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Discussion Starter · #1 ·
O.K, so I would like to run a K&N filter. However, I notice how the crankcase vent pushes into the stock foam filter.

How am I going to accomplish this on a K&N.???

Does anyone have a fix for this? I want to run with the airbox lid off, so I cant just leave the hose unfiltered can I???
 

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K&N sells a crank case filter as well and comes with the filter and clamp for about $15. Your dealer should have it in stock.
 

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yea there is a post either here or on exriders that has a pic of the setup with the k&n crankcase breather
 

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Discussion Starter · #4 ·
Originally posted by quadboy@Sep 14 2004, 10:46 PM
K&N sells a crank case filter as well and comes with the filter and clamp for about $15. Your dealer should have it in stock.
Will this stay inside the airbox, or does it get moved outside?
 

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it stays in the box
 

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Discussion Starter · #6 ·
Originally posted by t00muchmetal@Sep 14 2004, 10:51 PM
it stays in the box
Thanks a bunch metal. I'll give the dealer a call.
 

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no problem

I couldnt find the post but

the guy that did the mod connect a hose to where the crankcase tube came in the airbox and then ran it along the side of the airbox to the back and had it mounted there

im sure tomarow someone will be able to find the post

dont know if you can make sense of my description but i tried :D
 

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i spoke with someone at Baldwin Motorsports today but didn't get his name. among some of the info i was trying to get from him was what they do with the breather hose when they build a 450r motor. he first told me that he could sell me thier mod. when i asked how much, i guess he began to feel guilty and said that they just pull the stock hose out of the airbox then replace the stock hose with one that will bend nicely without kinking and route it down between the swingarm and motor just like the carb bowl drain hose. i asked him if i could just run a hose from the valve cover and a seperate hose from the crank case. he told me "no" and that i need to keep the "T" joint in place because it is a "vital" part of the crank vent system. i didn't want to take more of his time by asking why. he also said that there was NO need to place any kind of filter on the end of the vent hose as long as the hole is facing down and to make sure that the hose is routed AWAY from the exhaust.

i know that several people are going to disagree with this suggestion. however, i have been wondering why we need to filter this hose when in the past i have never seen a filter on a crank vent hose on a dirt bike. i am going to try and get more info from Sparks and Duncan this week on the topic. in the mean time, if anyone else can shed light on the subject... please educate me.


thanks
 

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it can never hurt to run a filter on the end of a crankcase breather hose, it's only cheap insurance. what if you do an accidental submarine in an unexpectedly deep water crossing? no need to let everything in.

it does however always hurt your machine to run a k&n. ever look through one at a light source? you might as well just leave it off alltogether and let your carb venturi stop the rocks from getting through.

the best test you can do is find a machine that has run one for some time and take the filter off so you can wipe a slightly oiled white paper towel inside the air boot.

i know some of you have them already, be brave and do this. then report without FILTERING the results
...............mixxer (an ex- k&n user \ i
my motors too much)
 

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Originally posted by mixxer@Sep 21 2004, 08:10 PM
it can never hurt to run a filter on the end of a crankcase breather hose, it's only cheap insurance.  what if you do an accidental submarine in an unexpectedly deep water crossing?  no need to let everything in.

  it does however always hurt your machine to run a k&n.  ever look through one at a light source?  you might as well just leave it off alltogether and let your carb venturi stop the rocks from getting through.

  the best test you can do is find a machine that has run one for some time and take the filter off so you can wipe a slightly oiled white paper towel inside the air boot.

i know some of you have them already, be brave and do this. then report without FILTERING the  results
  ...............mixxer  (an ex- k&n user \ i 
my motors too much)
I feel the same way mixxer ... about the filter on the breather hose AND about the K&N. If it lets anything by (it will) then you will end spending more $$ rebuilding your engine! The extra 0.5 hp (if that!) is just not worth it!!
 

