Honda Goldwing Motorcycle Electrical Systems

Honda Goldwing Motorcycle Electrical Systems
,
MOTORCYCLE
ELECTRICAL
SYSTEMS
)
HONCA TECHNICAL SE:=2IES
Published by AMERICAN HONDA MOTOR CO.• INC.; MOTORCYCLE & POWER PRODUCTS SERVICE DEPARTMENT
EQUIPMENT AND PROCEDURES SHOWN IN THIS MANUAL APPLY TO HONDA MOTORCYCLES AVAILABLE AS OF JULY, 1977.
HONDA MOTORCYCLE MODELS FOR 1978 INTRODUCE SOME NEW OR MODIFIED EQUIPMENT AND PROCEDURES THAT ARE
NOTCOVEAED IN THIS MANUAL
C Am,riun Honda MOto, Co.
Inc. 1977
FOREWORD
This manual is designed to provide motorcycle owners, students, and mechanics with a complete understanding of the construction and operating principles of motorcycle electrical systems. A troubleshooting
chart is included for the diagnosis and correction of electrical problems.
The manual starts with a simplified description of the basic principles. Subsequent sections describe specific
electrical system circuitry, adding technical detail as the reader's comprehension grows.
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Special care has been exercised in preparing clear, simple illustrations as an aid in visualizing the complex
electrical systems described in the text.
The variety of electrical equipment in use, and frequent design changes, preclude the listing of service specifications. Refer to the factory shop manual for service information on specific electrical components.
Equipment and procedures shown in this manual apply to Honda motorcycles available as of July, 1977.
Honda motorcycle models for 1978 introduce some new or modified equipment and procedures that are
not covered in this manual.
AMERICAN HONDA MOTOR CO .. INC.
•
MOTORCYCLE & POWER PRODUCTS SERVICE DEPARTMENT
•
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TABLE OF CONTENTS
PAGE
SUBJECT
BASIC PRINCIPLES OF ELECTRICITY AND MAGNETiSM ......•...........•....•.....
Electric Current......................................•........•........•......
Series Ci rcu it ......................•...•..............•................•......
Parallel Circuit.........................•......................•...............
Current Flow............••....•...•.....................•...•...•....•.......
Magnetism ..............•.............•........•....•.......•...•....•.......
Magnetic Fields .........•.........•...•..••.....................•....•....••..
Electromagnetism .......•....••...•......••....•....•...........••...•.....•..
•
•
•
1-2
2-3
3·4
5
6
6
7
8-9
A.C. GENERATORS................•...•...•...•.....•............•...•.....•...
Induction .................••..........•.....•...••....•...........•.....•...
A.C. Generator Operation ....•....•.......•...•.....•...•.......•.........••....
8
RECTIFIERS ........................•...•.........•............•.........•....
Half-Wave Rectifier. . . . . . . . . . . . . . . . . . .
. .••....•...••..••...•. _.•...........
Full-Wave Rectifier. . .
. ..................•....•....•...•...•. _.......•. _...
10 - 11
10 - 11
11
SOLID STATE CURRENT LIMITER .........•.......•.....•.......•....•.........•.
12
THREE-PHASE CHARGING SySTEMS......•..... __ .••............•........•.....•.
12 - 15
BATTERIES ...........................•.............•...•...•...•....•....••..
Battery Cell Construction ......•.. _•...•...•.. _.•....•....•...•...•.........••..
Battery Cell Operation ......•......... , ..••........•....•...•...•....•.........
Specific Gravity......................•.......•....•........•...•...•.....•....
Battery Cell Voltage .............•....•............•...•........•.........•....
Battery Ampere·Hour Capacity ............••..•.........••...•...•....•....•.....
Battery Identification .................................••...•.............•.....
Dry-Charged Batteries .............................•...•...••...•........•......
Preparation of New Dry-Charged Motorcycle Batteries .....................•....• , .....
Electrolyte Level. ...................................•........•...•............
Battery Vent Tube. .
. .................................•.......•....•.......
Battery Cleaning ..........................•.........•...•........•...••.......
Battery Storage ......................•...•....•.........•..•....•.............
Battery Charging Equipment ....••..........•....•.............•...•....•.....•..
Battery Safety ...................•.......•...••....•...•........•...•.....••..
16 - 25
16
IGNITION SySTEMS ...........................•.........•......•....•.....•....
Battery Ignition..................•...•.............•...•...••...•...•.....•...
High Tension Magneto Ignition ......•...•...•....•....•....•...•...•...•.....•...
Low Tension Magneto Ignition .....•..••..••...•.....•...••...•...•...•.....•....
Energy Transfer Ignition .............................•...•.......••...•....••...
Capacitor Discharge Ignition ...............•...••....•........•...•...•..........
Ignition Advance ............................•....•.........•............••....
Centrifugal Ignition Advance Operation ..........•...•....••...•...•...•...••......
Dwell Angle and Contact Point Gap Adjustment..................•...•...............
Ignition Timing Adjustment ............................•....•...................
Ignition Timing Marks ..........•...•...•...•.....•........••..•...••...••......
© Amencan
b
1-7
8-9
17
17 . 18
19
20
20 - 21
21
21 - 22
22
23
23
24
24
25
25 - 46
27 - 28
29
30
31
32·33
33
34
35
36·37
38
Honda MotOr Co., Inc. 1977
TABLE OF CONTENTS (CONTINUED I
PAGE
SUBJECT
IGNITION SySTEMS
.
Procedure for Adjusting Contact Point Gap and Ignition Timing on Honda Single Cylinder
Engines Without an Adjustable Contact Point Base Plate
.
Procedure for Adjusting Contact Point Gap and Ignition Timing on Honda Single and Twin
Cylinder Engines Having One Set of Contact Points and an Adjustable Contact Point
Base Plate
.
