Exhaust Emission Control System (Pulse Secondary Air Injection System) - Honda GL1800 Service Manual

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GENERAL INFORMATION

EXHAUST EMISSION CONTROL SYSTEM (PULSE SECONDARY AIR INJECTION SYSTEM)

The exhaust emission system is composed of a lean fuel injection setting and a secondary air supply system, no adjust-

ments should be made except idle speed adjustment with the throttle stop screw. The exhaust emission control system is

separate from the crankcase emission control system.

The secondary air supply system introduces filtered air into the exhaust gases in the exhaust port. Fresh air is drawn into

the exhaust port by the function of the Pulse Secondary Air Injection (PAIR) control valve.

This charge of fresh air promotes burning of the unburned exhaust gases and changes a considerable amount of hydrocar-

bons and carbon monoxide into relatively harmless carbon dioxide and water vapor.

The reed valve prevents reverse air flow through the system. The PAIR solenoid control valve is controlled by the PGM-FI

unit, and the fresh air passage is opened and closed according to the running condition (ECT/IAT/TP/MAP sensor and

engine revolution).

No adjustments to the secondary air supply system should be made, although periodic inspection of the components is

recommended.

P IR CONTROL SOLENOID V LVE

P IR CHECK V LVE

EXH UST PORT