The Harley service manual calls for a 10 micron minimum oil filter.

The wix filter is a 5 micron filter. So it is more than good enough.

Hopefully you will get an answer on the difference.

 

I've been looking around at different company sites, K&N, Napa and JP cycles. entered each bike in and all gave different part #'s for the two. Not sure if its a big deal or not, I just don't want to tear up one of the bikes. Especially hers LOL!

 

www.bobistheoilguy.com does everything oil, lube, filter related in great detail. They cut open a harley brand filter an said it was well made an good quality. They said it was better than the the amsoil filter (which had less filtering material).