[Moybin]

If the self-cancel works the same as it did on my K100 it essentially 'counts' the speedo pulses to figure out when to cancel.

I would look to see if you have a problem at the other end, electrically speaking. Perhaps the sensor that feed the speedometer circuitry with pulses is not reading properly. I think this is a proximity switch that reads the teeth on the hypoid gear in the rear end (more knowledgable members please blast me if I am wrong).

I work with proximity switches all the time. They have a gap or clearance tolerance which is quite small, usually only a 3 to 10 mm maximum. If your sensor has backed out, it might not be reading the teeth and generating a signal. Thus no speedo output.