Got it
add_filter('bp_blogs_activity_new_post_action', 'record_cpt_activity_action', 1, 3);
function record_cpt_activity_action( $activity_action, $post, $post_permalink ) {
global $bp;
if( $post->post_type == 'post' ) {
if ( is_multisite() )
$activity_action = sprintf( __( '%1$s wrote a new article, %2$s, on the site %3$s', 'buddypress' ), bp_core_get_userlink( (int) $post->post_author ), '<a href="' . $post_permalink . '">' . $post->post_title . '</a>', '<a href="' . get_blog_option( $blog_id, 'home' ) . '">' . get_blog_option( $blog_id, 'blogname' ) . '</a>' );
else
$activity_action = sprintf( __( '%1$s wrote a new article, %2$s', 'buddypress' ), bp_core_get_userlink( (int) $post->post_author ), '<a href="' . $post_permalink . '">' . $post->post_title . '</a>' );
}
return $activity_action;
}