I recently had to replace the RH fork seal on my 2016 R1200RS (Premium with ESA suspension, Mileage = 25K). After looking at several forums, this thread was the most comprehensive, short of explaining how to replace the fork seal. I thought I would add my observations on replacing the fork seal to this thread to add a little more depth for when others might have to go through this process.
Thanks to all who contributed to this thread, it helped out immensely. I know I am cross threading on the R1200R forum but since R and RS are paternal twins with different (or no) clothing and they share the same forks; I thought it would still be applicable.
YouTube has several good videos on how to change the fork seals on Up Side Down (USD) forks, so I won’t go into the blow by blow on how to replace the seals. What I will try to explain what I experienced that is unique to these forks and the seals I used.
Ultimately I used SKF KITB-46Z seals and MOTUL 7.5wt oil. Overall I do not feel any discernable difference from the previous seal/oil setup, after 200+ miles of riding.
I tried to use the All Balls Racing fork seal 55-135 (as recommended on the All Balls Racing website) but the problem was that it did not
fit. It is the correct diameter but the height is too high and I could not get it to seat low enough so that the retaining ring could sit properly in the notch on the upper fork tube. After noticing that the BMW seals (i.e. fork gasket set 31-42-8-584-880) kit was common to the 2016 S1000RR, I looked at All Balls for the seal for a S1000RR. The recommendation was for the 55-156. I am not sure if they work or not, I went with a different brand.
I did find an R1200RS thread where Ted Porter’s Beemershop in Scotts Valley, CA recommended the SKF KITB-46Z seals as an alternative for the BMW set. For $36, the package contained a dust seal and an oil seal for one fork. If you are doing both forks, you will need to buy 2 sets, which is still cheaper than the $94 that BMW wants for their full fork set. When I picked them up, Ted recommended buying the two sets since he stated there is less stiction than the OEM seals. Since I was only focused on the RH fork and the LH fork does most of the work anyway, I took a pass and only bought the one set. Long story short, I cannot tell the difference but I am sure Ted knows what he is talking about.
I used the MOTUL 7.5wt oil since it has almost the same viscosity at Reported cSt @40C as the Shell Advanced 10wt (35.3 and 38.97 respectively). I did not see the viscosity for the BMW 11.5wt on the chart but from what I gather the BMW fork oil is really Shell Advanced, the BMW 11.5wt should not be too far off from the Shell Advanced 10wt. My RH fork took about 2/3 of a liter to get to the recommended 80mm air gap. You will need two bottles of oil if you are going to both forks.
One difference I noticed when disassembling the fork is that the lower fork tube pulled away from the upper fork tube without pulling out the oil seal. On my other bikes and in the YouTube videos, they show that you can remove the oil seal by pulling the two tubes apart. After the lower and upper tubes were separated, it took some effort to pry the seal out.
Another difference is that the bushings in these forks are larger/longer than what I have seen on my other forks. One bushing came out when I drained the oil, while the other one stayed stuck to the upper tube. I believe the bushing that came out was the inner bushing because it seemed to slip into the other bushing very easily when reinstalled. I reinstalled it after I put the spring in during the reassembly process discussed in this thread.
I used a Tusk adjustable seal driver (26mm-45mm), which worked ok for the oil seal but not
on the dust seal. Even though I lubed the dust seal with fork oil, the seal did not want to seat in the upper tube. The Tusk adjustable seal driver did not work well since the brackets that hold the three point of contacts would flex and did not give enough even pressure to drive the seal into place. I ultimately took one half of a larger seal driver (48mm) and use a regular hammer to pound on the driver. Even this was tough since the seal wanted to pop out of the back side while I was trying to drive in the front side. I finally managed to get a good grip on the seal and the seal driver with one hand while hammering with the other. Getting the seal to partially seat and then worked my way around the fork to push the seal in a little bit at a time required dexterity and patience. If I had a video of this procedure, the audio would have been totally censored due to all of the cussing. I am hoping I never have to remove this seal again; it will be a PITA, to be sure.
Be very careful that the lower tube does not fully slide out of the upper tube after you have the seals set. I came close when I was handling the fork before filling with oil. If they do come apart, you will probably a new set of seals,. The seals will most likely be damaged if they are pried off the upper tube, or if you try to push the lower tube back through the seals while they are still seated in the upper tube.
If you forget the sequence of how all the parts (Washers, bushings, spacers…) are installed, a good point of reference is the schematic for the BMW 2016 R1200RS Stanchion. You can google it or click on the link:
Stanchion. 2016 BMW R1200RS | Power BMW Motorcycles, Palm Bay FL
. Just beware it doesn’t explain the reassembly sequence, it just shows a pictorial of the parts and their relative position in the fork tube.
So, after all was said and done, I did not sense any difference in the fork action. My test rides (solo and two up) consisted of surface streets, canyon twisties and freeways, while toggling between road and dynamic settings. I hope this helps. Thanks again to everyone that contributed to this thread.