BuddyPress.org

You have to remove the action after it’s defined by bp. Which is after bp loads up. In bp-custom.php:

function replace_bp_core_action_search_site(){

remove_action( ‘init’, ‘bp_core_action_search_site’, 5 );

add_action( ‘init’, ‘YOUR_bp_core_action_search_site’, 5 );

}

add_action(‘plugins_loaded’, ‘replace_bp_core_action_search_site’);