Truncate RSS-Feed on WordPress-More-Tag

rss-more-tag

// Place in functions.php
function kmb_rss_teaser( $content ){
  $split = preg_split( '#<span id=\"more-\d+\"><\/span>#', $content, 2, PREG_SPLIT_NO_EMPTY );
  if ( count( $split == 2 ) ) {
    $content = balanceTags( $split[0], true );
  }
	return $content;
}
add_filter( 'the_content_feed' ,'kmb_rss_teaser' );
add_filter( 'the_excerpt_rss', 'kmb_rss_teaser' );