My old R1100RS is just over 44,000 miles old now and I just completed fitting a new speedometer cable. I ordered it the day after (Thursday) the old one broke and the part arrived this morning from Sherlocks. The old cable broke about 30mm from the wheel end.
It is easy enough to fit, turn the key in the ignition to undo the steering lock, and use this to make access to the removal of the two side panels by the dashboard easier. There is a small screw on each side down the opening around the steering – this mounts into the top end of the fuel tank so on my bike one is spinning away the captive screw. The panels have another two long screws at the top of each panel, then they slide out. If you have slim fingers then you can get to the back of the speedo from this stage, but to make it easier I removed the two rubber mounted 10mm bolts either side of the instruments. Note the routing of the existing cable (I forgot one bit) it goes down from the back of the speedometer, goes through a wee hoop on the front mudgard then goes to the drive from the front wheel.
Undo the knurled wheel on the back of the speedometer, and undo the screw holding the clamp at the other end. Fit the new one, putting it through the wee hoop and fitting the splines around the flat drive at the wheel end. Screw the clamp in, and spin the wheel to check the other end turns. In my case it did! Then screw the other end finger tight. I spun the wheel to see if anything would happen, but it didn’t, so I’ll be leaving the proper test to tomorrow when it isn’t as windy.