Problem with wheeljoint2d motor: nothing happens when changing speed

For some reason I'm unable to adjust the "motor" value of a wheeljoint2D.

Code (csharp):

1.  
2. public JointMotor2D motor;
3.  
4. //...
5. void Start() {
6. this.motor = this.gameObject.GetComponent<WheelJoint2D>().motor;
7. }
8.  
9.     void Update() {
10.         this.motor.motorSpeed = -1000f;  
11.        Debug.Log(this.motor.motorSpeed); // this will print "-1000f" but nothing happens
12.      
13.     }
14.  

The above code prints "-1000f" just fine, but in the inspector the motor speed remains 0.

If I adjust the motor speed in inspector, the wheel starts rotating just fine.

Any idea what could be wrong? (Using unit y4.6.1f1)

 

Okay, I got it sorted out. What a strange thing After "getting motor" I must adjust values and "set motor back to wheeljoint".

So, here's examples:

Code (csharp):

1.  
2. // this is the basic setup...
3.     public WheelJoint2D wheeljointFront;
4.     public JointMotor2D motorFront;
5.  

this one does NOT work:

Code (csharp):

1.  
2. //this doesn't work
3.         this.motorFront = this.wheeljointFront.motor;
4.         this.motorFront.motorSpeed = -1000f;  
5.  

here the thing that works:

Code (csharp):

1.  
2.         this.motorFront = this.wheeljointFront.motor;
3.         this.motorFront.motorSpeed = -1000f;  
4.         this.wheeljointFront.motor = this.motorFront;
5.