Did you notice if the backlight goes out at the same time? Funny thing, for the first time tonight I noticed my (98 Sporty) speedo went to zero, odometer went blank and light was out. After about 5 seconds it all came back on as if I just turned the ignition on (trip meter was still correct). I thought maybe a fuse had gone until it fixed itself....
It may be worth checking if you had the same problem, as it suggests a lack of power rather than the sensor. nothing worse than an intermittent electrical problem.