I have just got a hyosung gtr 250 and my digital speedo is not working

The digital speedo works off of a couple sensors that I would have to do research to find. To begin with start by testing with a mutil meter at the plug at the speedo to see if you are getting power. That would elimate all sensors, then if you are not getting power you would know it is electrical and not a sensor. If you get power then It would indicate that a sensor is gone out, most likely the speed sensor. If you dont have power you will need to first check the fuse that controls that circuit, if it is good then all you can do is follow the wires to the problem by checking the OHMs from one section to the next until you find the breakdown.