 In 1963, production of the newly designed "Model 16" started (fitted with either ČZ 175 or Jawa 350 type 572 engines); and the model was modernized again in 1968.In 1971, production of three-wheeled cars stopped, and the company switched to production of a four-wheeler, the "Model 435-0", which featured the Jawa 350 type 572 - 04 engine.Problems in design and manufacturing, as well as the inability to compete with higher-category cars (including the cheap Trabants), made the four-wheeler a commercial failure, and its production was stopped in 1973.