Hinge won't start turning until I manually switch it off and on again

Hi, I create a hinge joint via instantiate, and then set it's motor settings to some values. Still it's not turning, despite having the right settings in the inspector during runtime. If I change any value of the hinge in the inspector, it will instantly start to work. I tried waking the according rigidbody and it did nothing. This is kind of a game breaking bug, which I really need to fix. Any ideas ?