ISO 789-4:1986

This second edition cancals and replaces the first edition (1982). This part is the fourth of a series of eight. Specifies a method of measuring the smoke emiited by the engines of tractors operating at a steady speed. Annex A gives characteristics of opacimeters; installation and use of theopacimeter is described in annex B; annex C tabulates reference fuel specifications; annex D includes an specimen test report.