Motor vehicles equipped with compression ignition (diesel) engines:
(a) Exhaust gas opacity to be measured during free acceleration (no load from idle up to cut-off speed) with gear lever in neutral and clutch engaged.
... in Section XVI, Chapter 84 and in particular in heading No 84.63, "transmission shafts, cranks, bearing housings, plain-shaft bearings, gears and gearing (including friction gears and gear-boxes and other variable speed gears), flywheels, pulleys and pulley blocks, clutches and shaft couplings" ...
