REF: Engine Mechanicals - Sub-04B


Frequently Asked Questions About the Hayden Krankvent

This is what is published by Hayden regarding the Krank Vent.
Krank Vent Plus, Crankcase Venting System For ALL Harleys.
Sugg. Retail - $124

More than simply venting your crankcase fumes,
The Krank Vent Plus controls the air under the pistons by maintaining the proper amount of vacuum in the crankcase at any RPM.
You'll gain 2-8% of useable rear wheel horsepower. Your engine gains a quicker throttle response.
The unit snaps open for easy cleaning, is not restricted to position and is compact and light weight to fit all Harley Davidsons.
(including the hard to fit 93 and up head-breathers)

These FAQ have been copied from the Hayden Enterprise site:

  1. How do I clean the KVP?
    • Remove it from the hose clamps, snap it open then wash it in hot, sudsy water, rinse and let it air dry.
      Then reinstall. DO NOT use compressed air to dry it. Also stay away from harsh solvent when cleaning.
  2. Is it possible to install the unit backwards?
    • Yes, but be careful not to. The KVP is marked on one end with a grooved ring.
      That is the EXIT end of the unit that will lead to an air filter.
  3. Where do I mount the KVP?
    • The KVP is not restricted to position. It can mount vertical or horizontal. Pick a place to mount it then run the line to the unit.
      Watch for sharp bends or crimps in the line. You do not want to restrict air flow.
  4. What if my bike breathes through the heads, do I need 2 units?
    • No. Simply install an after-market head breather adapter kit. This will connect each line to a 'T' or crossover bar.
      Drop a single line from the bottom of the T that will connect to the KVP.
      Place a short hose on the 'EXIT' end of the KVP and run that to your filter.
  5. What if my bike breathes both top and bottom? Can I still use the KVP?
    • We suggest you plug one end and breathe through the other. You can plug the top end by replacing the hallow bango bolts with solid bolts.
      Then install the KPV on the remaining line coming directly out of the crankcase.
  6. Does it matter if there's a filter on the end?
    • Although the KVP puts you in a negative air flow (3-5 pound vacuum), it does suck in a small amount of air and that air needs to be clean.
      We suggest a filter 3-6 inches after the KVP.
  7. What is the 'milk shake' looking liquid that collects in the KVP?
    • That is merely condensation with a bit of oil in it. It will not hurt the unit. Most bikes don't see this.
      If the KVP is closer to the heads, it may collect some condensation. Simply snap open the KVP and wash it with hot sudsy water, rinse and reinstall.
  8. Can I get replacement parts?
    • Yes, you can always get pieces to any of our products directly from us.
      The only thing you may possibly need on a KVP would be an umbrella valve and that would be only if it became contaminated with gasoline.
      (gasoline will cause the rubber to swell and distort)
  9. Is the KVP restricted to a specific bike?
    • No. We can install on any bike that has crankcase pressure.
      (ex: Sportsters, Big Twins, Baggers, Customs, Fuel Injected, etc.)
      Just be sure to address ALL the breathing areas. We want to be sure we're capturing all the air pressure.


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