Alright I've searched and read as much as I care to on the interwebs, now I'd like to hear from some real people with real stories/experiences.

The bike is a 2014 Road King, I'm running freedom performance fishtail slip ons, I have a Vance and Hines fuelak 3 for tuning.

I'm looking for a good air breather to complete the stage 1. I like the "look" of things like the Arlen ness twin sucker or the various "spiked" breathers but I don't know if any of those are the right one for my particular bike (other than look). And I'm concerned about water (rain) infiltration. I know you can get a sock fir them, but that seems to defeat the purpose of the upgraded filter.

What say you?

 

the stock Rushmore air cleaner you have will flow as much air as the motor could ever demand- it'll flow about 175 CFM.

so any other choice is pretty much fashion

there are advantages ( some of us believe) in using an oiled filtermedia which is washable and reusable- filtering is thought to be better and the K&N that I put on my fxr in 1990 has paid for itself.
so for some just a filter will do it.

most aftermarket air cleaners flow much more than stock- for instance the Ness big sucker and the S/E high flow both come in at about 260 CFM.
There are a few which do not flow much more than stock and are a chromey gee gaw ( hype charger- 150 CFM)

a snorkel type air cleaner may give better torque numbers ( due to it's length) depending on the cams- but for a street bike this is almost unmeasureable...but in theory...

some guys find a fit problem with lowers, brake pedal ( me) or pushing the knee out.


the stock air cleaner is made to muffle noise..it is amazing how many riders post on the forums complaining about intake noise when they have removed the noise muffling device
...that's right up there with installing black out lenses on the lights and complaining that they can;t be seen

https://www.hdforums.com/forum/touri...s-open-ac.html


Mike

 

Good piece of info about the stock air breather. So now I'm a little confused by the need to replace the stock breather to "achieve" stage 1 upgrade if that is the case. I was under the impression, the more air the better and use the tuner to balance it all out, no?

 

in simple terms, yes. but, there is a point of maximum air intake. the motor will not take in any more air than in can possibly use. and like mkguitar says, the stock ac will flow more than your motor can use. and even though some of the aftermarket filters will flow more than others, it is a moot point if your motor can't use it. if the motor needs 125 cfm and your air filter could flow 500 cfm, it will not outperform another filter than only flows 175 cfm.

so, go for the look you like, whether it be the round k&n, or the heavy breather or big sucker, it's all on you. or if you like the 'stock' look, just upgrade the filter and call it a day.

 

I think the limiting factor is not your air cleaner, but the cat in your head pipe. Flowing more in will not help much, until you de-cat the header or get a new one without one. Most aftermarket air cleaners will flow more, even than the Rushmore cover. The stock filter is too small. Rushmore is better, and more than good enough with a cat in the headpipe.

For me, when the time comes, I'm going to get the DK Customs stealth AC. Lets you keep your stock cover I really like the look of my Rushmore cover, esp because it says "103 Police" just want to keep it.

Laslty, if you do get a new AC, read up about external breathers. I'm a beleiver. Why pump blow-by directly into the intake? (Except that's what the EPA wants). Even with the stock AC, I did a DIY external breather mod.

 

it's the displacement x rpm...

physics does tell us that under certain conditions the cylinder can accept a more than 100% cylinder fill ( look up scavenging and cam overlap) and under many conditions a less than 100% fill.

don;t worry much about recirculating oil fumes into the intake- oil has been recirculated to the intake on every car since 1963.


Mike

 

Roger that. What about water infiltration? While I like the look of the protruding spiked air breather, I certainly don't want to cause a problem by using one.

Thanks for the replies fellas. Appreciate the explanation of the CFM and max usage.

 

I switched mine out for an S&S Stealth and used their Airstream cover. I like the looks of it and find it a bit slimmer than the factory. As said above, the factory will flow enough air, I just did mine for a looks thing.

 

Keep what came with the bike.
I looked at a dyno chart showing slight improvement using an aftermarket cleaner, (in my case a Kurykrapin Stealth III), and bought into the hype. Of course couldn't feel any difference in power.
But now I'm happy to relate ...NOT!, that my $30k bike has oil all over the side of the motor thanks to not properly being reburnt like the original one did so effectively. $204 wasted.

 

Direct Cycle Parts, V&H Vo2 Stage 1 breather, Why?: It allows external crankcase breather hose install. Also checkout DK Customs for their breathers. I Bought the Vo2 for the quality and the price thru Direct Cycle. The ANess chrome breather is well made, but routes hot/dirty crankcase vapor into throttle body and it will drip out of A/F after hard riding. You can use the stock chrome Harley cover or any chrome cover that wraps around the filter. I am not a fan of the open or spike set ups that require a sock.