Short test ride today, on a very bumpy and twisty road. The biggest improvement is to the steering, which is now much quicker and predictable. Bumps were handled nicely, and I even let go of the bars with no wobble. I've just got it set to the base settings. I think I might reduce compression damping a bit. I ride the same road on my 2021 Africa Twin, which is perfect. My GS is closer to that quality now. The big difference is in how the forks flex back and forth. That has been reduced, but it's still there. It will never match the rigidity of the big fat AT forks. But it is much better.
With the forks off the bike, I noticed that the springs were pushing the legs to full extension. They weren't quite reaching that point before.
Some of that improvement might be due to the old forks needing a refurb anyway. But it does feel much better than I can remember it having been in the past, and I've owned it for 23 years and 100,000 miles.
If you are doing a suspension refurb anyway, I recommend this upgrade. It is fairly easy. The hardest parts were:
1. Trying to understand the instructions, then deciding to ignore them - I got a spare fork leg and experimented on that first, so I could work it out.
2. Removing the clip on top of the seals. The seals had worn down, and the clip had corroded into the metal of the leg. It's not a circlip, which seems crazy. I had to buy some hook and pick tools to get them out. The inside of the leg was in a bit of a mess, and I had to dremmel some burring, and fill a small hole. But they are now fine.
This was all done using cheap tools from Amazon.
Hook and pick set.
Fork spring compressor.
Oil level gauge (110mm is the level required)
Circlip pliers
The new seals were driven in by placing the old seals on top of them, followed by a 38mm socket, and knocking that in. They went in straight and complete first time.
The original fork leg bottom bolt is too long for the cartridges, so I used
these shorter bolts.
Also note that the metal gasket that goes below the seals is no longer available from BMW or any of the usual suppliers. I had to reuse the ones that were in there, even though they were a bit mishapen. I did my best to get them back into shape.
I'll post some more details when I get a chance.