My speedo works but when I start to accelerate and get above 20 i start to hear a clicking/winding noise. The faster I go the faster it clicks and the slower I go the slower it clicks. Sound like a cable issue?
If it is still working but making noise, it is very common for the internal lubrication to dry up. You can get a graphite type grease or spray and spray it down one of the ends and work it back and forth to ensure it lubricates the entire cable, and that should quiet it back down for you.