Possible Cause
Operation
Incorrect valve sealing or valve adjustment
Inspect the head and/or restore the correct clear-
ance
- Engine flooded.
Try starting-up with the throttle fully open. If the
engine fails to start, remove the spark plug, dry it
and before refitting, make the motor turn so as to
expel the fuel excess taking care to connect the
cap to the spark plug, and this in turn to the ground.
If the fuel tank is empty, refuel and start up.
Automatic starter failure
Check: mechanical movement, electric connec-
tion and fuel supply, replace if required.
Air filter blocked or dirty
Remove the sponge, wash with water and car
shampoo, then soak it in a mixture of 50% petrol
and 50% specific oil. Press with your hand without
squeezing, allow it to drip dry and refit.
Faulty spark plug or incorrect ignition advance
Replace the spark plug or check the ignition circuit
components
The carburettor is dirty; fuel pump or vacuum valve
damaged
Remove, wash with solvent and dry with com-
pressed air or replace
Battery flat
Check the charge of the battery, if there are any
sulphur marks, replace and use the new battery
following the instructions shown in the chapter
Intake coupling cracked or clamps incorrectly
tightened
Replace the intake coupling and check the clamps
are tightened
Defective floating valve
Check the proper sliding of the float and the func-
tioning of the valve
Carburettor nozzles clogged
Dismantle, wash with solvent and dry with com-
pressed air
Excessive oil consumption/Exhaust smoke
EXCESSIVE CONSUMPTION
Possible Cause
Operation
Wrong valve adjustment
Adjust the valve clearance properly
Overheated valves
Remove the head and the valves, grind or replace
the valves
Misshapen/worn valve seats
Replace the head assembly
Worn cylinder, Worn or broken piston rings
Replace the piston cylinder assembly or piston
rings
Worn or broken piston rings or piston rings that
have not been fitted properly
Replace the piston cylinder unit or just the piston
rings
Oil leaks from the couplings or from the gaskets Check and replace the gaskets or restore the cou-
pling seal
Worn valve oil guard
Replace the valve oil guard
Worn valve guides
Check and replace the head unit if required
Insufficient lubrication pressure
POOR LUBRICATION PRESSURE
Possible Cause
Operation
By-Pass remains open
Check the By-Pass and replace if required. Care-
fully clean the By-Pass area.
Vespa GTV 125
Troubleshooting
TROUBL - 3
Summary of Contents for GTV 125
Page 4: ......
Page 6: ......
Page 7: ...INDEX OF TOPICS CHARACTERISTICS CHAR ...
Page 20: ...Characteristics Vespa GTV 125 CHAR 14 ...
Page 21: ...INDEX OF TOPICS TOOLING TOOL ...
Page 34: ...Tooling Vespa GTV 125 TOOL 14 ...
Page 35: ...INDEX OF TOPICS MAINTENANCE MAIN ...
Page 57: ...INDEX OF TOPICS TROUBLESHOOTING TROUBL ...
Page 64: ...Troubleshooting Vespa GTV 125 TROUBL 8 ...
Page 65: ...INDEX OF TOPICS ELECTRICAL SYSTEM ELE SYS ...
Page 89: ... Refit the battery cover Vespa GTV 125 Electrical system ELE SYS 25 ...
Page 90: ...Electrical system Vespa GTV 125 ELE SYS 26 ...
Page 91: ...INDEX OF TOPICS ENGINE FROM VEHICLE ENG VE ...
Page 98: ...Engine from vehicle Vespa GTV 125 ENG VE 8 ...
Page 99: ...INDEX OF TOPICS ENGINE ENG ...
Page 156: ...Engine Vespa GTV 125 ENG 58 ...
Page 167: ... Remove the maximum nozzle Remove diffuser Vespa GTV 125 Engine ENG 69 ...
Page 177: ...INDEX OF TOPICS SUSPENSIONS SUSP ...
Page 199: ...INDEX OF TOPICS BRAKING SYSTEM BRAK SYS ...
Page 215: ...INDEX OF TOPICS COOLING SYSTEM COOL SYS ...
Page 221: ...INDEX OF TOPICS CHASSIS CHAS ...
Page 237: ...INDEX OF TOPICS PRE DELIVERY PRE DE ...
Page 241: ...INDEX OF TOPICS TIME TIME ...