Try this code:

add_action(\'admin_bar_menu\', \'wp_toolbar_custom_menu\', 100);
function wp_toolbar_custom_menu($admin_bar){
    $admin_bar->add_menu( array(
        \'id\'    => \'menu-item\',
        \'title\' => \'Menu Item\',
        \'href\'  => \'#\',
        \'meta\'  => array(
            \'title\' => __(\'Menu Item\'),            
        ),
    ));
}