Changing front fork oil
Former Sponsor
Joined: Apr 2007
Posts: 5,360
Likes: 453
From: Davie, FL
Not a Road King but you get the idea. I have a friend who vacuums out the oil from the drain and made a fitting so he could inject the oil up in it using the measuring method. Since most of the forks here on this forum are (bushings & always change the seals) worn out, I recommend using this method found on my site HERE under my DIY
How To R&R Your FL Front End PDF Download
How To R&R Your FL Front End PDF Download
Former Sponsor
Joined: Apr 2007
Posts: 5,360
Likes: 453
From: Davie, FL
Do what you like with your bike
I-Click, please do not take the following posting the wrong way as we have had several off forums conversations. I do lots of these fork changes and I will tell you my experiences. If anyone here disagrees with my methods, it is your bike and I do not ride it, do what you like.
When taking apart a FL late model fork with more that 7,500 miles I see;
If you have 10K miles on any HD forks this is what they look like:
49 mm
Oil out of the 49 mm forks w/10 K miles.
Johnny G forks
When taking apart a FL late model fork with more that 7,500 miles I see;
- The bushings are well on their way to be worn out. Not just a few but all I have seen. Below is a typical example. The Teflon coating is starting to wear through on the inside of the brown bushings (last photo) that are in the top slider under the fork seal and the silver bushing located on the bottom for the fork tube. This was on Johnny G new 07 FLHX with 7.5 K miles.
- The first photo is a set off of a 49 mm Dyna with 10K miles who is also a member here.
- Before reassembling a fork I clean all with contact cleaner including the inside of the fork tube. Look at the seat pipe, it has a ring on it just like a piston in your engine. When using a round brush and swab, I clean out the tube just like a barrel of a shotgun. There is much debris and deposits that come out of it.
- My question who among us thinks that a set of worn out bushings and dirty cylinder walls and dirty oil makes a good situation?
- If you do not inspect your forks how can you know if it is worn or not? Do you think the HD suspension, as poorly designed as it is, will move as freely as it should under these circumstances?
If you have 10K miles on any HD forks this is what they look like:
49 mm
Oil out of the 49 mm forks w/10 K miles.Johnny G forks
Seasoned HDF Member
Joined: Mar 2009
Posts: 24,653
Likes: 9,113
From: Snow Hill, NC
Fast Harley, that was very instructive...I have changed my fuid only but never looked at the insides...Tremendous improvement with fluid change though...I am not sure i would attempt the change on the innerds though...
Seasoned HDF Member
Joined: Apr 2006
Posts: 10,675
Likes: 95
From: Billings,Mt.
That would be ridicules,IMO.
Last edited by 1flhtk4me; Nov 8, 2009 at 08:21 AM.
Cruiser
Joined: Oct 2004
Posts: 245
Likes: 3
From: austin, Texas
Don't put in heavier oil. True, it will help with dampening, but on rebound, that thicker oil has to be drawn through some very small holes, and it will slowdown the rebound, which you don't want. Keep the same weight of oil, but change the springs to a Progressive suspension spring. it will fix all of your problems.
Former Sponsor
Joined: Apr 2007
Posts: 5,360
Likes: 453
From: Davie, FL
I said I do not care what you do. I would suggest that you replace them when they are worn out which you will not know about without disassembling your forks to find out. If you wish to ride your bike with worn out parts than that is up to you, I am only investing my time educating members in a subject that I do for a living.
Seasoned HDF Member
Joined: Apr 2006
Posts: 10,675
Likes: 95
From: Billings,Mt.
Not trying to start anything with you,I appreciate your concern and the time you spent to show us!
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Extreme HDF Member
Joined: Sep 2005
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From: Baton Rouge, LA
I-Click, please do not take the following posting the wrong way as we have had several off forums conversations. I do lots of these fork changes and I will tell you my experiences. If anyone here disagrees with my methods, it is your bike and I do not ride it, do what you like.
Last edited by iclick; Nov 8, 2009 at 12:39 PM.
Ultimate HDF Member
Joined: Aug 2008
Posts: 5,413
Likes: 17
From: eastern oklahoma
there was a thread a couple of months ago about this very topic, you may want to try the search function, as it was a very helpful thread. yes, the screamin eagle heavy is perfect for my streetglide, a similar weight to your roadking, a little bit of weight difference because of the fairing, but i find that the front end feels firmly planted rather than having the marhmallow effect that the stock oil has. i no longer have deep front end dive when coming to a stoplight using the front brake. the screamin eagle heavy works great for me. better control in curves too by the way. and not too harsh at all on the hiway. DO NOT USE THE SCREAMIN EAGLE RACING. just the screamin eagle heavy is fine.
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