1979 KZ650b3

I have one for you guys to ponder. I could use some ideas! Just finished complete restoration on a 1979 KZ650-B3. I have one last thing that is driving me nuts! The speedometer. Installed new speedo cable and the speedo will not register. The lower end is engaged properly. When I unhook from speedo, the cable turns when I spin the wheel. Hook back up and it will not operate the speedo. Unhook at the wheel and spin cable with my fingers and speedo works fine. The cable is long enough because I can pull it out of the speedo until there is only 1/8" into the speedo, spin cable with finger and speedo works fine. Hook both ends back up and will not work. Poultergeist? Any help would be greatly appreciated.

Could you have reversed the wheel so that the speedo drive is on the right side? That would turn the speedo the wrong way, and there is a pin to prevent it from showing it.

Thanks faffi. The wheel is on in the proper position.

Does the cable rotated by the wheel turn the same direction as you do with your fingers? If so, try hooking it up to the tacho and see of that moves or not. Also, you can hook the tacho cable to the speedo and see if it works.