How To - Change Oil & Fork Seals On A Dual Chamber Type Fork (part 1) Video

How To - Change Oil & Fork Seals On A Dual Chamber Type Fork (part 1)

If you need to replace the fork oil and fork seals on a modern dual chamber type fork, but could use a little help, you’ve come to the right place. Our informative video will walk you through how to change the oil and fork seals on a Modern dual chamber type fork in a short amount of time. Watch our industry expert as he changes the oil and fork seals on a Modern dual chamber type fork. Rocky Mountain ATV/MC is your online information source for several online videos that provide step-by-step instructions. Trust us to have the answers and instructions you need – every time.


This instructional video is for dual chamber style forks. Most modern Showa and Kayaba motocross forks are dual chamber style. You can tell whether or not they are by looking at the fork cap. The fork cap on dual chamber style forks has two pieces; one for the outer fork chamber and one for the inner chamber. If your fork is not a dual chamber style fork, refer to our cartridge fork seal replacement video.

Hi, I'm Eric from and today I'm going to show you how to change the oil and fork seals on a modern dual chamber type fork.

To start off with we'll need a clean work and clean rags, Tusk cap wrenches, Tusk seal driver, Motion Pro seal bullet, Tusk fork seals, Race Tech suspension grease, and most importantly, service manual. This is where the critical procedures and specs will be found. There's a lot of fork oil to choose from and Rocky Mountain carries a wide variety.

The first thing we're going to do is we're going to use our fork cap wrench and we're going to loosen the outer fork cap. This is a lot easier to do if you do it while it's in the bike still. Just go ahead and loosen the top pinch bolts on your triple clamp and then break it loose and then you can finish taking it off when it's off the bike.

Slide the outer tube down a little bit and dump out the oil.

Go ahead and let that drain. Mostly oil out of the outer fork tube. You notice that there's two holes on that inner cartridge and we want to make sure we get the oil out of those too. Go ahead and rotate it around so those holes are down, let all the oil get out of that inner cartridge also.

We're going to go ahead and temporarily install the outer fork cap.

Using soft jaws go ahead and install the lower fork and vice using the axle boss or Caliper carrier. In the center bolt, back off the rebound adjuster all the way. During assembly, the center bolt will need to thread all the way onto the damping rod and having the rebound all the way out will allow this.

We're going to remove the center bolt from the lower fork leg. Thread that out. It's going to remain attached to the damping rod and we're going to take our fork cap wrench, we're going to grab the top of the fork and push it through and slide that tool behind the center bolt lock nut.

Next, we're going to remove the center bolt from the damper rod. Go ahead and back out off the lock nut from it. We'll remove that all the way off.

Inside is the push rod. We're going to go ahead and remove that carefully and lay it down on our clean rag.

Then we're going to push back in on the top of the fork and remove our tool. Let that rod back in carefully. Now we're going to go ahead and remove the dust seals. Just take a flat blade screwdriver very carefully slide that off. There's an inner ring in there. Once again very carefully not to scratch our inner fork tube.

This seal retaining ring needs to come out or else the fork will not come apart.

We're going to go ahead and remove it from the vice and we're going to remove the outer fork cap. Slide down the outer fork tube all the way. We're going to carefully remove that inner cartridge and set it out on our clean rag. There's going to be a little bit of oil coming out. Just be careful. There's also a spring guide in there that needs to come out. Now to get the spring out, it's easiest just to dump it upside down. The rest of the oil is going to come out along with the spring, and lay that spring out on your clean rag also.

It's a good idea just to let the rest of the oil get out of there.

Now, it's time to remove that seal. You can just slide it up, just kind of see where you're going to need to slide it to and go ahead and give it a couple firm pops and the seal and the inner bushings will all come out.

Now we're going to go ahead remove those bushings from the inner fork tube. You kind of need to get your fingernails in there and spread it. It is a slit. Set all these parts out on your clean rag in order and also take note of how they came out, what sides facing up. Slide the old seal off. There's a little lip right there that you need to be really careful when you put the new seals and new bushings back on. Don't forget your dust seal and that inner retaining clip. Now's a great time to refer to your service manual for fork part inspection to get ready for assembly.

For assembly you need to start first with the seal bullet. We're going to slide that on the end of the fork tube. This protects the seals from the sharp edges. Grease up the dust seal. Slide that over. You're going to need your retaining clip also. Slide that down.

Now we're going to go ahead and install some quality fork seals. We're going to grease them up real good so they slide down easy. Have a good initial seal. Be careful of that sharp edge. Go ahead and remove the seal bullet and we're going to go ahead and put the washer on, sits on your seal, the outer bushing, it slides down also and then the inner bushing. The inner bushing, you might need to spread apart again and slide into that groove.

Once all that's installed, it's time for the outer tube. You want to make sure that's nice and clean. Slide that down. And we're going to go ahead and grab our Tusk fork seal driver.

First thing we're going to do is take that washer and that inner bushing and just seat them. We're going to lightly seat them in there and you can hear the driver bottom out a little bit, kind of more of a metal to metal sound. You'll be able to tell when it's seated.

You're still holding the upper fork tube at this point. Now we need to actually slide, we're going to install that seal with the seal driver again. And the same deal, you're going to be able to hear that bottom out where it needs to go. It doesn't take a lot of force, but it does take some.

Now its time for your inner retaining clip. Slide that in there and you can use your seal driver again and you can hear it click when that slides in. Just a little tap and it'll slide in. Now using your fingers, seat that dust seal.

Okay, now we're done with the outer fork tube. We're going to concentrate on the inner cartridge assembly. That and final assembly will be addressed in part two.