18. EVAPORATIVE/EXHAUST EMISSION
CONTROL SYSTEM
EXHAUST EMISSION CONTROL SYSTEM
The exhaust emission control system adopted in this model utilizes the reed valve to draw
secondary air into the exhaust system for re-combustion by means of exhaust pulsation so as to
minimize the exhaust emission.
FUNCTION
Item Purpose Function
It filters the fresh air drawn for re-burning to
Secondary Air Filter secondary air. prevent dirt or dust from affecting the operation of
Cleaner the air injection cut-off valve.
The air injection cut-off valve usually opens to
lead air into the exhaust muffler in which air is re-
Prevent exhaust
Air Injection Cut- muffler noise and burned to reduce CO. When the throttle valve
off Valve closes suddenly, the air injection cut-off valve is
backfiring at sudden actuated by vacuum to close and cut off secondary
deceleration. air in order to prevent exhaust muffler backfiring
due to air in the exhaust system.
Control the secondary Whenthe reed valve operatesis less than 50km per
the motorcycle speed
Reed Valve hour, to draw secondary air
air inlet to reduce CO. into the exhaust system for re-combustion.
SERVICE INFORMATION
GENERAL INSTRUCTIONS
· During operation, be careful to avoid scalding caused by the exhaust muffler.
· Note the locations of tubes for proper installation.
· Replace any damaged tube with a new one.
· Make sure to tighten the connector of each tube securely
TOOLS SPECIFICATIONS
· Vacuum pump Air injection cut-off valve actuating pressure
250mm/Hg30 liter/min.
Reed valve stopper clearance6.6mm
TROUBLESHOOTING
High CO at idle speed Exhaust muffler noise
· Damaged or clogged reed valve · Faulty air injection cut-off valve
· Damaged or clogged air injection cut-off valve · Broken vacuum tube
· Clogged air cleaner · Faulty reed valve
Backfiring at sudden deceleration
· Damaged reed valve (malfunction)
· Faulty air injection cut-off valve (unable to close)
· Carburetor incorrectly adjusted
· Faulty air cut-off valve
· Leaking vacuum tube
18-1