fork seal

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skipro3
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Post by skipro3 »

Yup, but no matter what you put in the forks, there will be heat expansion. Therefore the little screw on top of each leg. I use the motionpro air bleeders and I can recommend them. I just tap the little button an couple times a day during a trail ride to releive built up air pressure. Get a set, or add to your wish list along with the spoke wrench so Mama can buy you a gift you could really use.
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Indawoods
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Post by Indawoods »

Sounds like the ticket Ski... I was looking for those and thought White Brothers was distributing those... I will look for them... who sells em?
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skipro3
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Post by skipro3 »

I've seen them in just about every local shop I've been to. To find a dealer near you try this site:
http://www.motionpro.com/Docs/dealers.html

Go to this site,scroll down and notice they come in different heights!!!
http://www.motionpro.com/Docs/mainaccessories.html

Also, I sure wish they made these for my USD forks!:
http://www.faster-motocross.com/fork-adjusters-kyb.html

Since we (I) are talking tools, then here's what a "real" spoke wrench looks like. See how it wraps around the nipple: (Scroll down the page about half way to see it)
http://www.motionpro.com/Docs/convtools_2.html
Jerry

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IdahoCharley
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Post by IdahoCharley »

The seal savers do work well and you do have to remove the fork from the triple trees and slide them over the top. Dipping them into water makes them slide on easy. I run them on for the last 7 years on other bikes and they do keep the seals a lot cleaner than anything else I've tried.

Moose makes a seal saver (forkskin) which is about 50 percent thicker than the 'Seal Saver' brand. Summer Racing Components make one that also thicker than the 'Seal Saver' brand. When your selecting them you will want the 44-55mm or the 1 3/4 inch seal savers. (Some of their literature is a little confusing on the sizing). Summers Racing Components also may a long one which can be cut in half and used. I like this because one pair becomings two pair and equals less dollars out of my pocket - although the SRC brand are more expensive to start with.

Concerning inverted fork and the mud deflector used with seal saver type products. On my KTM I take a small section of clear tubing slip a zip tye through the center and then wrap it around the seal saver to hold it in place. The tubing then contacts the lower fork guard as the fork is compressed and eliminates contact with the seal saver. This stops the lower fork guard from quickly wearing through the seal saver where it mounted to the upper tube. Make sense??? Sort of replaces the function of the metal circlip on the upper forks.


Fork Bleeders - These are great items also. Have installed the type that replace the stock bleed screws and also have installed the Motion Pros where you need to drill and tap the cap. Both types work well but the Motion Pros are a lot stronger due to their increased thread size where they screw into the cap.

It is important to note that if you do install these they DO NOT remove the necessity that the fork is fully extended prior to bleeding. Otherwise you are effectively reducing your effective air gap and making your forks harsher.
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skipro3
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Post by skipro3 »

Too little air and they are harsh too huh? Didn't know that. Thanks for that tip. I knew from experiance that built up air pressure makes things harsh. I usually hit the button and bleed with the forks at regular sag height (Me, on bike, stopped and feet on the ground.)
Also, I bleed them just before riding since most of my riding areas are at higher altitude than my garage.
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Post by IdahoCharley »

Skipro3 - when you set your oil height what you are creating is an air gap or air space in the upper part of the fork. This air space is part of the fork's design. As the fork compresses part of the resistance to the compression is the spring, part of it is the trapped air volumn. The rate of compression is due to both the hydraulic flow of oil through the base valve and the spring rate. The contribution of trapped air volumn is significant - the relationship is P1/V1 = P2/V2. If you were to start with an atmospheric pressure 15 psiA and compress the forks half-way through their air gap you would decrease the space available for the air and the relative pressure would double. (30 psiA per fork leg) If you compress the forks to 1/8 the available air space your pressure would be 120psiA per fork leg. This is the relationship which allows relatively small changes in oil height to play such a large role in adding bottoming resistance to our forks.

Now if your forks are compressed slightly due to the bike's weight (and/or the rider's weight) and you bleed the air out of the air space in your forks you have now changed the effective air space/volumn/pressure. Hence all the air chamber volumn/pressure relationships will be out of wack. Your forks will ride lower in their stroke and therefore response differently. Your bottoming resistance will change.

NOTE - The oil height we set on our forks is a reference point and does not equal the real air space or trapped air volumn within the fork leg. I hope this note is understandable. Charley
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Post by skipro3 »

O.K. from now on I will unweight the forks to full extension before bleeding the air. I've complained of harshness on small, high speed hits. Maybe this is the reason! Thanks again Charley!
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Indawoods
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Post by Indawoods »

It sounds like you have done a lot of research on this Charley, and your formula makes sense. With the KDX's original setup you only hoped it would pump up! :lol:

When I was a youngster, there was no changing anything... you took what the manufacturers gave you. No jetting or springs changes, and change the fork oil? Whatever for?

The internet has really opened my eyes over the years to the need to maintain your bike to top shape and a bike needs setup for the individual for how and where they ride.

Of course when I was a kid, I'm sure my dad didn't want to put any more money into my bikes than what he had to. But then again, I didn't know anyone who would buy anything but the cheapest tires they could find when one wore out.

Thanks for your input, we appreciate it.
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"People ate cows a thousand years ago for the same reason we eat them now. Cause they are easy to catch.We're not savages,we're just lazy. A cheetah could taste like chocolate heroin. But will never know. Those bastards are fast!!! "
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