Procedure for Adjusting Contact Point Gap and Ignition Timing on Honda Twin Cylinder
Engines Having Two Sets of Contact Points
.
Procedure for Adjusting Contact Point Gap and Ignition Timing on Honda Four Cylinder
Air·Cooled Engines
.
.
Procedure for Adjusting Contact Point Gap and Ignition Timing on the Honda GL·' 000
Spark Plugs ..............................................................•...
Spark Plug Heat Range
.
25·46
ELECTRIC STARTER SySTEM
.
D.C. Motor Operating Principle ........................................•..........
Starter Motor Construction ............•.....•...................................
Starter Motor Service
.
Electromagnetic Starter Switch ...•....•..........................................
Overrunning Clutch ............•....•................•.........................
47·52
47·48
49
50
51 ·52
52
LIGHTING SYSTEM .....................•....................•.................
Headlights .................................................•.................
Taillight and Stoplight
:
.
Stoplight Switches.................................•...................•.......
Turn Signal Lights ......•......................................................
53·57
53·54
55
55·56
56·57
HORN ....................................................................•...
57
FUEL LEVEL AND COOLANT TEMPERATURE GAUGES/COOLING FAN
58
GLOSSARY
.
38·39
39
40
41
42
43·44
45·46
, ....................•.....•....
59·60
ELECTRICAL SYSTEM TROUBLESHOOTING ....•..................................
61 . 64
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HONDA MOTORCYCLE ELECTRICAL SYSTEMS
BASIC PRINCIPLES OF ELECTRICITY AND MAGNETISM
"
,
Electric Cu rrent:
~
A basic knowledge of electricity and magnetism is necessary for understanding the construction and operation of motorcycle electrical systems.
Electric current flowing through a wire can be compared to water flowing through a pipe. The laws governing electric circuits are easily explained by this analogy.
Water will flow through the pipe from the full tank to
the empty tank (Fig. 1) until the water level is even in
both tanks. Pressure Iweight of water in the full tank
or pressure supplied by attaching a pump) is required
to cause the water to flow. A valve can be installed to
open or close the water passage.
t
Similarily, electrical current will flow through a wire
(Fig. 2) due to electrical pressure created by the battery
or a generator. A switch can be installed to open or
close the circuit.
Fig. 1 Hydraulic Analogy to Electrical Circuit
Water pressure is measured in pounds per square inch,
while electrical pressure is measured in VOL TS.
Rate of water flow, measured in gallons per minute,
is analogous to rate of electrical current flow which is
measured in AMPERES.
SWITCH
•
t
Water will have a lower rate of flow through a smaller
or longer pipe due to increased resistance. Similarily,
electric current will have a lower rate of flow through
a smaller or longer wire. Partially closing the water
valve in Fig. 1 decreases water flow by adding resistance,
just as the resistor in Fig. 2 decreases current flow.
Electrical resistance is measured in OHMS.
BATTERY
Fig. 2 Electrical Circuit
1
BASIC PRINCIPLES OF ElECTRICITY AND MAGNETISM
The relationship between pressure (volts), current flow (amperes), and resistance (ohms) is known as
OHM'S LAW. Given any two values of a circuit, we can calculate the third value.
AMPE RES = VOLTS -7- OHMS
VOLTS
= AMPE RES X OHMS
OHMS
= VOLTS -7- AMPE RES
OHM'S
LAW
Electrical power is measured in WATTS. The analogous hydraulic term would be horsepower. Increasing the
electrical pressure (volts) or increasing the rate of current flow (amperes) increases electrical power output
or consumption (watts).
WATTS
= VOLTS
X AMPERES
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Series Circuit:
An electrical circuit is said to be in series when
connected as shown in Fig. 3. Current flows through
the switch and through each lamp, or other equipment, in sequence and returns from the last one to
the battery. A hydraulic analogy to the series circuit
is shown in Fig. 4.
Fig. 3 Series Circuit
Fig.4 Hydraulic Analogy to Series Circuit
2
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In a series circuit, resistance (ohms) increases as the
number of lamps or other equipment is increased.
As shown by Ohm's Law, increasing the resistance
(ohms) will decrease current flow (amperes) unless
pressure (volts) is also increased.
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BASIC PRINCIPLES OF ElECTRICITY AND MAGNETISM
If one lamp in a series circuit burns out, or is removed, the circuit becomes incomplete, and all lamps go
out. The same effect can be produced in Fig. 4 by shutting down anyone of the turbines. For this reason,
motorcycle lighting equipment, such as headlight and taillight, are connected in parallel rather than in
series.
Switches and fuses, however, must be connected in series with the equipment they control or protect.
•
When an ammeter is used to check current flow, it too must be connected in series, so that all current in
the circuit flows through the meter.
Parallel Circuit:
LAMPS
An electrical circu it is said to be in parallel when
connected as shown in Fig. 5 & 6. Current flowing
through anyone lamp or other component will
complete a circuit, returning to the battery through a
common ground connection or wire. If one lamp
burns out or is removed, the others will remain lit.
BATTERY
Note that the switch is connected in series. When the
switch is turned off, the circuit will be incomplete,
Fig. 5 Parallel Circuit Two Wire System
and all lamps will go out simultaneously.
A considerable amount of wire can be saved by
utilizing the frame and engine to complete the circuit.
•
•
Ground symbols (-:i=') shown
in
Fig. 6 indicate
attachment to the frame or engine. A return wire
SWITCH
(Fig. 5) is necessary only when the electrical compo·
nents are mounted in such a manner that they are
insulated from the frame and engine.
