agility city 125 Workshop-manual : Page 23

          1. GENERAL INFORMATION                                                            AGILITY CITY 125

 ENGINE LACKS POWER

 Inspection/Adjustment                                Symptom                          Probable Cause
 Start engine and accelerate
 lightly for observation                                                            Clogged air cleaner
                                                                                    Poor quality fuel (Restricted)
                                                                                    Clogged fuel tank cap breather hole
                                    Engine speed          Engine speed does not     Clogged exhaust muffler
                                    increases             increase sufficiently     Faulty auto bystarter
                                                                                    Split carburetor vacuum piston
 Check ignition timing                                                              diaphragm
 using a timing light                                                               Faulty auto fuel valve
                                                                                    Faulty CDI unit
                                    Correct timing          Incorrect timing        Faulty pulser coil

 Check valve clearance
                                                                                    Improper valve clearance
                                        Correct                 Incorrect           adjustment
                                                                                    Worn valve seat (valve stem too
                                                                                    protruding
 Test cylinder compression
                                                                                    Improper valve and seat contact
                                     Normal                  Abnormal               Worn cylinder and piston rings
                                     compression             compression            Leaking cylinder head gasket
                                                                                    Improper valve timing
 Check carburetor for
 clogging

                                     Not clogged                Clogged             Clogged carburetor jets

 Remove spark plug and
 inspect

                                  Plug not fouled or         Plug fouled or         Fouled spark plug
                                  discolored                 discolored             Incorrect heat range plug
 Remove oil dipstick and
 check oil level and condition
                                                             Incorrect or           Oil level too high
                                    Correct and not                                 Oil level too low
                                    contaminated             contaminated
                                                                                    Oil not changed
 Remove cylinder head oil
 pipe bolt and inspect
                                                          Valve train not           Clogged oil pipe
                                 Valve train lubricated
                                 properly                 lubricated properly       Faulty oil pump

 Check if engine overheats
                                                                                    Worn cylinder and piston rings
                                                                                    Mixture too lean
                                    Engine does not         Engine overheats        Poor quality fuel
                                    overheats                                       Excessive carbon buildup in
                                                                                    combustion chamber
                                                                                    Ignition timing too early
 Rapidly accelerate or run
 at high speed
                                                                                    Excessive carbon build-up in
                                                                                    combustion chamber
                                 Engine does not knock       Engine knocks          Poor quality fuel
                                                                                    Clutch slipping
                                                                                    Mixture too lean
                                                                                    Ignition timing too early



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