Yamaha TDM850 User Manual page 121

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5*6 Ignition system
7.3 Throttle position sensor wiring connector (A) and mounting
Check
3 Remove the fuel tank and the air filter housing
(see Chapter 4). The throttle sensor is mounted
on the outside of the left-hand carburettor (see
illustration).
4 Make sure that the ignition is OFF, then
disconnect the throttle sensor's wire connector.
Using a multimeter set on the K-ohms range,
measure the resistance between the blue and
black/blue wire terminals on the throttle sensor
half of the connector; 3.5 to 6.5 K-ohms should
be shown (see illustration). Now measure the
resistance between the yellow and black/blue
wire terminals on the same half of the connector;
whilst rotating the throttle grip slowly the
resistance should vary between 0 to 5 K-ohms ±
1.5 K-ohm. If either test does not produce the
correct readings the throttle sensor should be
renewed.
5 If the fault cannot be traced to the throttle
sensor, check all three wires between the ignitor
and throttle sensor for continuity. Check for
continuity between one end to the
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screws (B)
other on each wire. If no continuity is indicated,
this is probably due to a damaged or broken wire
between the connectors; pinched or broken wires
can usually be repaired. If the wiring and
connectors are good, check the adjustment of
the sensor as described below.
6 If the sensor is suspected of being faulty,
take it to a Yamaha dealer for further testing. If
it is confirmed to be faulty, it must be
renewed; the sensor is a sealed unit and
cannot therefore be repaired. If the sensor is
good, have the ignitor checked by the dealer.
Adjustment
7 Before adjusting the sensor, check the idle
speed and carburettor synchronisation (see
Chapter 1).
8 Turn the ignition switch ON, then disconnect
and reconnect the sensor wiring connector. This
sets the ignitor unit to sensor adjustment mode.
9 Slacken the sensor mounting screws and
rotate the sensor until the tachometer needle
7.4 Throttle position sensor wiring connector terminals
Bit Black and blue
Y Yellow
reads 4000 rpm. If the tachometer reads either
1000 rpm or 8000 rpm, the angle of the sensor is
either too narrow or too wide. Adjust it as
required until the reading is 4000 rpm, then
tighten the screws.
10 To come out of the adjustment mode,
start the engine or simply turn the ignition
switch OFF.
Replacement
11 Remove the carburettors (see Chapter 4).
12 The throttle sensor is mounted on the outside
of the left-hand carburettor (see illustration 7.3).
Disconnect the wiring connector, then unscrew
the sensor mounting screws and remove the
sensor, noting how it fits. Retrieve the seal from
behind the sensor as it is withdrawn. On TRX
models and 1991 to 1998 TDM models the
sensor mounts on a plate which is itself secured
to the carburettor body by two screws.
13 Install the sensor and lightly tighten the
screws. After installing the carburettors follow the
adjustment procedure above to set the correct
sensor position.
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L Blue
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