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Punisher660

Fork seal procedure?

18 posts in this topic

I need to change a fork seal on my 04 WR450 - I have never done it before, though I have seen it done. But you know how it is, see one, do one, teach one.... I need to do this one on my own, but is there a tutorial or a write up on changing the fork seal? Are all inverted forks pretty much the same?

I know it should be an easy job, any tips?

(Sorry, search was disabled)

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I think it was Clark4131 who did a good write up on changing fork seals, hopefully he might re-post it if the search feature isn't working still. Sorry I can't be much more help if nothing else it might shorten your search when things are back to normal

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I think it was Clark4131 who did a good write up on changing fork seals, hopefully he might re-post it if the search feature isn't working still. Sorry I can't be much more help if nothing else it might shorten your search when things are back to normal :thumbsup:

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This will be short form, so fall back on the manual for details:

> Loosen the upper clamp pinch bolts, then loosen the fork cap. This way, you won't need to clamp the forks in anything to get the caps loose later.

> Remove the forks from the clamps. BACK OFF BOTH compression clickers until they stop. Remove the caps from the tubes, push the spring down, and loosen the jam nut on the damper rod. Unscrew the cap from the rod and remove the cap and associated parts, the spring, and the compression valve push rod (in the damper rod)

> Dump the fluid out into a pan, and stroke the dampers several times to pump them out.

Note: You do not have to remove the base valve or damper assemblies to replace the seal(s). You can clean the valve a lot better with it out, but that's not specifically necessary to the job at hand.

> Push the dust seal out of its pocket using a small screwdriver. You'll find a black wire retainer ring under it that has 4 loops in it. catch a loop with a small screwdriver and pop the ring out. Using the two fork tubes as if they were a slide hammer, extend the tubes sharply with a fair amount of force. The inner tube head will drive the seal up and out of its pocket. Carefully remove the bearing ("metals") from the tube and slide the old seal off.

> Inspect the inner tube for scratches, nicks, or burrs that you can feel with your fingernail, and sand them out with 280/320 grit. If you can feel it, It will cause the new seal to fail. Clean the dust seal, clip, etc., and slide them back on.

> IMPORTANT: The new seal must be protected from the sharp edges on the end of the fork tube where the bearing goes. There is a plastic cap tool made for this, but any piece of a plastic bag will do. I use the bag the seal comes in. Put the bag over the fork tube, smear a little grease on the seal, and slide it on. Replace the lower bearing.

NOTE: From this point on until the caps are back on the rods, DO NOT EXTEND the inner fork tube more than 8 inches out of the outer tube. If you do, you can catch the lip of the seal on a machined edge on the tube and damage it. You've been warned.

> Use a real seal driver. They're worth it. You can use the driver as a slide hammer to drive the seal in, or stand the fork upside down on a block of wood, push the axle lug against the driver, and bump the bottom of the fork with a soft mallet. Check the depth of the seal. The snap ring must seat easily. Snap the ring in place, then put a small amount of grease under the dust seal and press it back in.

> Compress both the rod and tube assembly completely and fill it to the top. Work the outer tube up and down NO MORE THAN 8 INCHES a few times. Then work the dampers a Full Stroke until there is no longer any slurping noise from air in the dampers. If the oil level drops below the top of the damper, you will want to add more oil. Replace the springs and push rods and screw the caps in place. The caps need to be run down all the way until they stop against the tops of the damper rods, then run the lock nuts down. Tighten the caps once the fork is clamped in the lower clamp, reversing the way you took them off.

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I think it was Clark4131 who did a good write up on changing fork seals, hopefully he might re-post it if the search feature isn't working still. Sorry I can't be much more help if nothing else it might shorten your search when things are back to normal :thumbsup:

Nope, wasn't me, but I've seen one around, author unknown. If I find something, I'll post the source...SC

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Thanks Gray - I can picture all the steps as you described them and it should be a piece of cake. I think I will either shoot a video or do a step by step with pictures and your writeup for other noobs on this one. :thumbsup:

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I ask this question out of pure curiosity. This is not a flame or sarcasm.

Why isn't the manual good enough for doing service on your bike for topics like this one?

Obviously if your doing a mod, the manual won't help, but fork seals, oil changes, replacing clutch, top-end rebuilt...this is all covered in the manual.

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First of all - I did not get a manual with my bike so I don't have all of the info.

Second - there are a lot of people that are intimidated by some of these jobs and what I have seen of the manual, it is not the most user friendly book written. In my personal opinion, it is always easier if you have some color photos or video to walk you through this step by step as opposed to the black and white schematic drawings in a manual, not only is it easier to follow, but does not seem as intimidating of a job either.

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First of all - I did not get a manual with my bike so I don't have all of the info.

Second - there are a lot of people that are intimidated by some of these jobs and what I have seen of the manual, it is not the most user friendly book written. In my personal opinion, it is always easier if you have some color photos or video to walk you through this step by step as opposed to the black and white schematic drawings in a manual, not only is it easier to follow, but does not seem as intimidating of a job either.

Thanks for the reply. As I said, I was curious.

For me, I think the Yamaha manual is awesome and wish every motorcycle company gave you a service manual when you bought a bike. I also think my work experience as an Engineer gives me a bias opinion towards the manual. To me the manual just makes sense, but it's good to hear what other people think as I have to sometimes write manuals and standard work instructions in my job, it's important to know how other people view those instructions.

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No Problem. Some of us just are not that mechanical and really need someone to walk us through it. I am one of those that has to see something done before I trust myself to tear into it with only a manual. (Thanks for the link Limy BTW)

I just figured that we have seen posts and writeups for simpler things such as changing tires, this one might be seful as well. Just my .02 and I figured since I am going to do the job anyway, its not much more effort to either tape it or take photos.

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The service manual can be a bit difficult to follow at times. The oil refill and level adjustment procedure for the forks is a good example of that, actually. Reading it for the first time, it was less than clear, even to me. Technical writing from Japanese to English must be exceptionally difficult, because I've never seen it done very well.

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I agree with Punisher. The Yamaha manual explains this lengthy process in about 50 words. It will say "Use Yamaha part number xxxxxxxx-xxxxxx to press the seal into the outer tube" w/o any mention to what you should actually do. That's the difference between the Yamaha book and a good tutorial. Yamaha says what you do and a good tutorial shows how you do it. If you've done forks before, you'll know that the seals don't just slide home w/o some muscle. I was worried I'd damage the inner tubes coating.

Anyhow, I couldn't find the color-illustrated tutorial I used, but here's another text-only version that's pretty clear. http://www.thumperfaq.com/fork_seals.htm

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