ever been riding along and all of a sudden your speedometer doesn't work any more. check the cable, nope cable is good. check the drive gear on the wheel, nope that's ok too. must be the speedometer. most have a known issue where the grease on the cable shaft heats up in the sun and turns to a hard goop, seizing the shaft and more often than not, destroying the cable. my Huret did and here is how to fix that.
you will need the following tools:
a flat screw driver
an adjustable wrench
a pair of pliers
5mm socket and driver
first you need to remove the speedometer from wherever it mounts. I won't go into that here as there are too many variables. the first 2 pics show mine removed. find a nice quiet workspace somewhere and grab a cold one.
now remove the rubber weather seal in pic 3.