Ignition Ht Coils - Check, Removal And Installation - Yamaha TDM850 User Manual

UNREGISTERED VI
3.4a Ignition coil - 1991 to 1995 TDM
models
repeat the test for the other coil. If the test results
are good the entire ignition system can be
considered good. If the spark appears thin or
yellowish, or is non-existent, further investigation
will be necessary. 6 Ignition faults can be divided
into two categories, namely those where the
ignition system has failed completely, and those
which are due to a partial failure. The likely faults
are listed below, starting with the most probable
source of failure. Work
systematically, referring
sections for full details of the necessary checks
and tests. Note: Before checking the following
items ensure that the battery is fully charged and
that all fuses are in good condition.
a) Loose, corroded or damaged wiring
connections, broken or shorted wiring
-
p^\
I
3.6 To test the coil primary resistance, connect the multimeter leads between the
3.7a Coil secondary resistance test -1991 to 1995 TDM and all XTZ models
UNREGISTERED VI
3.4b Ignition coil - TRX models
between any of the component parts of the
ignition system (see Chapter 9).
b) Faulty HT lead or spark plug cap, faulty
sparkplug, dirty, worn or corroded plug
electrodes, or incorrect gap between
electrodes.
c) Faulty ignition (main) switch or engine kill
switch (see Chapter 9).
d) Faulty neutral, clutch or sidestand switch,
through the list
and on XTZ models, diode (see Chapter 9).
to the subsequent
e) Faulty pick-up coil or damaged rotor triggers.
f) Faulty ignition HT coilfs).
g) Faulty ignitor unit.
7 If the above checks don't reveal the cause of
the problem, have the ignition system tested by a
Yamaha dealer equipped with diagnostic testing
equipment.
primary circuit terminals on the coil
QX1
I
UNREGISTERED VI
Ignition system 5»3
3.4c Ignition coil - XTZ models
3 Ignition HT coils - check,
removal and installation
Check
1 The ignition HT coil(s) can be checked visually
(for cracks and other damage) and the primary
and secondary coil resistance can be measured
with a multimeter. If the coil is undamaged, and if
the resistance readings are as specified at the
beginning of the Chapter, it is probably capable of
proper operation, although note that sometimes a
fault is only evident when the coil is under load
and the engine running at high speed.
2 Remove the left-hand side cover (XTZ models)
or the seat (all other models) (see Chapter 8).
3 Disconnect the battery negative (-ve) lead.
4 On TDM and TRX models, the coil(s) is/are
mounted on the inside of the frame behind the
steering head - remove the fuel tank and the air
filter housing for access (see Chapter 4) (see
illustrations). On XTZ models, the coil is
mounted underneath the rear of the fuel tank -
remove the tank for access (see Chapter 4) (see
illustration).
5 Disconnect the primary circuit
connectors from the coil and the HT leads from
the spark plugs. Mark the locations of all wires
and leads before disconnecting them.
6 Set the meter to the ohms x 1 scale and
measure the resistance between the primary
circuit terminals on the coil (see illustration).
This will give a resistance reading of the primary
windings of the coil and should be consistent with
the value given in the Specifications at the
beginning of the Chapter.
7 To check the condition of the secondary
windings, unscrew the spark plug caps from the
HT leads and set the meter to the K ohm scale.
On 1991 to 1995 TDM models and XTZ models,
connect one meter probe to one HT lead end and
the other probe to the other HT lead end (see
illustration). On 1996-on TDM models and TRX
models, connect the positive (+ve) meter probe
to the HT lead end and the negative (-ve) probe
to the red/black wire
UNREGISTERED VI
I
electrical
Staged by Stalker