Several months ago I wrote an article describing the problem I had with the lower bushing failure on the Fox shock on the R100GS. I previously stated the immediate fix was to replace the bushing with one made of delrin, with a longer term plan of installation of a tierod end spherical bearing. This article reports the results of my efforts.
I installed the delrin bushing prior to the Death Valley trip and eventually put approximately 4,000 miles on it. When I removed the shock to perform the work on the rod end I found virtually no sign of wear on the delrin. I would consider this solution to be adequate for the large majority of users.
As I am planning to keep my GS indefinitely, and plan some rather long and demanding trips, I elected to replace the Fox factory bushing arrangement with a tierod end. After some research and to expedite the process I choose to use an Aurora MM10T (or equivalent) rod end. This was purchased from Motion Engineering in Santa Clara or maybe it's San Jose. The problem with this rod end is that it does not fit the shoulder stud on the rear drive, .625 ID versus 15 mm. I therefore had to fabricate a bushing to adapt to the 15 mm. stud on the rear drive. This bushing is thin walled and required careful machining. I made mine from 304 stainless. I also ensured that the bushing shoulders were sized to fully engage the spherical so the sphere could not rotate. In addition the bushing was sized for a "zero" tolerance fit which required polishing of the stud (performed in place) prior to installation. The installation of the rod end requires cutting off the eye at the lowe! r end, drilling and tapping to accommodate the thread of the rod end. For those interested in additional detail, contact me directly. The change was installed immediately prior to the Reno 200 dual sport which was ridden with no problems.
In summary for all but extreme use I believe the delrin bushing will perform adequately. The correct technical solution is to use a rod end. Not only does it provide for correct operation of the shock on the bike it allows for length adjustment. The only thing I would do differently is to try very hard to find a 15 mm. rod end so the bushing would not be necessary. This installation can technically be performed with the shock assembled, however mine was done when I had the shock disassembled for rebuilding purposes. There may be a safety issue working on the shock while it is pressurized.
As of August, 1997, Fox was performing work on the R100GS shock with a rod end. Also Fox has available a bushing replacement that is of different design that is applicable to: R100GS, R100R, and R80, R100 non paralever models. The preceding published by permission of Brad Hepler.
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