PIAGGIO MSS ZIP 100 4T, Service Manual

Page: 40 / 192

Possible Cause Operation
Air filter blocked or dirty. Dismantle the sponge, wash with water and shampoo, then
soak it in a mixture of 50% petrol and 50% of specific oil (Se-
lenia Air Filter Oil), then hand dry without squeezing, allow to
drip dry and then reassemble.
Defective floating valve Check the proper sliding of the float and the functioning of the
valve
Rear wheel spins at idle
REAR WHEEL
Possible Cause Operation
Idling rpm too high Check the idling speed and, if necessary, adjust the C.O.
Clutch fault Check the spring/friction mass and the clutch bell
Air filter housing not sealed Correctly refit the filter housing and replace it if it is damaged
Purifier-carburettor fitting damaged Replace
Starting difficulties
DIFFICULTY STARTING UP
Possible Cause Operation
Defective spark plug or with incorrect electrode gap Check and if necessary replace the spark plug and the elec-
trode gap
Battery flat Check the state of the battery. If it shows signs of sulphation
replace it and bring the new battery into service charging it for
eight hours at a current of 1/10 of the capacity of the battery
itself
- Engine flooded. Start the vehicle keeping the throttle fully open alternately mak-
ing the engine run for approx. five seconds and stopping for
other five seconds. If however it does not start, remove the
spark plug, the engine over with the throttle open being careful
to keep the cap in contact with the spark plug and the spark
plug grounded but away from its hole. Refit a dry spark plug
and start the vehicle.
Vacuum operated cock failure Check that fuel is adequately supplied through the pipe by ap-
plying a vacuum on the suction pipe
Failing automatic starter on the carburettor Check the electrical wiring and mechanical movement, replace
if necessary.
Wrong ignition advance Check flywheel keying on the crankshaft, replace control unit if
necessary
Incorrect valve sealing or valve adjustment Remove the head and the valves, grind the seats, descale the
valve heads and, if necessary, replace any faulty part. check
and restore the correct valve clearance.
Start-up rpm too low or starter motor failure Check starter motor
Altered fuel characteristics Drain off the fuel no longer up to standard; then, refill
Carburettor nozzles clogged or dirty Dismantle, wash with solvent and dry with compressed air
Excessive oil consumption/Exhaust smoke
RICH OR GREASY MIX
Possible Cause Operation
Air calibrated holes in carburettor blocked Dismantle, wash with solvent and dry with compressed air
Defective floating valve Check the proper sliding of the float and the functioning of the
valve
Level in chamber too high Restore the correct level in the chamber (the float must be par-
allel to the upper cover contact plane, that is the throttle valve
membrane cover)
The starter remains on Check that the automatic starter works and moves correctly
and it is properly powered.
Troubleshooting
MSS ZIP 100 4T
TROUBL - 40