Kymco MO D200 Service Manual - chap 20 (imp scarico)

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20. EXHAUST EMISSION CONTROL
SYSTEM
20-0
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20
EXHAUST EMISSION CONTROL SYSTEM
SCHEMATIC DRAWING ............................................................ 20-1
EXHAUST EMISSION CONTROL SYSTEM FUNCTION............. 20-1
TROUBLESHOOTING ................................................................ 20-2
SERVICE INFORMATION .......................................................... 20-2
SECONDARY AIR CLEANER..................................................... 20-3
AIR INJECTION CUT-OFF VALVE (A.I.C.V.)............................. 20-3
REED VALVE ............................................................................ 20-4
20
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20. EXHAUST EMISSION CONTROL
SYSTEM
20-1
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SCHEMATIC DRAWING
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
Secondary Air Cleaner
Filter secondary air.
It filters the fresh air drawn for re-burning to prevent dirt or dust from affecting the operation of the air injection cut-off valve.
Air Injection Cut­off Valve
Prevent exhaust muffler noise and backfiring at sudden deceleration.
The air injection cut-off valve usually opens to lead air into the exhaust muffler in which air is re­burned to reduce CO. When the throttle valve closes suddenly, the air injection cut-off valve is actuated by vacuum to close and cut off secondary air in order to prevent exhaust muffler backfiring due to air in the exhaust system.
Reed Valve
Control the secondary air inlet to reduce CO.
When the motorcycle speed is less than 50km per hour, the reed valve operates to draw secondary air into the exhaust system for re-combustion.
Secondary Air Cleaner
Carburetor
Reed Valve
Air Injection Cut-off Valve
Vacuum
Secondary Air Cleaner Into Hole
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20. EXHAUST EMISSION CONTROL
SYSTEM
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TROUBLESHOOTING
High CO at idle speed
1. Damaged or clogged reed valve
2. Damaged or clogged air injection cut-off valve
3. Clogged air cleaner
Backfiring at sudden deceleration
1. Damaged reed valve (malfunction)
2. Faulty air injection cut-off valve (unable to close)
3. Carburetor incorrectly adjusted
4. Faulty air cut-off valve
5. Leaking vacuum tube
Exhaust muffler noise
1. Faulty air injection cut-off valve
2. Broken vacuum tube
3. Faulty reed valve
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
Vacuum pump
SPECIFICATIONS
Air injection cut-off valve actuating pressure 250mm/Hg30 liter/min. Reed valve stopper clearance4.6mm
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20. EXHAUST EMISSION CONTROL
SYSTEM
20-3
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SECONDARY AIR CLEANER / AIR INJECTION CUT-OFF VALVE (A.I.C.V.)
REMOVAL
Remove the seat. (2-4) Remove the body cover. Disconnect the secondary air cleaner /(A.I.C.V) connecting tube.
INSPECTION
Inspect the air injection cut-off valve flow using a vacuum pump. If the flow is not within the specified values, replace with a new one. The flow should be at least 30 liter/min when a vacuum of 250mm/Hg is applied. The flow should be at least 1.6 liter/min when a vacuum of 320mm/Hg is applied. Check each connecting tube for cracks or damage and replace if necessary.
INSTALLATION
The installation sequence is the reverse of removal.
The secondary air cleaner must be
assembled and installed properly to avoid dust entering the air cleaner.
When installing, be careful not to
bend or twist the tubes and check for proper installation.
The tube length is very important to
its performance, use the tube of same specification for replacement.
Air Inlet Tube
Bolt
Secondary Air Cleaner / A.I.C.V.
Air Outlet Tube
Air Inlet Tube
Air Outlet Tube
Bolt
Vacuum Tube
Bolt
Vacuum Tube
Bolt
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20. EXHAUST EMISSION CONTROL
SYSTEM
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REED VALVE
REMOVAL
Remove the frame center cover. Remove the floor board cover. Disconnect the secondary air inlet tube connector. Remove the reed valve cover three bolts and two secondary air outlet tube bolts.
Remove the three bolts attaching the reed valve cover and the reed valve.
INSPECTION
Check the reed valve for cracks, damage, big clearance or weak reeds. Replace if necessary. Check the gasket and O-ring for damage or deterioration and replace if necessary. Reed valve stopper clearance: 4.6mm
INSTALLATION
Install the reed valve in the reverse order of removal.
Cylinder Head Cover
Bolt
Secondary Air Inlet Tube Bolt
Reed Valve
Reed Stopper
Reed Valve Cover
Bolt
When installing, be careful not to bend
or twist the tubes and check for proper installation.
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