When the throttle cable breaks and you don't have a replacement cable or you don't know how to change one. You can still ride your motorcycle using the following tip.
The big screw with a straight slit and spring backing allows idling fuel flow change. Increasing idling fuel revs your engine higher than normal idling rpms.
Use a screw driver or ( index finger and thumb ) and increase the idling fuel flow. This can be achieved by turning the idling fuel flow screw clockwise.
Increase the fuel flow until you can achieve like 20 - 30 kmph speed.
You should be able to ride at safe speed on first few gears to the nearest service point to have a permanent fix.