The 2 stroke was made by Komatsu under an agreement with Briggs, beginning in 1987. The venture was uneconomic and didn't persist for very long, so the engines are moderately uncommon but not rare. It does seem to be regarded as a decent engine, comparable for example with the Suzuki and Kawasaki 2 stroke mower engines. If you link "Komatsu Zenoah" with Briggs when you search, you should find more information.