How to increase Bootstrap Modal Width?

The easiest way can be inline style on modal-dialog div :

<div class="modal" id="myModal">
   <div class="modal-dialog" style="width:1250px;">
      <div class="modal-content">
            ...

        </div>
     </div>
 </div>

In your code, for the modal-dialog div, add another class, modal-lg:

<div class="modal-dialog modal-lg">

Or if you wanna centre your modal dialog, use:

.modal-ku {
  width: 750px;
  margin: auto;
}