Recently i have shifted to WordPress Twenty Thirteen Theme. Its an excellent theme with Fully responsive and Retina display. I am going through customization of Twenty Thirteen Theme. Here is a way to disable Search Box in the Nav Menu. I would rather prefer to use Google custom search box in the Sidebar Widget. I will later show you how to add Google custom search box. You can always revert back to search bar in nav menu. See below how:
How To Remove Search Box in Nav Menu
You will need to edit the Header.php file in order to remove the Search box in nav menu. But when you will update the theme, it will be gone. I mean you have to do it again.
How to get back the Search box in Nav Menu?
Just remove the added “//” from that line.
If you happen to know more customization tips, let me know. I am very eager to learn new things specially with The Twenty Thirteen Theme