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:
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.
Is it possible to install the unit backwards?
Where do I mount the KVP?
What if my bike breathes through the heads, do I need 2 units?
What if my bike breathes both top and bottom? Can I still use the KVP?
Does it matter if there's a filter on the end?
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.
Can I get replacement parts?
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.