This page is about the BMW motorcycle models; R50/US, R60/US, R69US, R50/5,
The BMW telescopic forks were introduced in 1968 on the /2 models and were
designated by the suffix "US". When the /5 models came out in 1970, they
had the same forks. One of several problems with them was that of
stiction caused by the bushings. These
bushings are located at the bottom and just up inside of the fork tubes.
They are held in by a snap ring. The old fixed bushings were replaced with
"floating bushings" in 1972. This change solved the stiction problem, from
that source. Other sources, even larger ones, still existed.
Three piece floating bushing
All three pieces
The change is recommended for those forks that may still have the older, one
piece, bushing. The aluminum center piece is trapped by the two outer
threaded pieces, but still allow it to "move or float" around. You can see
it in the middle photograph. The piston rod will not "stick" while moving
up and down.
If your forks are not in nearly perfect alignment, then this change won't
help much. This is the small hole on the dam, plug up the larger ones
first. Go to the excellent article by Randy
Glass on this issue.