Insufficient Lubrication Pressure - VESPA GTV 125 Service Station Manual

Vespa GTV 125
Possible Cause
Incorrect valve sealing or valve adjustment
- Engine flooded.
Automatic starter failure
Air filter blocked or dirty
Faulty spark plug or incorrect ignition advance
The carburettor is dirty; fuel pump or vacuum valve
damaged
Battery flat
Intake coupling cracked or clamps incorrectly
tightened
Defective floating valve
Carburettor nozzles clogged
Excessive oil consumption/Exhaust smoke
Possible Cause
Wrong valve adjustment
Overheated valves
Misshapen/worn valve seats
Worn cylinder, Worn or broken piston rings
Worn or broken piston rings or piston rings that
have not been fitted properly
Oil leaks from the couplings or from the gaskets Check and replace the gaskets or restore the cou-
Worn valve oil guard
Worn valve guides

Insufficient lubrication pressure

Possible Cause
By-Pass remains open
Inspect the head and/or restore the correct clear-
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.
Check: mechanical movement, electric connec-
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
Replace the spark plug or check the ignition circuit
Remove, wash with solvent and dry with com-
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
Replace the intake coupling and check the clamps
Check the proper sliding of the float and the func-
Dismantle, wash with solvent and dry with com-
EXCESSIVE CONSUMPTION
Remove the head and the valves, grind or replace
Replace the piston cylinder assembly or piston
Replace the piston cylinder unit or just the piston
POOR LUBRICATION PRESSURE
Check the By-Pass and replace if required. Care-
Operation
ance
tion and fuel supply, replace if required.
squeezing, allow it to drip dry and refit.
components
pressed air or replace
are tightened
tioning of the valve
pressed air
Operation
Adjust the valve clearance properly
the valves
Replace the head assembly
rings
rings
pling seal
Replace the valve oil guard
Check and replace the head unit if required
Operation
fully clean the By-Pass area.
Troubleshooting
TROUBL - 3