Has anyone opted for the K&N air filter instead of an after market AC? If so, did you notice a significant change in the bike? HD and K&N both recommend a tune when using the K&N filter in conjuction with slip ons (poor man's stage 1). Anyone not get a tune with these upgrades? Let us know!

 

while there's more to a high flow AC than just the filter element..this one has twice the surface area and is more porous than OEM, if you add less restrictive mufflers as well, you'd be well advised to listen to K&N & HD and get the tune adjusted appropriately..IMO..don't take the chances of harming the engine and voiding your warranty

 

I do not disagree. My bike came with rinehart slip ons from the dealer. So, if im gonna pay for a tune because of a $45 air filter, I might as well upgrade to an after market AC? I'm sure the tune isn't cheap.

 

I think you'd be better off with either an aftermarket or SE AC if you're doing a complete Stage 1...but the K&N and OEM AC might very well provide enough air, while providing better weather protection tho so you could try it first, only out $60 if you decide to upgrade later

 

The K&N guy at Sturgis told me that with only slip on and their filter, nothing else needed, no tune etc.

 

Not sure if he's right though myself , it will run lean .

 

Just fitted the H D breather kit with backplate upgrade.This is not like the Twincam upgrade I have made many times!
The filter is seriously double the size and more porous so it makes an immediate and drastic improvement in response and performance.The exhaust note increases and the crackling and popping tells me it is running leaner!I would say that a fueling tune is mandatory
This kit no longer accommodates the lower plastic cover or front Ram screen which is an admirable and attractive piece of design engineering.Glad to say I managed to honor the Designer and made modifications which allowed it to be refitted,now it looks great and kicks ****!Bit of a Sleeper��

 

The bike has sensors, and the ecm adjusts. The filter isn't that big of a change

 

It will run leaner, with the EPA's today they're already on the lean side, with a slip on and a free flow air filter it'll run leaner still.
As far as I've read everyone who has gone to aftermarket cans and a free flowing air filter has had to tune their M8 to run well.
It'll still run but it'd be on the lean side of things..

 

wasn't they guy I talked to at K&N after they introduced the 1717, who told me the opposite..I called them after posing the question to our HD service tech who advised me to ask K&N about the flow rate compared to OEM..better to be safe than sorry on a new bike imo