BATTERY
Fig.6 Parallel Circuit One Wire System
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3
BASiC PRINCIPLES OF ELECTRICITY AND MAGNETISM
lydraulic analogy to the parallel circuit is shown in Fig. 7. If one turbine is shut down, the others will
"Jntinue to operate and it can be clearly seen that more water will flow as more valves are opened. Opening
additional passages reduces the total resistance. Similarly, as more lights are added in Fig. 5 & 6, the total
resistance of the circuit (ohms) is reduced and more current (amperes) flows from the battery to operate
the additional lights without requiring a voltage increase.
":ig. 7 Hydraulic Analogy to Parallel Circuit
The hydraulic analogy in Fig. 8 is offered as a plumber's conception of a motorcycle electrical system.
WATER lEVEL -;;;~--------.w-!
(STATE OF CHARGE)
RESERVOIR
(BATTERY)
~=>'1;=(;;>.
-----------iii~l1~:"~~~::1:~=t~
l!!
I.~~+-
r':l
::-:::=--Ir--f-......:~;.;...-~If.::"~
~~~~~;t::=
Fig. 8 Hydraulic Analogy to Motorcycle Electrical System
4
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VALVE LINKAGE
(BRAKE LIGHT LINKAGE)
VALVE
(BRAKE LIGHT SWITCH)
-PULL CHAIN
(BRAKE PEDAL)
TURBINE - - -__~
(STARTER MOTOR)
PUMP
(GENERATOR)
•
VALVE
(MAIN LIGHT SWITCH)
•
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•
-
BASIC PRINCIPLES OF ELECTRICITY AND MAGNETISM
Current Flow.
Electric current does not really flow like water, of course. This is simply a convenient analogy for
•
•
explaining electrical circuits. Electric current consists of electrons (the smallest possible units of negative
electrical charge) moving from atom to atom within the wire.
The outer electrons are most easily freed from the atom.
NUCLEUS
When voltage is applied, they will travel a short distance
and collide with other atoms. The collision will knock
other electrons free, and the process continues with
free electrons moving by collision toward the positive
terminal in the electrical circuit.
Copper wire is a good conductor of electricity because
its atoms have a large number of easily freed electrons
in their outer orbits. Insulators, such as rubber, glass,
ELECTRON
and plastics have few free electrons and are poor con·
ductors of electricity.
Fig. 9 Atom
Before the nature of electricity was understood, it was thought that "electric current" flowed from the
positive terminal of the voltage source, through the circuit, to the negative terminal, and all technical
publications were written accordingly.
When it was discovered that electrons flowed from the negative terminal, through the circuit, to the positive
terminal, it was too late to change all the books. Nor could terminals be relabeled to reconcile electron
flow with old theory, as there was too much old-theory equipment in use, and relabeling terminals would
cause confusion.
•
•
Thereafter, technical publications referred to "conventional current" (old theory) as flowing from positive
to negative, while "electron flow" (new theory) ran from negative to positive.
With the advent of transistor technology, it became useful to consider electric current as something that
flows in both directions. The electrons constitute current flowing from negative to positive, while the
"holes" vacated by those electrons constitute current flowing from positive to negative.
For most purposes, the direction of current flow is of no concern, so long as you are careful to connect
electrical components in proper polarity.
5
BASIC PRINCIPLES OF ELECTRICITY AND MAGNETISM
etism:
Magnetism is an invisible force, the nature of which has not been fully determined. The properties of mag·
netism are well known, however, and we are all familiar with the ability of a magnet to attract, and be
attracted by, iron and magnetic alloys.
Magnetic force is concentrated in the ends of the magnet,
called poles. The poles are labeled north and south from
the fact that a compass needle, which is simply a thin bar
magnet, aligns itself with the north and south magnetic
poles of the earth.
Think of the north and south poles of magnets as "north
seeking" and "south seeking" with reference to the earth.
This orientation will avoid conflict when considering that
the north pole of a magnet is attracted to the "north" mag·
netic pole of the earth.
Fig. 10 Compass
Unlike poles (north seeking pole of one magnet and south seeking pole of another magnet) attract each
other, while like poles (two north seeking poles or two south seeking poles) repel each other. This princi·
pie, which makes a compass operate, is also used to explain the operation of such devices as electric motors
and solenoids. The force of attraction or repulsion is increased when the magnets are made stronger or
,n brought closer together. The force is' decreased when the magnets are weaker or farther apart.
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Magnetic Fields:
Magnetic lines of force are considered to emanate from the north pole of the magnet, pass through the
surrounding space, reenter at the south pole, and complete the circuit by passing through the magnet it·
self.
LINES OF
FORCE
Fig. 11 Magnetic Fields
b
When a magnet is used to pick up iron particles, most
of them will be attracted to the ends (poles) of the
magnet. Magnetic force is greatest in the poles because
all lines of magnetic force must pass through the poles
to complete their circuits. The strength of a magnet is
determined by the concentration of these lines of
force.
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•
BASIC PRINCIPLES OF ElECTRICITY AND MAGNETISM
Electromagnetism:
,-
When an electric current flows through a wire, this
sets up a magnetic field surrounding the wire. This
field is regarded as magnetic lines of force encircling
the wire (F ig. 12).
t:7';-\"\"C.~\
•
When a soft iron core is inserted into the wire coil,
the lines of magnetic force inside the coil will tend
to travel through the iron (Fig. 14). because it pro·
vides a better magnetic path than air. This property
of iron, called permeability, concentrates the lines
of force in the center of the coil, strengthening the
magnetic field. The combination of an iron core in
a coil wire becomes an electromagnet.
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r-"~\
Ill',; . • :~i
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!It
II
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\\\';:/1
If the wire is wound in a coil, the magnetic lines of
force form a pattern which encircles all adjoining
loops of the wire (Fig. 13). This establishes a magnetic field which resembles that of a bar magnet,
though many lines of force are dissipated between
the loops of the coi I.
