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[Fired00d]

Sure am glad I went w/the K&N yesterday when I had the bike serviced. [smiley=huepfenjump3.gif]

 [smiley=pumpkin.gif]
Ride Safe,
Fired00d
 [smiley=fireman.gif]

[Midnight Rider]

After exhaustive head scratching, I remembered where I read the filter test.  American Iron Magazine ran a series of articles by Donny Petersen about oil, and then about filters.  If anyone cares to read thru some of Donny's articles, they are available on his web site: http://www.heavydutycycles.com/techsect.htm   The filter bypass info is in the 3rd article on oil filtration listed on the referenced link.

The information on the filter bypass is copied here.  Also note in the table the difference in the surface area of the filter media between the K&N and the H-D filters.
---------------------
Filter          Part #         Bypass valve         Filter area
K&N           KN-171C        [highlight]14psi[/highlight]            [highlight]164sq.in.(73"x2.25") [/highlight]
Fram         PH6022         12psi.           101sq.in.(45"x2.25")
Amsoil        SMF134C      12psi.           106sq.in.(47"x2.25")
A/C Delco  PF53             10psi.             96sq.in.(55"x1.75")
H-D          63731-99       [highlight]10psi. [/highlight]           [highlight]63sq.in.(36”x1.75”)[/highlight]
---------------------
BTW - the "bypass pressure" is a pressure differential, not actual oil pressure as measured on your gauge.  

Jerry

Thanks for the info, Jerry....geez,the K&N has nearly 3 times the surface area...that is a significant differerence!!  Glad I switched!!

[HWYMAN1]

As usual I am truly amazed at the amount of knowledge and dedication to finding information on this website ( it is why always love to read stuff here!). Harley probably view this website like many people view Ralph Nader. But back to the filter issue, I guess we need to be careful if we put a K&N filter on, because if stock HD filter filters at 5 microns ( though we know it doesn't), and oil is 8 microns, if we suffer an engine failure, the MOCO will blame it on the K&N filter for actually filtering the oil for the engine!!!!!! Oops, I guess I got carried away, so I will step off soap box, but thanks to all the research gathers it never leaves any stone unturned or have dull moments.  John

[RATKING]

Hi Jerry,

   The tech articles on the Heavy Duty Cycles webpage
( http://www.heavydutycycles.com/techsect.htm ) make for some excellent reading.  I remember some of these articles appearing in American Iron Magazine, but having them all in one place makes it easy to reference.  In looking at the article on filters, I was surprised on the multi-pass theory being used, contibuting to unfiltered oil circulating many times before all the oil is filtered and contaminants are removed.  I replace the by-pass plate in all my rat-motor rebuilds
(Chevy Big Blocks), and just drive them easy until the oil is warm.  I can also read when the filter needs replacement because of the drop in oil pressure.  Harley made a big deal about the Twin Cam oiling system being changed/improved by filtering the oil before it goes to through the engine.  That is great, as long as the by-pass is not open allowing the oil to bypass the filter altogether.  I was not aware of the K&N's higher bypass valve setting.  I have been using them just becasue the nut on the end makes them significantly easier to remove.  But with the higher by-pass valve setting, and the much larger filter media, it is clearly the filter of choice for our Harleys.    

[electraglideclyde]

Thanks for all the great info. I remember reading the article in American Iron. I'm due for an oil change this weekend and it will be a K&N filter with Mobil 1 . [smiley=xyxthumbs.gif]

[AUSSIE_FLSTFSE]

I hope this isn't a stupid question, but all this pressure & bypass pressure talk is starting to confuse me. So when using a feuling pump & the oil pressure never getting below 30psi & average about 60psi is any oil getting filtered or is it all bypassed? Or am I just reading this wrong?

Cheers
Aussie

[grc]

I hope this isn't a stupid question, but all this pressure & bypass pressure talk is starting to confuse me. So when using a feuling pump & the oil pressure never getting below 30psi & average about 60psi is any oil getting filtered or is it all bypassed? Or am I just reading this wrong?

Cheers
Aussie

Aussie,

It is confusing because of the terminology used, but what it really refers to is the pressure differential due to the resistance created by the oil flowing through the filter media.  It doesn't matter if your oil pump puts out 30 psi or 60 psi, because you are only looking at the difference in pressure at the inlet and outlet sides of the filter. Think of it as a pressure drop valve. This is a safety feature that will route oil to the engine (dirty oil is better than no oil) in cases where the filter gets dirty, or you have a heavy weight oil and a cold engine, etc. (another good reason to avoid straight 50 wt oil in cool weather).  One of the reasons I switched to K&N filters was the bypass setting, but just as important is the amount of surface area.  With almost three times the surface area, combined with the bypass setting, even with a higher micron rating than the H-D filter the K&N over time will filter better and longer.

I'm a lot better at doing than I am at explaining - I hope this helps.

Jerry

[HWYMAN1]

GRC,
Actually it is a pretty good explaination. Makes sense that primary function is to maintain getting oil to the engine ( whether through filter or not!)  And I have no mechanical inclination. thanks, john

[AUSSIE_FLSTFSE]

Jerry,
Thanks that helped alot & my next filter will be a K & N & Mobil 1 V Twin oil. I will unload my last 4 quarts of Syn3 & genuine HD filter to someone I don't like!

Cheers
Aussie

[AUSSIE_FLSTFSE]

Sure am glad I went w/the K&N yesterday when I had the bike serviced. [smiley=huepfenjump3.gif]

 [smiley=pumpkin.gif]
Ride Safe,
Fired00d
 [smiley=fireman.gif]

But d00d, what oil did you use?

Cheers
Aussie

[Fired00d]

But d00d, what oil did you use?

Cheers
Aussie

Went with Amsoil in Motor, and Redline in Tranny/Primary.

 [smiley=pumpkin.gif]
Ride Safe,
Fired00d
 [smiley=fireman.gif]

[grc]

........
............................ [highlight]I will unload my last 4 quarts of Syn3 & genuine HD filter to someone I don't like![/highlight]

Cheers
Aussie

[smiley=thumbsup.gif]    

I guess if no one wants it, you could always use it in the primary or use it to flush the engine prior to winter storage.  I've still got a quart on the shelf too, figured I'd keep it as a memento, along with the other "take offs" from the bike.  

Jerry