Exhaust Emission Systems: Description

Triumph exhaust emission control is accomplished by engine modifications which improve combustion characteristics, along with special designed carburetors and ignition distributors. Carburetor modifications include a biased type spring loaded needle, temperature compensation for mixture and a throttle by-pass valve. All models incorporate "lost motion" accelerator linkage for improved low speed engine operation. Stag models also incorporate a thermostatically controlled air cleaner. All ignition distributors are equipped with mechanical advance. Depending on year model, engine, and fuel system, distributors also have either vacuum advance and/or vacuum retard systems. All late models use a thermostatic vacuum switch to prevent engine overheating by allowing normal ignition advance at high engine temperatures.