-,
'.:....'
1- \
I/",.~\\
111/-',,\\
~\:
,,~_'I"
--,..
~~
__+1
Jl:;
\
.::-'://
---
Fig. 12 Magnetic Field Surrounding a Wire
,
.... - - - 4 - - - - .... - - - - . . .
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If,.....
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\
"-
\
\
' .....
-
, ..... ,
I
~\
, .... ,
\
I
\
I~'
_
--
f
/
".,./
.=- =-: -::. ..-.:. -
-
f'-~-\--
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I
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I
( . . '\
)
-•.::..:::--..::=- s ... -___
- , ......,...
_".
,
,
.... - - ....... - - - - - .... - - - - -
_....."""'!j__~;~~--
..:::~
----
....
N
.......
.....
.......
'\\
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+
When the electric current is switched off, the lines of
force collapse, and the soft iron core immediately
loses its induced magnetism.
Fig. 13 Magnetic Field of a Wire Coil
A soft iron core is used to produce a temporary electromagnet in this manner, but a bar of sreel, once magnetized, will retain its magnetism indefinitely and is called a permanent magnet. The magnets shown in Fig.
11 are made of steel or other magnetic alloy _ Soft iron is used as the core of a temporary electromagnet.
•
•
SOFT
IRON
CORE
Fig. 14 Electromagnet
7
A.C. GENERATORS
':luction:
Induction is the process by which a magnetic field is used to create electric current. It is the operating principle of the generator.
We have seen that wherever an electric current is flowing, a magnetic field is present. Conversely, wherever there is a magnetic field, an electric current can be induced.
An electric current is induced in a wire coil whenever
lines of magnetic force are cut by the wires. The
strength of the induced voltage depends on three
factors:
1. The number of windings in the wire coil. The more
windings there are, the more times the magnetic
lines of force will be cut.
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2. The strength of the magnetic field. Stronger magnets have more lines of force.
DIRECTION OF CURRENT FLOW
3. The speed with which the lines of magnetic force
are cut by the wires.
Fig. 15 Elementary A.C. Generator
A.C. Generator Operation:
Fig. 15 & 16 show an elementary A.C. generator.
A permanent magnet
is suspended with in a soft
iron frame
which completes the circuit for the
permanent magnet's lines of force. The soft iron frame
thereby becomes a temporary magnet, concentrating
lines of magnetic force around the wire coil
CD
CD
•
0.
CD
DIRECTION OF CURRENT FLOW
G)
o
o
When the permanent magnet
is rotated 1800 ,
the magnetic polarity of the soft iron frame
is
reversed. With each 1800 of rotation, the magnetic
lines of force around the soft iron frame collapse and
then reestablish themselves in the opposite direction.
Each time the lines of force collapse and rebuild, they
are cut by the wire coil
and an electric current
is induced in the wires.
CD
0 '
PERMANENT MAGNET
SOFT IRON FRAME
WIRE COil
The current thus generated is called "A. C." (alternating currentl because the direction of current flow
reverses each time the magnetic field is reversed.
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•
Fig. 16 Elementary A.C. Generator
8
t
c
A.C. GENERATORS
The elementary A,C, generator shown in Fig, 15 &
16 has a two-pole rotating magnet and a two-pole soft
iron frame, The induced current therefore reverses
every 180 0 , A full cycle is completed every 360 0
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SIX·POLE MAGNET
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If the motorcycle is equipped with a six-pole rotating magnet and a six-pole soft iron frame, as shown
in Fig, 17, the induced current will reverse every 60 0 ,
•
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~COIL
ASSEMBLY
Fig. 17 Six -Pole A.C. Generator
and a full cycle will be completed every 1200 More
current is generated because there are a greater number
of generating coils in operation, and magnetic lines of
force are cut more frequently,
An A,C_ generator can be constructed with any even
number of poles, It is common practice to use one set
of coils to generate ignition current and another set to
Fig. 18 Hookup for Controlling Number of
Coils Used
generate lighting current (Fig. 20), or to use one set of
coils to generate the current needed for daytime opera-
STATIONARY COil
tion with lights off and additional coils for nighttime
ASSEMBLY
operation with Iights on (F ig. 17, 18, 19),
Fig.
18 illustrates the hookup for controlling the
number of coils to be utilized in the generators shown
in Fig. 17 & 19_ Wire A carries the current produced
by only one set of coils, and wire B carries the current
ROTATING MAGNET
produced by the other two sets of coils, Switch connections enable the motorcycle to be operated using
A only, or A plus B.
The generator can be constructed with the rotating
•
•
magnet at the center of the coil assemblies (Fig. 19)
or with the coil assemblies at the center of the rota-
Fig. 19 A.C. Generator with Magnet Inside
Coils
.?
~
~
ROTATING MAGNET
ting magnet (Fig. 20). The effect is the same either
way. The generator would also function if the magnet
were stationary and the coil assemblies rotated, but
this is not done as the coil assemblies are more susceptible to damage by centrifugal force.
Fig. 20 A.C, Generator with Coils Inside
Magnet
9
RECTIFIERS
•
NO CURRENT FLOW
--~"""'-HIGH CURRENT FLOW
Fig. 21 Symbol for Rectifier Element
SELENIUM
HALf-WAVE
SILICON DIODE
RECTIFIER
RECTIFIER
HALF-WAVE
A rectifier is a device for converting alternating current
IA.C.) to direct current ID.C.I. Because the A.C.
generator produces only alternating current and the
battery can only be charged by direct current, a rectifier must be installed in the circuit between the A.C.
generator and battery.
