Newer/Longer aftermarket filter
Seasoned HDF Member
Joined: Sep 2008
Posts: 13,905
Likes: 10,886
From: San Diego, CA
I think the HF171RC are the same as the K+N 171/171C.
The new harley filter from what I can find. 5 micron, 3.5 to 4" (102mm) in length (longer than the previous version). 3/4-16 thread size. diameter 74mm to 76mm.
I need to go on a hunt Maybe AI can help me find a few to choose from.
Short version....
HifloFiltro used to make the K&N 171/171C, for K&N.
Then around 2017, K&N went to another manufacturer...
There were complaints about the 17mm nut shearing off, and some other complaints. There was pic posted on another forum, that clearly showed a difference between the original K&N (made by HifloFiltro) and the then newer version (made by manufacturer unknown).
That's when I switched to HifloFiltro. Since then, I can find their quality filters cheaper than HD or K&N... SO I stick with them.
Recently, there have been rumors that K&N went back to HifloFiltro as their oil filter manufacturer. I haven't bothered to do any research about that, because I can get the filter cheaper from HifloFiltro, than I can getting the same filter for more money with the K&N name on it...
I found the pic comparing an older K&N with a then newer K&N, circa 2017ish... (not my pic)
On the left is a K&N 171, circa early 2017, when they were made for K&N by HifloFiltro.
On the right is a new K&N 171, circa later 2017, made by the new manufacturer. The right side filter was one of the then newer K&N filters getting complaints.
Last edited by hattitude; Nov 2, 2025 at 06:00 PM.
Grand HDF Member
Joined: Jun 2017
Posts: 4,558
Likes: 3,889
From: Near Yosemite
Hat, was that the same thread that the 2nd Gen K&N had the stamped louvers on the inside and they looked almost closed off? Or was that a different thread and different filter, lol......??
Seasoned HDF Member
Joined: Sep 2008
Posts: 13,905
Likes: 10,886
From: San Diego, CA
It was a thread on Harley Tech Talk. It was about recent complaints on the K&N filter... I guy compared a new K&N to an older K&N he had on a shelf. He posted that pic and the discussion went on from there.
Over the course of several pages is when the history of the K&N filter was revealed. That was the first I heard about HifloFiltro... That's when I did some digging about HifloFiltro and found it was a high level manufacturer, with a global reputation for good power sports products.
You can clearly see the difference between the filters in the pic above. The HifloFiltro made K&N on the left, IMHO, looks clearly superior (better made) than the one on the right.
I'd never guess they were the same brand and same model number...
Last edited by hattitude; Nov 2, 2025 at 06:59 PM.
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