Hello Mojobaby
First apologize for my late response.
The last time i removed the speedo cable i didn´t saw any rubber o-ring... Maybe that´s the problem. By the way, the rubber it´s between the nylon bush and the speedo? I talked with the older owner of my r4, a mechanic, who gave me a six month warranty of the vehicle, and he will substitute the speedo, in any case i will check it first and try to find more information about the rubber o-ring, do you have any photo? The last time i checked the speedo with a drill, to confirm that´s not breaked it was anti-clockwise if my memory don´t trick, but you can try in both ways, very slow velocity
Thanks a lot.