Author Topic: Harley Davidson "5 micron" Oil Filter Statement And Aftermarket Oil Filters  (Read 761 times)


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For those of you out there confused about Harley Davidson's "5 micron" oil filter statement and what exactly that means, rest assured your not the only one. The "5 micron" statement alone is meaningless without a percent efficiency rating, which they fail to mention on their website and other marking material produced today. You have to go back to a 2008 Harley Davidson Parts and Accessories catalog to find the 5 micron statement labeled as nominal rating.

Nominal rating usually means the oil filter can stop a percentage, usually 50 percent, of particles greater than the specified micron size. A spokesman for Amsoil said all oil filters on the market, even the cheaper one's like Walmarts Supertech oil filters will filter down to 1 micron, but without the efficiency percentage the micron rating is useless for describing performance. For example, any cheap oil filter manufacturer could use the statement '1 micron' in marketing material, and leave out the fact that only a very small percentage of particles that size are stopped by the oil filter.

The nominal rating isn't used much by oil filter manufactures. It's discouraged from use because there are variables that can change from one test to another making the rating inconsistent and a bad rating to use when comparing different oil filters. For some reason Harley Davidson does not provide the more accurate "Absolute Rating" for their oil filters.

Both Fram and Amsoil oil filters use an absolute efficiency rating system to rate their oil filters, and the ISO 4548-12 standard is used for testing. The Fram Extra Guard line of oil filters, which are the line of Fram filters sold for many motorcycles, ATV and UTV vehicles are 95% efficient at 20 microns. The Amsoil filters are 99% efficient at 20 microns. This means the Amsoil oil filter can stop 99% of particles 20 microns or larger in size, and the Fram filter can stop 95% of particles 20 microns or larger in size. A Fram tech support person, who had access to a specification sheet for the Fram PH6022 oil filter used on many Harley Davidson twin cam and Milwaukee 8 engines, said the Fram PH6022 oil filter has a nominal rating of 10 micron at 50 percent. I'm not sure how well Harley Davidson's oil filters compare to the Fram and Amsoil filters. My guess is they are better than Fram and equal to or not as good as Amsoil filters.

Don't let Harley Davidson's statement about their oil filters confuse you when considering an aftermarket filter. Amsoil, Fram, NAPA, WIX  all sell good quality oil filters. Just make sure the oil filter is recommended for your motorcycle by the oil filter manufacturer and follow the motor oil and oil filter change intervals recommended for your motorcycle. You can save a lot of money using aftermarket oil and filters for your bike, and it won't void your warranty. It is illegal for a motorcycle manufacturer to void your warranty for using aftermarket motor oil or oil filters unless the motorcycle manufacturer demands you used their brand and supplies the products for free.

Here are some pages I scanned from 2 different Harley Davidson Parts and Accessories catalogs. One catalog is from 2008 and the other is from 2017. The SYN3 synthetic oil Harley Davidson sold in 2008 was actually a blend, but they never used the word blend or full in marketing material. The oil filters look the same in 2008 as they do in 2017, but they may have changed oil filter manufacturers. I'm not sure. I couldn't find any mention of the 5 micron statement being a nominal rating in the 2017 catalog.

Click image to enlarge:

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2008 Harley Davidson Motor Oil

2017 Harley Davidson Motor Oil

2008 Harley Davidson Oil Filters

2017 Harley Davidson Oil Filters
« Last Edit: December 19, 2020, 06:43:57 PM by adminjoe »
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