F-Twins Tech - F800GS Renewing Fork Seals

[drneo66]

Once all the oil is drained out, we want to remove the dust seal. I found a car plastic anchor remover tool was helpful in getting the dust seal to unseat from the fork recess. The biggest thing that you want to do when removing the seal is to take your time and not mar up the rather soft aluminum fork.

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[drneo66]

This is the dust seal removed

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[drneo66]

Next, we'll want to remove the oil seal retaining ring. This is a snap ring that sits inside a groove machined into the fork that holds the oil seal in place. One end of the ring has a notch cut out, allowing us to "hook" a tool underneath it, and gently pry it out.

I chose to use the plastic anchor tool again as not to mar up any of the surfaces. If you need to use a metal tool (be it a screwdriver or a pick), then I would slide the fork tube up, wrap an area with electrical tape, and slide it back down near the oil seal. This will protect the fork tube from any errant damage.

This photo shows the retaining ring removed from above the oil seal.

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[drneo66]

Now we will remove the oil seal. Make sure you eat some spinach Popeye, because we will forcefully pull the chrome fork tube away from the gold top tube. This will pop out the oil seal from it's recess in the fork.

This photo shows the oil seal removed from the fork tube, with a washer and two metal (one silver, one brown) bushings below it.

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[drneo66]

Here's a picture of how all the pieces stack inside the fork.

Note: #1 is closest to where the tire is held on.

1: Dust seal
2: Oil seal retainer ring
3: Oil seal
4: Metal washer
5: Silver bushing
6: Brown/black bushing

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[drneo66]

We want to gently remove each of the pieces. Again I used the plastic tool, twisting in the slot of the brown bushing, and removed it from fork leg.

We can now slide off each piece, making sure to keep them in proper sequence and orientation.


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[drneo66]

This is a picture of everything laid out in the proper order and orientation.

Note: #1 is closest to where the tire is held on and everything is faced down (if you were looking up at the handlebars from the tire's perspective).

1: Dust seal (new seal above)
2: Oil seal retainer ring
3: Oil seal (new seal above)
4: Metal washer
5: Silver bushing
6: Brown/black bushing

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[drneo66]

We can now reassemble the fork. Again, please pay attention to the orientation and order of each of the parts. I use a thin plastic bag, coated in some fork oil as to not tear or mar any seals as they slip over the hard parts of the fork. You can buy special fork tube protectors, but I found that this method works fine and is a bit cheaper.

First, you'll slip on the dust seal (spring facing the axle part of the fork). Then, you slip on the oil seal retainer ring.


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[drneo66]

The oil seal is next, making sure you have the correct orientation. The top "spring and lip" would face towards the axle, whereas the bottom "swimming pool" would face towards the bushings.

The arrow is pointing with the orientation towards the axle.

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[drneo66]

Here is everything on the fork tube in the proper order and orientation.

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[drneo66]

We can now reintroduce the chrome fork tube into the gold top tube. Be gentle and don't force anything. The small amount of fork oil that was on the plastic bag when we installed the seals and bushings should help everything slide.

This picture shows the oil seal pressed into the recess of the gold tube. It is not yet driven down to it's final place.

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[drneo66]

We can now assemble our fork seal driver tool and seat the oil seal into its proper place. It generally doesn't take too much force to drive the seal into its home. A helper may be nice to have here, as you need to hold the axle portion and the dust seal away from the area you are working on.

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[drneo66]

We then slide the snap ring down and pop it into the machined groove in the gold portion of the fork. I found it works best if you get the opposite side of the opening into the groove first, then use your plastic tool to gently push the rest of it down. One way to know if the oil seal is in the proper place, with the snap ring also in the proper place, is to note if the ring will rotate in the groove with a little force. If it does, then everything is where it needs to be.

You want to be sure everything is in the proper place, because if it isn't, your first ride will have you and your bike covered in fork oil.

This is a hard photo to make out, but you can see the snap ring (which pretty much disappears) in the proper place, holding the oil seal.

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[drneo66]

We can now slide down the dust seal. I found that a tiny amount of fork oil or rubber-safe grease helps the dust seal slide into place. Make sure you wipe off any extra on the outside and top of the seal, as we don't want to attract dirt.

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[drneo66]

Now it's time to refill the forks and get them back on the bike.

The 2013 and newer F800GS's WP forks call for an air gap of 61 mm when the fork is fully compressed and the plastic inner damper rod is full. To measure this air gap, you can purchase the proper BMW tool from your dealer (BMW Tool number: 31 6 551), use an aftermarket tool such as Motion Pro Fork Oil tool, or the newly-released Thom Rieck's multipurpose, eco-friendly, and dolphin-safe amazingly wonderful Fork Oil Poker Tool (Patent-pending 2019) available at only the most exclusive of motorcycle dealers for $24.95 , which is also known as a chop stick with a red pen mark at 61mm.

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