Motorcycle rectifiers are constructed using selenium
plates or silicon diodes which act as one-way valves,
permitting current flow in one direction and resisting
all current flow in the opposite direction.
The symbol used to represent a rectifier on wiring
diagrams incorporates an arrow which points in the
direction that conventional current ISee Current Flow,
page 5) is permitted to flow (Fig. 21).
SILICON DIODE
FULL-WAVE
RECTIFIER
SELENIUM
FULL-WAVE
RECTIFIER
Rectifier elements (selenium plates or silicon diodes)
can be used individually as half-wave rectifiers, or
grouped in bridge circuits as full-wave rectifiers.
Half-Wave Rectifier:
Fig. 22 Honda Motorcycle Rectifiers
A.C. generator output can be illustrated as a wave
form IFig. 23) corresponding to the movement of an
ammeter needle as current increases and decreases in
one direction, and then increases and decreases in the
opposite direction when the A.C. generator's magnetic
field is reversed.
AMMETER-0
+
A.C.
CURRENT
•
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•
I
of--------\.------;------j'------------'t;------;---+--
•
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•
Fig. 23 Alternating Current Wave Form
10
«
----
----
RECTIFIERS
J
If a selenium plate or silicon diode is connected
between the A.C. generator and the battery, as illustrated in Fig. 24, current flow comprising the
positive half of the wave form will be passed to the
CD
battery, while negative (reverse) flow will be pre-
@
@
vented.
A.C. GENERATOR
HALF-WAVE RECTI FIER
BATTERY
+
o
A half-wave rectifier utilizes half the generator's
WAVE FORM OF RECTIFIED CURRENT
output, but is sufficient for use on some of the
smaller Honda models. A greater flow of direct
Fig. 24 Half-Wave Rectification
current can be obtained through a full-wave rectifier which inverts the negative half of the wave form.
t
~
Full-Wave Rectifier:
The simplest full-wave rectifiers used on Honda
-
t
--
t CD ,
t
+
motorcycles are made with four selenium plates or
I
silicon diodes connected as shown in Fig. 25 (six
diodes are used in rectifiers for three-phase A.C.
generators). Each time the generator's alternating
current reverses direction,
t
t
,
the rectifier elements
provide an alternate path to the battery. A full-wave
+
CD
rectifier converts the fu II output of the A.C. generator to direct current and passes it to the battery.
CD
CD
A.C. GENERATOR
@
@
BATTERY
FULL-WAVE RECTIFIER
WAVE FORM OF RECTIFIED CURRENT
Fig. 25 Full-Wave Rectification
11
SOLID STATE CURRENT lIMITER/THREE·PHASE CHARGING SYSTEMS
,nerator output increases with engine rpm. On models equipped with low output generators, this does not
any problem. Models equipped with higher output generators require a current limiter or voltage
re'gulator to protect the battery from being overcharged during prolonged high rpm operation.
•
~(eate
The solid state current limiter uses a zener diode which differs from the previously described rectifier
diodes in that it does not always completely block reverse current. A reverse-biased zener diode will pass
current when voltage exceeds a predetermi~ed level, and then it passes only the amount of current exceeding that level. A solid state current limiter, containing a zener diode, is connected in the charging circuit in
parallel with the battery to bleed off the excess current that would otherwise overcharge the battery at high
rpm_
•
•
+
CD
A.C. GENERATOR
@
FUll·WAVE RECTIFIER
@
CURRENT LIMITER
®
BATTERY
•
SOLID STATE CURRENT LIMITER
Fig. 26 Charging System with Solid State Current Limiter
THREE-PHASE CHARGING SYSTEMS
A three-phase charging system is used in Honda four cylinder motorcycles. This system is composed of a
three-phase A.C. generator, a six-diode rectifier, and a voltage regulator.
Fig, 27 Alternating Current Wave Form from
Three-Phase A.C. Generator
The generator is referred to as "three-phase"
because it has three single-phase windings spaced
so that the voltage induced in each winding is
1200 out of phase with the voltage in the other
two windings. A representation of the alternating current wave forms (Fig. 27) is similar in
appearance to the wave forms which would be
generated by three separate single·phase generators (see pages 8 & 9) phased 1200 apart.
•
12
«
THREE·PHASE CHARGING SYSTEMS
r
The three-phase A.C. generator used in Honda G L·1 000
engines has two major components; rotor and stator
(Fig. 28). The rotor is permanently magnetized and revolves around the stator. Current is generated in the
manner described on pages 8 & 9, but the stator windings produce a three-phase output.
Three-phase A.C. generators used in other Honda four
•
cylinder engines have three major components (Fig. 29).
The rotor is bolted directly to the end of the cran kshaft
Fig. 28 3·Phase Generator (GL·1 000)
and revolves in the space between the field coil and
stator. The field coil and stator are held stationary in
_--------ROTOR
the generator housing.
Unlike other Honda motorcycle generators, the rotor
".,
is not permanently magnetized, but is temporarily magnetized through interaction with the field coil. Current
from tre battery to the field coil determines the
strength of the magnetic field and hence the output of
FIELD COil
the generator.
Fig. 29 3·Phase Generator (other models)
Voltage Regulation for A.C. Generators Equipped
with Field Coils (all Honda four cylinder models
except GL-1000):
The voltage regulator (Fig. 30) for these generators
provides three operating modes which
are selected
according to the battery's state of charge. The regu-
Fig. 30 Voltage Regulator (exterior view)
lator enables low battery voltage to cause high generator output, and vice versa.
ARMATURE
Changes from
one operating mode to another are
achieved by a relay coil and contact points within the
•
1i!!ti!ll..~~~rCONTACT POINTS
RELAY COIL
regulator (Fig. 31). The relay coil is an electromagnet
(see page 7) which can cause the circuits to be switched
by attracting the contact point armature.
