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;
}