Welcome to Netrider ... Connecting Riders!

Interested in talking motorbikes with a terrific community of riders?
Signup (it's quick and free) to join the discussions and access the full suite of tools and information that Netrider has to offer.

Airbox to pod filter upgrade ... what about this hose??

Discussion in 'Technical and Troubleshooting Torque' started by drewzor, Feb 28, 2009.

  1. Hello everyone,
    I've bought a pod style filter to replace my airbox in my bike.
    However I have realized that there is hose that runs from my engine
    back into my airbox. It bypasses the filter and I believe it to be for blowby gases.

    My question is this;
    If i replace my airbox with this filter what should i do about this pipe?

    1) cap it off
    2) leave it disconnected
    3) modify a connection into the pod for it

    discovered it is a crank case breather hose..

  2. Definitely do not cap it off. Either vent it to atmosphere(buy a small breather filter to chuck on it), or modify your intake so that you can plumb it back it.
  3. Make your own catch-can as I did, very simple. Get a small plastic drinking bottle (300ml or so), wack some of the wire scouring pads inside, make a hole in the lid to put the tube in, and make some small breather holes in the lid or just beneath it.

    Rather than blocking it off it can now vent as it is supposed to and you will catch the crap in the bottle. Empy as necessary - won't be very often.
  4. drewzor, I'm interested as to why you replaced your airbox with a POD filter?
  5. I like to experiment, no grand design in the decision, more a learning curve. I'm just enjoying trying different things to learn how and see what effect it has.

    I have discovered these few things.

    It is a crankcase vent, it is attached to the airbox for emision control.
    Alternatively K&N and many airfilter manufactures make crankcase vent filters.

    By using a pod filter you bypass the heated gases that come from the crankcase vent.
  6. I fail to see why you'd bother making an illegal modification to gain more power when you could have just bought a 250.
    Especially when the potential fine is worth more than your bike is.
  7. I'm not looking for more power, as I have already explained I'm trying my hand at some basic mechanical experiments.

    I didn't know it was illegal but that is exactly why I posted here, to get informed of these things or be corrected on my conclusions.

    edit additional;
    I have done a basic search on the legalities of this after your post JD but I fail to see anything to suggest it would be illegal besides noise control?
    or am I missing something, can you help explain the legal implications of this modification.. and is the fine really over $4000? thats heavy handed imo

    Thanks in advance!
  8. And you haven't done any illiegal mods to your bike either like exhaust or braided brake lines? :roll: Any mod to the bike is illiegal unless it is ADR'd or certified by an engineer.
  9. I remember seeing a post on here some time back that suggested
    that ADR's were not enforceable. That is, you could not be pulled over
    because of noncompliance, however, you could be fined for defect if after
    you have been pulled over (for example speeding) the officer finds you bike to be too loud, dangours or distracting (neon lights etc)
    even then doesn't it have to be tested to prove its defectiveness?

    How would a pod filter and crankcase filter become reason to be pulled over and charged excess of $4k..

    Makes me wonder how K&N are still in business?
  10. drewzor, generally speaking you will only get pinged for mods if you are being a tool - either on a bike or a car. I've driven a 500+hp Commodore for the last 6 years with no problems - plenty of engine mods etc, been through breathos etc etc with no dramas.

    Yet you be a silly boy and get pulled over for it and most likely they will also look at what else they can get you for.

    Don't worry about it!!! I did the same as you, removed my airbox and put on dual K&N's, exhaust and re-jetted my carbs. I'm a member of car forums too and there's always talk of EPA and big fines etc etc from people who don't want to modify their ride, but does anyone ever know of anyone being fined like that? Nope.
  11. That is what I was thinking, I ride safely and don't do anything to attract unwanted attention.

    Could I ask you, what did you do for your crankcase breather hose?
  12. See post 3 in this thread, I "built" a simple catch-can.

    Took me 10 mins to do this and if it's sealed (not venting to atmosphere) there should be no legal issues either as it's venting to atmosphere that is the issue in this case.
  13. Nope. Exhaust is legal (already passed 2 RWCs), and the braided lines are ADR approved. So
    (And not all mods. require ADR or engineer approval - only those relating to items covered by an ADR).

    Drewzor, the relevant laws are:
    For altering the pod filter - oiled filters aren't allowed to be exposed to air since this is considered to increase emissions.
    For altering the emssions control - ie the breather hose

    1 Penalty Unit = $113, so you're looking at 4.5k if you get pinged for both. Keep in mind too that you may also have issues with insurance if the mods. aren't declared (depends on the policy but undeclared illegal modifications do give them a pretty valid "out" in the event you need to claim money from them). No idea if insurers would still cover the bike with the mods., or if it would effect your premium (plenty of insurance experts on here that I'm sure could answer that though).

    K&N are still in business because:
    a) Some people don't care what the laws are, and in some parts of the world things are less restricted.
    b) Using a K&N filter inside a factory airbox is virtually undectable and, depending on who you listen to, also completely legal.

    Edit: Oh and FWIW I do know a couple of people that have been booked for having a pod filter fitted to their car as a result of a random vehicle inspection - and the fines were substantial (they never told me how much but given one ended up selling their car I know it wasn't a minor amount).
  14. Nope, you're wrong. Passing an RWC does *not* make it legal. You can still get done for it regardless of what you think.

    Braided brake lines for example (as you have fitted) are not legal unless they have been ADR tested on the specific bike and they supply you with the relevant paperwork - which I bet they haven't.

    Another case of my mates brothers uncles friend got a fine :roll: and I'm sure it was $4000 :LOL:

    edit: I don't think quoting Vic laws has much benefit seeing as Drewzor is in NSW.
  15. No, for a 1985 bike the exhaust is totally legal under Vic. legislation (it predates the stricter emissions regulations introduced in 1986). And my brake lines WERE provided with full ADR compliance - it's the reason why I bought HEL's. Hmm, I think I need a bigger bunny.

    And yes you're right NSW is different to Victoria - they're actually a lot more strict (hence the legislation a few years ago making any exhaust without the appropriate sticker illegal). It seems the maximum penalty for tampering with emissions control equipment in NSW is actually $250,000 :shock: .
    Relevent legislation.

    Just because YOU may not know anyone that's been booked for illegal modifications doesn't mean it doesn't happen :roll:.
  16. Don’t be surprised if the bike actually puts out less power than it currently does. Air boxes on bikes (particularly high revving ones) are designed for more than holding the air filter in place.
    Pressure waves are traced and the fuelling system is designed around them. Hot crankcase gasses will do SFA.
    By all means do the experiment but don’t mistake induction noise for anything more than that.
  17. I'm having trouble finding information on pressure waves.
    could you please give a brief explanation or post a link?
  18. Some info here Google but plenty more if you are willing to search.
  19. Thanks for that, so i found this simple explination;

    "When the intake valve opens, air is drawn into the cylinder by its downward movement. When the intake valve closes, the air in the intake is still moving forward towards the valves. It runs up against the closed valve and creates an area of high pressure. This high pressure is then redirected as a wave back up the intake tract away from the engine. When the pressure wave reaches the open end of the intake tract, it reflect back down the tract towards the engine. Now if this wave approaches the valves as they are open, it will help flow more air into the cylinder. The valve closes and the process repeats. This process results in increased volumetric efficiency (more air passing through the engine)...and therefore, more power."

    So How can I calculate this into the design? My first impressions are that I have to work out a basic distance from the intake to the airfilter based on stroke maybe?
  20. Start by reading this.
    Once that makes sense, then you might have a chance of designing something more effective than what the engineers at Honda came up with.

    Edit: Oh and you might also want to add this and this to the reading list