Fig. 31 Voltage Regulator (interior view)
13
THREE-PHASE CHARGING SYSTEMS
MODE 1 (Fig. 32) - Battery Voltage is Low:
Current flows from the battery to terminal I of the voltage regulator. Inside the regulator. current flows
through a relay coil and to ground through terminal E.
Because battery voltage is low (the battery needs charging). there is not enough current flowing through the
regulator relay coil to open the contact points, so current also flows from terminal I. through the contact
points, through terminal F. and directly to the field coil.
In this mode. the battery is directly connected to the field coil and provides the maximum field current
(1.6 amps). Max imu m field current causes high generator output for high battery charging voltage.
CABLE
RIW
R/W
RECTIFIER
r---]
G
Y
R
12
vee
BATTERY
1
T
I
Y
I
.. I
Y
IGNITION SWITCH
aL
BL
r------------------
TERMINAL F 1 RELAY ARMATURE
--;.
w
~~C'-'--.
RELAY~
COIL
b11n
/0
'-
Y r-,--,Y'---J
~1lOO())
TERMINAL I
REGULATOR
ALTERNATOR
R
'-
--
Y
Y
Y
Y
r.
\II.'
G
G
I
~
I
I
I
:
I
I
I
I
I
~-- t-~-~5~:------~---J
10n FIELD RESISTOR
TERMINAL E
o
~
o
..I
o....
FIELO COIL'-----'
' - - - - - - - - - - - ' CONNECTOR
~
Fig. 32 Three-Phase Charging System. Red lines show MODE 1 current path.
MODE 2 (Fig. 33) - Battery Voltage is Normal:
With normal battery voltage. there is sufficient current flowing through the regulator relay coil to open the
contact points. Current may now reach terminal F only by passing through a resistor which reduces field
current. Lower field current results in lower generator output.
14
1\
~
THREE-PHASE CHARGING SYSTEMS
...
RECTIFIER
CABLE
R!W
R!W
R
G
v
R
12VDC
-
--
BATTERY
v
I
v
IGNITION SWITCH
CONNECTOR
R
..
I
OJ
BL
BL
REGULATOR
ALTERNATOR
TERMINAL 1
r-----------------~
TERMINAL I RELAY ARMATURE
F
I
W
V
V
V
V
V
W
I
I
,
,
:
I
I
v
I
I
I
I
I
I
RELAY Jc:>
COil
gl1::
I
L__
:
I
+
I
I
I
_~5~~
C
<l
o
-'
J
o...
~ TERMINAL E
10n FIELD RESISTOR
G
CONNECTOR
Fig. 33 Three-Phase Charging System. Red lines show MODE 2 current path.
MODE 3 (Fig. 34)Battery Voltage is Excessive:
CABLE
R/W
I
12VDC
-=-
BATTERY ~
When battery voltage is excessive, there is enough
current flowing through the regulator relay coil
to cause the contact points to complete a ground
circuit. Current flows from the battery, through
resistance, to ground. No current reaches the field
coil, and therefore there is no generator output.
I
IGNITION SWITCH~
RELAY
ARMATU~E
TERMINAlFr--
BL
Jl.'
~'I
I
:
I
RELAY:~
COIL
,g--:
""'r:,
I
"11n
I
II
P
I~~
L_+
I
lan
Bl
REGULATOR
.....L...TERMINAl
-----------r;'
I
_~
FIELD
RESISTOR
I
:
J
I
2sQ -.JTERMINAL E
!
c
<l
o
-'
o...
Fig. 34 Three-Phase Charging System.
Red lines show MODE 2 current path.
15
BATTERIES
"he battery serves as an energy reservoir, storing the generator's electrical output in chemical form. The
battery's chemical energy is converted again to electrical energy for operating the starter motor, or when
needed for lighting and ignition current.
When the engine is operating at a speed too low for the generator to supply all the lighting and ignition
current needed, the battery discharges, converting its chemical energy into the needed electrical energy. At
normal riding speeds, generator output is sufficient to recharge the battery, restoring its chemical energy.
Some motorcycles do not require batteries. Dirt bikes, especially those which have no lighting equipment,
do not require an energy reservoir; their ignition current is supplied solely and directly by the generator.
These machines are designed without batteries or starter motors for simplicity and to reduce weight.
A battery is required on all motorcycles equipped with starter motors, because the starter motor must operate when the engine is at rest, and the generator cannot supply current until the engine is running. Further,
starter motors consume large amounts of current. A battery is also necessary, or at least helpful, if a large
amount of lighting current must be delivered at idle speed.
•
•
•
Battery Cell Construction:
Motorcycles are normally equipped with lead-acid batteries. Other metals and electrolytes can be used to
construct batteries, but the ordinary lead-acid combination produces the highest cell voltage for the lowest
cost.
A simple battery cell is illustrated in Fig. 35. Groups of lead plates are stacked parallel to each other, separated by ,"teets of insulating material. The cell is filled with dilute sulfuric acid when prepared for service.
Plates connected to the negative terminal of the
battery are made of plain lead (Pbl. Plates can·
nected to the positive terminal are made of lead
peroxide IPb021, which can be distinguished by its
brown color.
The plates are arranged alternately; negative
positive - negative, etc. There is a negative plate
at each end of the plate group; therefore the cell
has one more negative plate than positive plate.
There is no technical reason for using negative
plates at both ends; it is simply common practice.
G)
ELECTROLYTE
@
@
POSITIVE TERMINAL
NEGATIVE TERMINAL
@)
®
®
NEGATIVE PLATE IPbl
SEPARATOR
Separator sheets of resin treated paper and fiberglass, or other non-conductive materials, are porous
to permit the passage of electrolyte, while insulating the lead plates from each other to prevent
short circuiting. Additional separators may be
placed at the ends of the plate group as packing
material, though this is not essential.
