kpw 50 Workshop-manual : Page 193

          19. EVAPORATIVE/EXHAUST EMISSION
       CONTROL SYSTEM                                                                         K-PIPE 50


    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
                        Prevent exhaust
    Air Injection                                re-burned to reduce CO. When the throttle valve
                        muffler noise and
    Cut-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


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