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Valve cover air-return hose after pods installed?????

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  • Valve cover air-return hose after pods installed?????

    93 Kat 600

    I'm wondering what I should do with the hose that normally runs from the top of the valve cover to the stock airbox. -- I installed new carbs with K&N Pod filters and I no longer have the stock airbox, and therefor nowhere to run this hose to; currently it's just sitting there, and I tapped a peice of fabric over the end (a cheap filter) incase it act's as an air intake into the engine.

    What is the significance of the hose, and is it necessary for proper running performance? Just wondering what I should do with that I don't seem to have a need/place for it. Can I just plug it?


  • #2
    do not plug it its the pcv hose they do make a lil fiter to go on the end of the hose


    • #3
      From KR: Mechanics 101: Breather Filters when and why should they be used.:

      Originally posted by The CyberPoet
      It goes like this:

      Every time your cylinder detonates, some of the fuel gets pushed against the walls (just a little tiny bit in most cases). As the piston sweeps up and down, it carries away that tiny bit and it falls with the oil down into the oil pan with the oil that carried it away.
      Once there, it heats up and turns back into a vapor again, which then rises to the top of the engine normally. To keep these vapors from building up to explosive quantities in the oil passages, the stock engine draws the vapors off the top of the valve covers back into the air box (through the vent tube between the valve covers and the airbox), to get recycled (burned off) by mixing with the inbound air going through the carbs. If too much fuel is ending up in the oil (such as a stuck carb float causing fuel to run into a cylinder when the bike is parked), the vapors will reliquify in the airbox (due to condensation from being cooled by the in-rushing air) instead of being drawn back into the carbs, and you end up with an airbox full of oily-fuel... One of the reasons the airbox has a drain tube (to let you drain out any build-up).

      Under certain set-ups that eliminate the airbox (the pod-filter set-up), there is no provision to route the vent gases back into the intake for the bike; in those situations, you place a breather filter on that opening on the valve covers to keep debris from falling in, and hope that it will vent sufficient vapors that spontaneous combustion in the oil galley won't occur.
      =-= The CyberPoet
      Remember The CyberPoet


      • #4