When 1974 came, engines were still not being delivered in sufficient numbers, although some started to arrive early that year. At that point, unexpectedly, Hirth went bankrupt after about 500 engines had shipped. Once again, the BD-5 lacked a suitable engine, but this time the search for a replacement ended with a Zenoah design from Japan. Development of this engine was lengthy, and in the end it would not be certified for export until 1978, although this was not anticipated at the time.