Why Dynas use longer oil filter?
Club Member
Joined: Jun 2007
Posts: 45,429
Likes: 2,898
From: Bedford UK
The correct numbers for short and long are in post #
Stellar HDF Member
Joined: May 2009
Posts: 2,856
Likes: 127
From: Middle of Kansas
If you go to the Harley web site, and look for filters, they list the low filtration filter for EVOS up thru 98. For 99 on, EVO's and Twin Cams, they list the high filtration filter. But, as stated before, I don't think anything changed between the 98 and 99 EVO's to warrant the filter change. I do know that the 99 EVO's did come out with the later filter on them. And, Harley still recomends them as an upgrade for the older engines.
Elite HDF Member
Joined: Sep 2007
Posts: 4,468
Likes: 12
From: Bluffton, South Carolina
Just a quick note to explain why the by-pass pressure setting is important. The by-pass does just what it's name implies. It allows oil to by-pass the filter if the flow is impeded and the pressure builds. While a harley will have it's oil changed frequent enough where that probably won't be a problem you could have other issues. Ee've built a lot of small and big block engines in the past and at one time we had a few engines grenade. What we found was the "name brand" filter had changed it's supplier and the filters were not the paper type, but "rag or cloth type". The rags moved and clogged the filter and even though the py-pass opened it would not supply the engine at 7,000+ RPM's. Many of the cheaper filters are rag type, I would not reccomend using that type of filter.
The difference in the number of microns in a needle/ball bearing is not as important as a babbitt bearing engine as the roller wil roll over either of them. A babbitt beraing can imbedd the material in the bearing surface and score the adjecent bearing surface which can cause pressure loss and eventual engine failure. Hope this helps.
The difference in the number of microns in a needle/ball bearing is not as important as a babbitt bearing engine as the roller wil roll over either of them. A babbitt beraing can imbedd the material in the bearing surface and score the adjecent bearing surface which can cause pressure loss and eventual engine failure. Hope this helps.
Road Warrior
Joined: Apr 2007
Posts: 1,952
Likes: 15
From: Senoia, Ga., by way of Miami, Fl..
John's explaination makes sense.. As many know, I've chased a "tick" on my bike for quite some time... Runs great and I typically dont focus on it till it gets cold.. However, long story short, I noticed this tick after changing my rocker gaskets. At this same time, I filled the case with Valvoline MC oil and used an HD filter that I'm pretty sure, thinking back on it, was a Twinki filter. Having since done the lifters, push rods, machined the heads and inspected for problems, replaced the rings and felt for play in the rods, replaced the cam bearing and measure the gears, and then replaced the compensator, I'm now leaning towards rockers, shafts and maybe lower boxes this winter. My reasoning is very close to John's regarding bushing wear.. You'll never find a twinki filter on my EVO again..
Tourer
Joined: Apr 2010
Posts: 293
Likes: 7
You want the correct air pressure in your tyres.
You need gas in the tank.
The bypass valve should suit the application.
None of the above relate to the number of microns that a filter is rated at, nor to the suitability of any given micron rating to any given application.
The filter CLEARLY has nothing at all to do with any "tick".
No doubt your local reseller is glad you do your own work.
You need gas in the tank.
The bypass valve should suit the application.
None of the above relate to the number of microns that a filter is rated at, nor to the suitability of any given micron rating to any given application.
The filter CLEARLY has nothing at all to do with any "tick".
No doubt your local reseller is glad you do your own work.
Road Warrior
Joined: Apr 2007
Posts: 1,952
Likes: 15
From: Senoia, Ga., by way of Miami, Fl..
You want the correct air pressure in your tyres.
You need gas in the tank.
The bypass valve should suit the application.
None of the above relate to the number of microns that a filter is rated at, nor to the suitability of any given micron rating to any given application.
The filter CLEARLY has nothing at all to do with any "tick".
No doubt your local reseller is glad you do your own work.
You need gas in the tank.
The bypass valve should suit the application.
None of the above relate to the number of microns that a filter is rated at, nor to the suitability of any given micron rating to any given application.
The filter CLEARLY has nothing at all to do with any "tick".
No doubt your local reseller is glad you do your own work.
Last edited by HGM; Nov 15, 2010 at 05:08 AM.
Tourer
Joined: Apr 2010
Posts: 293
Likes: 7
Twin cam filter is on the feed.
