I have a 96 R1100RS with 95k miles on it. I noticed some muck on the fins underneath my sight glass, and thought it may have been starting to weep. So I decided to replace the glass before it got worse.
After draining the oil, I drilled a hole in the window large enough to fit a nail.
I inserted the nail and tried to pry the old sight glass out.
It didn't come out easily, and instead the window broke more.
Not a problem. I took a needle nose pliers and pulled the old seal out.
Here's the empty hole.
Old sight glass with busted glass.
New sight glass. Instead of a red dot in the center, there's a clear dot.
I put the new glass into the opening as far as it would go by hand.
A 1.25" socket fits perfectly as a drift. My rubber mallet came in handy too.
The finished project.
The new glass didn't go in as far as the old one, and didn't seat exactly flush with the surrounding engine case, as the old one did. I put this off to it being a new part number.