than water so yo dont get water in your eng. I tried it with some pvc garden hose and worked a treat.
Just wonderin if there would be any problem with doing this
Thanx


Sounds like a good idea except that that same hose going to nowhere can suck up dust ( if there are truly positive and negative pressures). I reckon inside the airbox is a negative pressure so anything comiing out of the breather is sucked into the airbox(meaning dust wont find it's way into the tappet cover). However if you're going to run a hosw outside the airbox as well, I would recommend some sort of filter on the end, even if it was a piece of oiled foam rubberzip tied around the end of the hose.:worthy:

  • boer

Posted November 26, 2006 - 11:50 PM

#16

I was told a while back in a post not to worry and instead to worry about checking if my tire valve caps are on tight enough:lol: :worthy:

Here is the link

http://www.thumperta...ad.php?t=430187

  • waynus

Posted November 27, 2006 - 01:34 AM

#17

I was told a while back in a post not to worry and instead to worry about checking if my tire valve caps are on tight enough:lol: :D

Here is the link

http://www.thumperta...ad.php?t=430187



I remember that now. I must admit that I also wondered what valve caps he was talking about, thinking back to the bikes of old when they had screwable caps to adjust the valves. He gotcha (and me)

It's good to get opinions but without proper testing, they are only opinions. Best to keep digging IMO til you're satisfied. For me, it's a $10,000 plus purchase and I want to get maximum return for my money. If Yamaha put the breather there cos it was the "most convenient place", then it's up to us to find the most beneficial place.:worthy:

  • boer

Posted November 27, 2006 - 06:21 AM

#18

I remember that now. I must admit that I also wondered what valve caps he was talking about, thinking back to the bikes of old when they had screwable caps to adjust the valves. He gotcha (and me)

It's good to get opinions but without proper testing, they are only opinions. Best to keep digging IMO til you're satisfied. For me, it's a $10,000 plus purchase and I want to get maximum return for my money. If Yamaha put the breather there cos it was the "most convenient place", then it's up to us to find the most beneficial place.:worthy:


Yup, I think this topic is long from being exhausted. Time will tell.:prof: The more people tinker around the better for us all.:D

  • lowry

Posted November 27, 2006 - 01:02 PM

#19

This just got me rethinking what I’ve done with mine. I originally hooked up the breather hose to that one nozzle looking thing sticking out the bottom of the air box on my 426, there was no plastic/rubber cap thing on it when I bought it and I didn't know what it was for, I just stuck the breather hose on cause it fit so good like it was supposed to be there. I had no problems, only a little oil in the bottom of the box that I cleaned with the filter change. Someone in another thread mentioned that this nozzle thing was to let water out so I removed my hose and zip tied it right there to the frame so it was at least higher that it was originally, plus it helped oil the chain. Now I’m thinking that if you have to worry about so much water in your air box that it needs to drain don't you have bigger problems, like water getting into your carb? If I go through water so deep it drains into the top of my air box I would imagine it would go right into the carb before it all drained out that nozzle. What do you think?

  • TD-3

Posted November 27, 2006 - 02:58 PM

#20

I bet this guy wishes he had re-routed the vent hose :worthy:

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