Update Wheels with Wheels collider

Hello. I am making my first game for me…
I try make motorbike so i use Wheel Collider for move.
I made motorbike in Blender and then import to Unity. When I activate script and when I press W, Motorbike go backward and when i press S motorbike go forward WHY ?..
And Wheels meshes are bad I do not know why.

I try use motorbike from Asset Store. Motorbike from AssetStore worked very well.
So What is the problem ?

Sorry for bad english I am not from England or America.
Image of problem :
http://postimg.org/image/8v7hsixez/

  /////////////////This is a code of Wheels update chceck ///////////////
F is wheel collider of front wheel and R is wheel collider of Rear wheel TireF and TireR are Wheels
void Front() {
        for (int i = 0; i < 2; i++)
        {
            Quaternion quat;
            Vector3 pos;
            F.GetWorldPose(out pos, out quat);

            TireF[0].position = pos;
            TireF[0].rotation = quat;
        }
    }

    void Rear()
    {
        for (int i = 0; i < 2; i++)
        {
            Quaternion quat;
            Vector3 pos;
            R.GetWorldPose(out pos, out quat);

            TireR[0].position = pos;
            TireR[0].rotation = quat;
        }
    }

The pivots for your mesh are likely wrong.

Pivots on wheels mesh ?