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thanks for the reply mixxer. you have addressed two issues here...

using a k&n filter and filtering the breather hose. i forgot that this post started out as a k&n based question. since i don't use a k&n filter any longer either, i have no worries about dust. but, i was just thinking about taking the crank case vent air out of the combustion chamber. there is probably not much to be gained as far as hp goes. i was only looking at options. i was looking at a picture of tim farr's bike in a magazine and it appeared as if his crank breather was hanging under the bike. that's what sparked my curiosity. i thought that if engine builders were doing this mod, there could be a good reason.
is it likely that dust, dirt or water will travel up 10-12 inches of hose and find it's way into the crank case if only the end of the hose gets submerged? i do sincerely wonder. this question is not meant to be argumentative in any way and i am not going to keep asking until i get the answer i want. B) so... if anyone could spare a few more minutes of their time to add to mixxer's comments, i would appreciate it.

also, i would like to add that i did find some film in my intake boot after three rides with a k&n filter. that's why it is now in a land fill. other rider's results may vary.
 

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the reason honda put the hose to the airbox is mostly for emission\pollution reg compliance. the theory being that any unburned hydrocarbons blown past the rings would get a second chance to be burned if drawn in through the air filter a second time. if you get a lot of blowby this could seriously pollute your incomming charge of "fresh" air. it could also make the intake charge less dense via the added heat........................hmmmmmmm i think i will stare at mine again tomorrow


great observation reddogg...............mixxer
 

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i am still undecided on exactly what to do with mine as well. i did notice the parts micro for the 450r refers to the clip that holds the breather hose to the valve cover as an oil drain hose clip. i know there is a baffle in the valve cover that collects oil and it gets into the breather hose. i guess that is why the "T" joint is so vital... it allows the residual oil in the hose to drip back into the crank while allowing the case to breath at the same time. if you elliminate the "T", you will probably drip/lose a little oil here and there. not much though.

i also observed that the transmission side has a seperate breather hose that is not filtered. it runs up to the heat shield under the gas tank and is tucked into a small hole. there is also a "drain hose" toward the front of the transmission side on the bottom of the case. it also is not filtered. i have not figured out what it drains yet, but maybe it is an overflow for trany oil or if water finds it's way in.


as you can see... i have nothing better to do tonight. ^_^ maybe this info will become helpfull later.
 

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Originally posted by wppracing@Sep 21 2004, 09:21 PM
With a K&N Air Filter you should be using a pre filter or Outerwears lid cover.
if this is done you reduce the advantage the k&n has (high surface area via the pleats) to nothing. doesn't a filter needing another filter to become effective sound a little funny???????? :lol: .........mixxer
 

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Originally posted by wppracing@Sep 21 2004, 09:21 PM
With a K&N Air Filter you should be using a pre filter or Outerwears lid cover.
i was using a Pro Design pre filter on my k&n. in any case... i feel more secure with the foam filters and i think that cleaning is easier. the trails are very dusty down here and it is easy to see when the foam needs cleaning. just a matter of personal preference for me. ^_^
 

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With a K&N Air Filter you should be using a pre filter or Outerwears lid cover.
if this is done you reducce the advantage the k&n has (high surface area via the pleats) to nothing. doesn't a filter needing another filter to become effective sound a little funny???????? :lol: .........mixxer
:lol: that does sound a little funny.....I will always use foam

Reddog...I agree 100%
 

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desert, don't let it get you down dude. sometimes it gets to be a one way street.

i would like information given in return for info given out (info is my favorite gift to receive) but not only do many not return the favor, many don't even say thanks.

others only come back with: i know a guy who knows a girl who has an uncle twice removed that says you aint sheeeeet. sometimes it gets a little old but that's just the way it is.

i'm still anxious but i have nothing more to say.........................mixxer
 

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dezert, if you can find a copy of the long out of print: the 2-stroke tuners handbook by gordon jennings, read his intro and you will feel better.

next, sucker punch the owner and run like hell. i would give $100 for a copy of that thing. i got to borrow one years ago but i still remember the intro.

.......................mixxer
 

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Desert,
when Vicious Cycle actually takes off, I'll give you $110 for that book....mixxer
 
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