•
•
POSITIVE PLATE IPb021
Fig. 35 Lead-Acid Battery Cell
16
t
BATTERIES
r
'.
Battery Cell Operation:
Chemical action between the electrolyte and the cell plates produces an electric current. As previously
stated, the positive cell plates are lead peroxide (Pb02) and the negative cell plates are plain lead (Pb).
When a load is connected between the battery terminals and the cell discharges, the sulfuric acid electrolyte (H2S04) divides into H2 and S04. The H2 combines with oxygen in the positive plates to form water
(H20), while the S04 combines with the lead (Pb) of both plates to form lead sulfate (PbS04). When the
battery is recharged by the generator, the chemical process is reversed.
DISCHARGE
Pb02 + Pb + H2S04 = 2PbS04 + 2H20 + ELECTRICAL ENERGY
,
CHARGE
As discharge continues, the amount of lead sulfate on the plates increases until the sulfate coating becomes
so thick that the weakened electrolyte cannot effectively reach the active materials (lead and lead peroxide). When this happens, chemical reaction is retarded and the output of the cell is reduced. In practice,
the battery should not be permitted to discharge to this extent, because thick coatings of lead sulfate are
difficult to remove in charging. When a battery has been allowed to remain in a discharged condition for
a considerable time, sulfation is visible as a white deposit on the plates. Cells which have become badly
sulfated may be permanently impaired.
Specific Gravity:
When the cell is being charged, lead sulfate is removed from both positive and negative plates, and sulfuric
acid is again formed. In the process, the water content of the electrolyte is decreased, and the acid content
of the electrolyte is increased.
Sulfuric acid is heavier than water. Therefore, increasing the sulfuric acid content increases the density of
the electrolyte. Specific gravity is a measure of the density of the electrolyte, relative to water. Water has
a specific gravity of 1.000.
•
•
The cell's state of charge is indicated by the specific gravity (density) of its electrolyte and can be checked
with a hydrometer (Fig. 36) .
The specific gravity must be high enough to promote chemical action in the cell, though excessive acid content can shorten cell life. A well charged cell in a motorcycle battery should have a specific gravity of
1.260 - 1.280. A specific gravity of 1.200 - 1.260 indicates a partial charge. If the specific gravity falls
below 1.200, the battery should be recharged as soon as possible; it should not be permitted to remain for
a long time in a discharged state.
The specific gravity figures given in the preceding paragraph apply at a standard reference temperature
of 77 o F. The specific gravity reading for a given electrolyte density will vary slightly with temperature
changes. At high temperatures, lower specific gravity readings will be obtained, and vice versa.
11
BATTERIES
•
•
•
HYDROMETER
•
Electrolyte level in the syringe tube must allow
the float to operate freely; do not overlill or
underfill.
For an accurate indication of state of charge,
do not test specific gravity immediately after
adding water to the cell or during initial reo
charging.
FULL CHARGE
DISCHARGE
f
Fig. 36 Measuring Specific Gravity With a Hydrometer (calibrated float reads specific gravity)
As a temperature correction factor. add 0.001 to the specific gravity reading for each 3 0 F above 77 0 F.
Subtract 0.001 from the specific gravity reading for each 30 F below nOF. Thus, if a specific gravity reading of 1.260 is obtained at 50 o F, the corrected specific gravity is 1.251.
BATTERIES
r
•
•
Battery Cell Voltage:
Cell voltage is basically determined by the plate material
and electrolyte chemicals used. A lead-acid cell produces
a nominal 2 volts.
Regardless of cell size or the number of cell plates (these
factors affect ampere-hour capacity), if the plates are lead
and the electrolyte is sulfuric acid, then the nominal cell
voltage is 2 volts.
Three 2 volt cells are connected in series to make a 6 volt
battery (Fig. 37). Six 2 volt cells are connected in series to
make a 12 volt battery (Fig. 38).
Note that the cells must be connected in series in order for
the cell voltages to be additive. If a number of 2 volt cells
were connected in parallel, you would simply have a large
2 volt battery with greater ampere-hour capacity.
r
Fig. 37 6 Volt Battery
(three 2 volt cells)
The actual, measured voltage of a lead-acid cell will be
slightly more or less than the nominal 2 volts, depending
on the specific gravity of the electrolyte.
Open circuit voltage, applicable while the battery is not
connected to any load, can be calculated as follows:
VOLTS
= SPECIFIC
GRAVITY
+ .84
Thus, the open circuit voltage for a cell with a specific
gravity of 1.280 is 2.12 volts. Six such cells, connected in
series, will produce a battery open circuit voltage of 12.72
volts.
•
•
When a cell discharges, there is a gradual decrease in
voltage due to increasing internal resistance as lead sulfate
coats the plates and electrolyte weakens. After a gradual
decrease to roughly 1.75 volts, the cell's capability is exhausted, and voltage drops sharply below a usefu I level.
Voltage generated by the motorcycle's charging system
must be greater than the battery's nominal voltage.
Charging voltage must equal the battery's open circuit voltage plus the voltage necessary to overcome internal resistance within the cells.
2
V
2
V
Fig. 38 12 Volt Battery
(six 2 volt cells)
19
BATTERIES
B.
,ry Ampere-Hour Capacity:
Battery capacity (the ability to deliver electrical energy) is expressed in terms of ampere-hours. Ampere-
•
hour ratings are calculated by multiplying battery discharge current, in amperes, times the number of hours
the battery is capable of supplying that current.
