I have a 2005 ds650x I shift it to neutral position but the neutral light don't come on and if I squeeze the lever just a bit the light comes on so is it the cable on the gears are not at the right place as I rebuilt the quad from the frame up also rear shock is very stiff what is the best way to make it soft again and yes the spring is at low setting

 

Did you over tighten your shock mounts and swing arm? thats the only thing it can be if it was fine before..