Evo filter is on the return.
The bypass valve has nothing to do with oil feed on an evo. It would cause wet sumping, not a tick.
See, even though you tried to be rude to me, I am still willing to help you.
The bypass valve on a twincam filter could hardly be set to the same pressure as on an evo filter, or else why would the oil pass through the filtering medium?
This is hardly a huge revelation, but rather common sense, requiring no real mechanical knowledge at all.
People that go on and on about the bypass valve are wasting their, and others, time, as that is not the issue. But it sounds good to them to keep saying it, apparently.
And here's the news.
Some things are impossible, and some things cannot be caused certain things.
But you need a strong understanding to know that.
Evo filter is on the return.
The bypass valve has nothing to do with oil feed on an evo. It would cause wet sumping, not a tick.
See, even though you tried to be rude to me, I am still willing to help you.
The bypass valve on a twincam filter could hardly be set to the same pressure as on an evo filter, or else why would the oil pass through the filtering medium?
This is hardly a huge revelation, but rather common sense, requiring no real mechanical knowledge at all.
People that go on and on about the bypass valve are wasting their, and others, time, as that is not the issue. But it sounds good to them to keep saying it, apparently.
And here's the news.
Some things are impossible, and some things cannot be caused certain things.
But you need a strong understanding to know that.
Road Warrior
Joined: Apr 2007
Posts: 1,952
Likes: 15
From: Senoia, Ga., by way of Miami, Fl..
Not knowing the bypass pressure and volume of each engine, your statements do make sense. However, using your theory instead, is it not still possible to possibly cause oil cavitation due to the wet sumping? Oil aeration in other engines can be the route of a tick. It actually traps air behind the main bearings, causing a tick on each stroke. Realizing this engine is different, the rockers ride on bushings and I dont think it can be ruled out. Remmber, I've been everywhere else and am reaching quite a bit, but its not impossible. It may not be the relief, but the filtration is a problem. Even the MFG advises against it. MY thoughts are also questioning the volume of flow through the filter and bypass and how it effects the pressure regulator and overall oil volume to the top end..
So, even though some things may seem impossible, they may not be. As an example, I've seen many people through $5k at a diesel engine only to find out that the oil they were using caused the missfire...
After changing and checking everything else, including the filter, I'm left with a very small list of parts for the potential source. Trusting my work and having been in there multiple times with no change, the bushing wear (BTW, they appear fine) inside the rocker boxes is about all I've got left.
Thanks for the input.
HD Forum Stories
The Best of Harley-Davidson for Lifelong Riders
7 Surprising Harley-Davidson Products that Are Not Motorcycles
Verdad Gallardo
8 Best Harley-Davidson Motorcycles Ever
Pouria Savadkouei
10 Worst Harley-Davidson Motorcycles Ever
Pouria Savadkouei
Killer Custom's Jail Break Is The Breakout That Refused to Blend In
Verdad Gallardo
Crazy Bunderbike Build Looks Amazing, But Is It Impossible to Ride?
Verdad Gallardo
Harley-Davidson Reveals Super Cool Cafe Racer Concept
Verdad Gallardo
Engraved Rebellion: Inside Bundnerbike's Glam Rock II
Verdad Gallardo
10 Motorcycles You Should Never Buy
Joe Kucinski
10 Things Harley-Davidson Needs to Fix in 2026
Verdad Gallardo
Road Master
Joined: Nov 2006
Posts: 1,227
Likes: 3
From: Central Illinois
The bypass is not the issue. The spring and valve in the filter is there to maintain oil in the filter after shut down. The TC and Evo use different micron filters because the TC eliminated the tappet screen that filtered top end oil. The Dyna used a longer oil filter to correct oil capacity because the oil pan was reduced in the back to fit the "dyna" cad designed frame. Simple as that.
Grand HDF Member
Joined: Mar 2007
Posts: 4,922
Likes: 265
From: Deep in the heart of New Jersey
I believed the 5 micron filter rating was due in part of the cam chain tensioners. And the fact twin cam motors use piston oilers. If and when the cam shoes start to shread off pieces, it could clog the piston oilers and other oil passages. In my opinion you can't have enough oil filter on a Harley.Now if they could mount them so the don't dump all over the front of the bike when you change them,,,.