N-Zeta 501/01, Workshop Manual

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Carburettor Cleaning and Maintenance
On most occasions, carburettor faults are due to impurities entering with the
petrol or air. The time for regular carburettor cleaning will depend on the manner in
which the machine is used. It is not recommended to carry out any carburettor
repairs apart from washing it in clean petrol and setting according to the
maker’s
instructions. Any departure from the basic carburettor setting may be carried out with
a view to the condition of the scooter, its use in varying climatic conditions, or the fuel
used. In these cases, keep within narrow limits keeping a careful check of the fuel
consumption and performance after the differing setting has been carried out.
Other carburettor defects which may occur in operation should be remedied
by repairing or, replacing of its parts. This applies to the throttle valve which, in case
of excessive play in the mixing chamber, should be replaced with a new one or in the
case of seizure should be repaired using fine emery cloth or sharpening stone. One
should never omit, to wash the throttle valve in petrol after it has been repaired, to
remove the fine emery which might cause wear of the mixing chamber.
Another carburettor trouble is its constant flooding. This may be due to a leaky
float or lack of tightness of the float needle / dirt under the needle. To repair the float,
it has to be soldered after drying out or replaced. Lack of tightness of the float needle
in its seat in the float chamber top will be removed by grinding using lapping paste or
by replacing the parts. In case of damage to the throttle valve needle the needle has
to be replaced.