Honda Transalp XL700V Manual page 61

GENERAL INFORMATION
EXHAUST EMISSION CONTROL SYSTEM
The exhaust emission control system is composed of a pulse secondary air supply system, a three-way catalytic converter
and PGM-FI system.
No adjustment should be made about the exhaust emission control systems. The exhaust emission control system is
separate from the crankcase emission control system.
SECONDARY AIR SUPPLY 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 PAIR (Pulse Secondary Air Injection) control valve.
This charge of fresh air promotes burning of the unburned exhaust gases and changes a considerable amount of
hydrocarbons and carbon monoxide into relatively harmless carbon dioxide and water vapor.
The reed valve prevents reverse air flow through the system. The PAIR control valve is operated by the solenoid valve. The
solenoid valve is controlled by the PGM-FI unit, and the fresh air passage is opened/closed according 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.
PAIR CHECK VALVE
EXHAUST PORT
1-56
AIR CLEANER HOUSING
PAIR CONTROL VALVE
FRESH AIR
EXHAUST GAS