Hover over a number for the key, click on the menu items below to show the vapour/vacuum routings.
Fuel Flow Tank Expansion/Contraction Carb Expansion Crankcase Breathing Anti-runon
Image from Haynes Workshop Manual
Note: On 1978 models a secondary charcoal canister was connected between the anti-runon valve and the air vent pipe.
Any expansion and contraction of fuel or air in the carb float chamber moves through the vapour line (8), charcoal adsorption canister (7), running-on control hose (10), anti-runon valve (9) and the vent pipe (5) to/from the atmosphere. Petrol fumes from the vapours are adsorbed by the charcoal and not discharged to the atmosphere. If the engine is running any fumes from expansion are drawn into the engine and burnt, see Crankcase Breathing.