is good, the cause must be in the wiring used only
by the suspect circuit. If all related circuits are
faulty at the same time, the probable cause is a poor
ground connection or a blown fuse(s).
As with all troubleshooting, analyze typical
symptoms in a systematic manner. Never assume
anything, and do not overlook the obvious, like a
blown fuse or an electrical connector that has sepa-
rated. Test the simplest and most obvious items first
and try to make tests at easily accessible points on
the motorcycle.
The troubleshooting procedures for various elec-
trical systems are listed below. Whenever there is a
problem with the electrical system, perform the
troubleshooting procedures for the affected system.
Start with the first inspection in the list and perform
the indicated check(s). If a test indicates that a com-
ponent is working properly, reconnect the electrical
connections and proceed to the next step. Systemat-
ically work through the troubleshooting checklist
until the problem is found. Repair or replace faulty
parts as described in the appropriate section of the
manual.
Perform these procedures in the listed sequence.
Each test presumes that the components tested in
the earlier steps are working properly. The tests can
yield invalid results if they are performed out of
sequence.
Electrical Component Replacement
Most motorcycle dealerships and parts suppliers
will not accept the return of any electrical part. If
you cannot determine the
exact
cause of any electri-
cal system malfunction, have a Yamaha dealership
retest that specific system to verify your test results.
If you purchase a new electrical component(s), in-
stall it, and then find that the system still does not
work properly, you will probably be unable to
return the unit for a refund.
Consider any test results carefully before replac-
ing a component that tests only
slightly
out of speci-
fication, especially resistance. A number of
variables can affect test results dramatically. These
include: the testing meter’s internal circuitry, ambi-
ent temperature and conditions under which the ma-
chine has been operated. All instructions and
specifications have been checked for accuracy;
however, successful test results depend to a great
degree upon individual accuracy.
Charging System
1. Check the main fuse.
2. Check the battery as described in Chapter Three.
3. Perform the current draw test (Chapter Nine).
4. Perform the charging voltage test (Chapter
Nine).
5. Test the stator coil resistance (Chapter Nine).
6. Check the wiring and connections in the entire
charging system.
7. Replace the voltage regulator/rectifier.
Ignition System
1. Inspect the main fuse and the ignition fuse as de-
scribed in Chapter Nine.
2. Check the battery (Chapter Three).
3. Check the condition of each spark plug (Chapter
Three).
4. Perform the ignition spark test in this chapter.
5. Check the resistance of each spark plug cap
(Chapter Nine).
6. Check the ignition coil resistance (Chapter
Nine).
7. Check the pickup coil resistance (Chapter Nine).
8. Check the continuity of the main switch (Chap-
ter Nine).
9. Check the continuity of the engine stop switch
(Chapter Nine).
10. Check the continuity of the neutral switch
(Chapter Nine).
11. Check the continuity of the sidestand switch
(Chapter Nine).
12. Check the ignition system diode by perform-
ing the
SCCR Diode Test
described in Chapter
Nine.
13. Check the connections in the entire ignition
system.
14. Have a dealership or qualified shop check the
ignitor unit.
Starting System
1. Check the main fuse and the ignition fuse.
2. Check the battery as described in Chapter
Three.
3. Perform the starter operational test (Chapter
Nine).
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CHAPTER TWO
