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Fuel and exhaust systems 4.5
6 Air filter housing
-
removal and installation
Removal
1 Remove the cover from the air filter housing
and remove the filter element (see Chapter 1).
2 Unscrew the bolts securing the air filter
housing to the transmission casing and
manoeuvre the housing away, noting how it
fits (see illustrations).
3 Unscrew the bolt securing the air intake
duct to the transmission casing and remove
the duct (see illustrations).
lnstallation
4 Installation is the reverse of removal.
Ensure the filter housing is a firm fit over the
carburettor intake.
7 Choke mechanism
-
check
1 Poor starting or poor engine performance
and an increase in fuel consumption are
possible signs that the automatic choke
mechanism is not working properly.
2 The resistance of the automatic choke unit
should be checked with a multimeter when
the engine is cold. Remove the storage
compartment (see Chapter 7) and trace the
wiring from the automatic choke unit on the
carburettor and disconnect
it at the
connectors (see illustrations).
3 Measure the resistance between the
terminals on the choke unit side of the
connector with the multimeter set to the ohms
x 1 scale. If the result is not as specified at the
beginning of this Chapter, the choke unit is
probably faulty. Renew the choke unit (see
Section 10).
4 On 1996 to 2003 models, if the automatic
choke unit appears to be functioning
correctly, check the resistance in the choke
resistor (see illustration). Remove the
headlight
panel (see Chapter 7) and
disconnect the resistor wiring connector (see
Wiring Diagrams, Chapter 9). Measure the
7.2a Trace the wiring from the automatic
choke unit..
.
6.2a Fixings for air filter housing on
Speedfight
6.3a Fixing for air intake duct on
Speedfight
resistance between the terminal on the
resistor side of the connector and earth
(ground). If the result is not as specified at the
beginning of this Chapter, the resistor is
probably faulty.
8 Carburettor overhaul
-
general information
1 Poor engine performance, hesitation, hard
starting, stalling, flooding and backfiring are
all signs that major carburettor maintenance
may be required.
2 K e e p in mind that many so-called
carburettor
problems
are
really
not
carburettor problems at all, but mechanical
problems within the engine or ignition system
malfunctions. Try to establish for certain that
the carburettor is in need of maintenance
6.2b Fixing for air filter housing on Trekker
and Vivacity
6.3b Fixing for air intake duct on Trekker
and Vivacity
before beginning a major overhaul.
3 Check the fuel tap and filter, the fuel and
vacuum hoses, the air filter, the ignition
system and the spark plug before assuming
that a carburettor overhaul is required.
4 Most carburettor problems are caused by
dirt particles, varnish and other deposits
which build up in and block the fuel and air
passages. Also, in time, gaskets and O-rings
shrink or deteriorate and cause fuel and air
leaks which lead to poor performance.
5 When
overhauling
the
carburettor,
disassemble it completely and clean the parts
thoroughly with a carburettor cleaning
solvent,
then
dry
them
with
filtered
compressed air. Blow through the fuel and air
passages with compressed air to force out
any dirt that may have been loosened but not
removed by the solvent. Once the cleaning
process
is complete,
reassemble the
carburettor using new gaskets and O-rings.
7.2b
. . .
and disconnect it at the
connectors
7.4 Choke resistor is mounted behind the
front panel
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