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Discussion Starter · #1 · (Edited)
Late last fall, I realized my for oil needed changed when I hit a curb entering a driveway & heard the engine guard hit the front fender. I changed the fork oil over the winter with SE fork oil. There were no leaks prior or after. Repaired the fender only having to add a smidgen of touch up paint after. This past Saturday while riding with the wife, we hit a section of country road that had been torn up & filled with gravel. I heard the fender hit again & sure enough , the son of a bitch is dented again. Suspension feels fine without nose diving. Any ideas? Btw, '09, with progressive spring kit
 

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Unless you put in WAY too much, the fork oil has nothing to do with the total travel distance of the forks. All the oil does, in combination with the internal valving and orifice sizing, is controls the RATE that the fork compresses or extends.

The internal mechanics of the forks is what controls how FAR the forks can travel, and in most cases a stock assembly should not
physically be able to compress far enough to smash the fender.

However, many will claim that what DOES happen, is if you hit a big bump, while at the same time applying the brakes, the fork assembly will actually flex rearward
far enough to smash the fender, which is the only explanation for a fork that won't smash the fender when checked on the lift, but will in the real world.
 

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Clarification on fork oil

You can "stiffen/or/lessen " up the last part of your fork stroke by altering fork oil level. This is a very necessary part of tuning your front suspension in everything except gas shocks/cartridges. This makes the "air spring" work differently. You must first know what you wish to achieve. Adjusting the air spring will not help when you hit so hard that the shocks fully collapse and the oil locks are flush with the check valves. This is a chart on my 30mm cartridges that you may use as an example. You can see how fork oil effects the last portion of the stroke. No, you do not use heavier oil so your forks are impeded from moving quickly, the "valving" is for that & yes, to a certain extent, OEM damper rods have a form of valving that machining & welding can alter.

 

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Yep, Just like Howard said above. If you take out a cm or two it will dive straight into the fender. The opposite is true if you add too much oil it will be extremely stiff. Especially if you have changed to progressive springs that may not be as stiff throughout the compression.

It is a system that works together. Changing any one thing will alter how the overall system changes. There is so little travel that small changes make big differences in this system.

If you didn't set the oil level with the fork off of the bike then you didn't follow the procedure in the service manual. The amount of oil is just a starting point prior to setting the oil level with the fork oil level tool.
 

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Easy, use your head

Purchase an oil level gauge. Remove the steel measuring tube and bring it to your choice hobby store. Find a stiff tubing that comes in 36". Buy a small piece of clear tubing as an adapter. Insert the long piece (one foot or so) over the syringe than try to put in the small stiff tubing inside of the flexible clear tubing. If the small stiff tubing is too small than purchase a small piece of tubing to act as a sleeve to take up the room.

* Install the metal ring around the small stiff tubing.
* Remove the nacelle by the 4 torxs bolts on the side, key switch, and spedo. Set is aside.
* Front Wheel off the ground, than:
@ remove the top chrome bolt (picture below) on the fork tubes (1986~2013 only)
@ Stick the small stiff tubing in the bolt hole and keep sucking until you find the oil level than slide down the metal piece on the small stiff tubing until it hits home on the triple tree to mark the fork oil level.
@ Measure from the bottom of the small stiff tubing to the metal piece using a Grip Jumbo Aluminum Caliper — 24in. Jaw, Model# 59070 found at Northern tool or maybe HF. Mark it down in millimeters & impress your friends.
@ Add some oil by loosing the metal measuring piece and measure from the bottom what oil level you wish to try, tighten the set screw. Suck some fork oil out of the bottle and expel it into your fork tube. Than suck the excess back out until you sound like a kid at DQ.

Repeat the same procedure in the other fork but get both forks the same level.

Tighten the bolts back in the top of the forks but leave the nacelle off and ride to test.

Adjust to suite.







Good luck, it works. :surprise:http://www.roadglide.org/images/RoadGlide_2015/smilies/tango_face_surprise.png
 

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Discussion Starter · #11 ·
Thanks, but I'll just follow the manual. The time it would take me running all over creation to buy that stuff, let alone finding the right size, I could take apart the front end & have it close to being done.
 

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Fork Oil

That is the second reason why I went with the Progressive Monoshock, there is no oil change requirements. The oil in the forks is for spring lubrication/preservation and the cartridge is sealed. No muss, no fuss.
You may wish to consider your slide & guide bushings that have the Teflon coating worn off of them should be replaced every 10K miles & the fork oil that is filthy in the same time period that is lubricating the same bushings should be changed. When your Teflon is worn off of the bushings (shinny clear against the forks) and it will start grinding away on your fork hard chrome. Hard Chrome can never be polished shinny but the steel under the Hard Chrome can. If you see a shinny spot you have worn through the Hard Chrome and are running on the steel tubes. I do many forks for a living and I see this many times. I have included a pictorial on why this happens on FLT's. I do not sell fork tubes nor do I offer general motorcycle maintenance to fix this problem.

It is a fact you need clean fork oil as that oil lubricates your bushings.

I have no monetary incentive to post these facts other than inform our members & yes, I know what I am talking about.
 

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Discussion Starter · #15 ·
Got the leveling tool , pulled the forks & found out that they were indeed a little low on oil according to the manual. Went with the stated amount. Definitely changed the ride. A little more stiff now. Good to go.
 
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