K&N oil filter part#
 

Maybe someone here can help me out, im looking to get some k&n oil filters for my 09 sportster, depending on what site im looking on, im comming up with 2 part#'s a KN-170C and a KN-171C, anyone know what the differance is? is the 171 just an updated part number?
thanks!

Kn-170c does not have a anti drain back valve, the kn-171c does i do not use the kn filters because i'am not sure of the micron rating,some where around 1999 they opened the scavenge side of the oil pump a little bigger so you can use a filter with a lower micron rating,my bike is a 1997 and it calls for a 30 micron filter.

The KN-170C is the correct micron size filter for the Sporty. The Sporty and all Harley EVO motor specs for that matter, do not call for an anti-drain back valve.

K&N's web site calls out the 170 and that is good enough for me. Just twisted one on yesterday prior to the first ride of the year. Man it was nice out in central PA.

The "C" just means chrome. Kn-170 is right though. I get the black "b" version. And the 170 is mentioned directly on K&N's site to use for Evo sportys

As for the 171. DK custom claims not to use it, something about the micron rating is too restrictive and to use it on twin cams only
https://www.hdforums.com/forum/sport...d-n-171-a.html

In J&P's description of the 170 an 170C it "long", as you can see, it just ain't so.