•
However, in order for a battery's advertised ampere-hour rating to have any meaning, it is essential to know
the particular time period for which the ampere-hour rating was measured. If a battery is slowly discharged,
producing low amperage current over a period of many hours, it will produce far more ampere-hours of
•
current than if it is discharged at a very rapid rate, such as occurs when operating a starter motor.
A 12 ampere-hour battery, based on a 10 hour discharge rate, will deliver 1-2 amperes of electrical current
for a 10 hour period (1.2A X 10 hrs.
= 12
ampere-hours). The same battery will not deliver 12 amperes
for 1 hour; more likely it would deliver about half that much at a 1 hour discharge rate.
For Yuasa batteries used in Honda motorcycles, a period of 10 hours has been established as the discharge
time in rating battery capacity. American automotive batteries customarily use a 20 hour rate for advertised ampere-hour capacity. A 5 hour rate is standard for aircraft batteries.
T
3mpere-hour capacity of a battery depends mainly on its total effective plate area_ A larger battery,
with bigger plates or more plates in parallel, will have a higher ampere-hour capacity. Greater ampere-hour
capacity can also be obtained by connecting two or more batteries in parallel. A battery will also have a
•
somewhat higher ampere-hour capacity at summer temperatures than at winter temperatures, because
higher temperatures accelerate chemical reaction. However, cell temperatures in excess of 113 0 F (45 0 C)
will reduce the service life of the battery.
Battery Identification:
A model identification code is imprinted on the side of all Yuasa motorcycle batteries (Fig. 39). In most
f
(but not all) cases, this code will correspond to the JIS (Japan Industrial Standards) classification number
for that type of battery.
Where Japanese-made batteries are concerned, technical literature and battery interchangeability charts
usually refer to the JIS number, and it is useful to know how to decipher the code .
•
20
f
BATTERIES
12N12A-4A-1 CODE INTERPRETATION
12-- Nominal voltage (12 volts)
N - - Initial for Nippon (Japan)
12-- Ampere-hour capacity at 10 hour discharge rate
(12 AH)
A - - JIS battery identification symbol
4 - - Terminal position code
A - - Vent tube position code
1 - - Yuasa battery identification number
•
6N6-3B CODE INTERPRETATION:
Yuasa 12N 12A-4A-1 Battery
Number preceding letter "N" indicates battery voltage_ Number immediately following "N" indicates
ampere-hour capacity. Other symbols identify the physical construction of the battery.
6
N
6
3
B
Nominal voltage (6 volts)
Initial for Nippon (Japan)
Ampere-hour capacity at 10 hour discharge
rate 16 AH I
Terminal position code
Vent tube position code
Fig. 39 Battery Identification Codes
Dry-Charged Batteries:
Yuasa batteries for Honda motorcycles are dry-charged, which means that the cell plates are charged and
then dried before the battery is assembled by the manufacturer. Assembled batteries are sealed to keep out
moisture. This process enables batteries to be stored for long periods of time without deterioration.
Preparation of New Dry-Charged Motorcycle Batteries:
•
•
1. Unseal the battery and attach the vent tube. The vent tube must be unobstructed in order to vent hydrogen and oxygen that is liberated during the charging process (see page 22).
If the vent tube is kinked, it should be reshaped prior to use. A kinked vent tube will usually regain its
shape if immersed in boiling water for a few minutes.
2. Fill the battery cells with electrolyte and let stand for 1 or 2 hours. Adjust electrolyte level to the upper
level Iine marked on the battery case.
In cold weather, electrolyte should be brought to room temperature before filling the battery.
21
BATTERIES
J. Charge the battery at one tenth (10%) of its rated ampere·hour capacity for the number of hours shown
in the following chart. For example, a 12 ampere·hour battery that is 6 months old should be charged
at 1.2 amps for 3 hours.
INITIAL CHARGE FOR NEW BATTERIES
Months elapsed
since manufacture"
Less than 12 months
12 to 18 months
18 to 24 months
More than 24 months
Charging hours
3 hours
5 hours
10 hours
15·20 hours
•
•
•
"Date of manufacture is stamped on the
battery case, below gas vent.
NOTE: If the battery seal is missing, or was removed more than one day prior to activation, charge the
battery for 15· 20 hours.
CAUTION: Do not exceed the recommended charging rate (10% cif the battery's ampere·hour ratingl,
and do not allow electrolyte temperature to exceed 1130 F (45 0 C) during the charging process. Excessive
charging ra',e and cell temperature will damage the battery.
•
Electrolyte Level:
Check electrolyte level every week or so. When the electrolyte level becomes low, add water until the
electrolyte reaches the upper level line marked on the battery case. Never allow the electrolyte level to fall
so low as to expose the cell plates, as this can damage the plates.
Water loss is a result of the normal charging process. As the cells approach full charge and cannot utilize
further current for the chemical changes described on page 17, the excess charging current breaks down
electrolyte water into its hydrogen and oxygen components. This can be seen through the transparent
battery case as bubbles rising to the top of the cells. These gases escape through the vent tube. Minute
amounts of acid inadvertently escape through the vent tube as well. The volume of acid lost in this manner
is so small that acid replenishment is never required during the service iife of the battery. However, the vent
tube must be routed so that it does not discharge near the drive chain or other critical parts that are susceptible to acid damage.
It is preferable to use distilled water in the electrolyte solution. Tap water may contain chlorine, iron, and
other elements which would contaminate the electrolyte and reduce its effectiveness.
22
•
•
BATTERIES
r
Battery Vent Tube:
Route the battery vent tube as described in the owner's
manual for your motorcycle model. Correct routing is
also shown on caution labels (Fig. 40 & 41) attached near
the battery area of Honda motorcycles.
OVER·
FLOW
TUBE
•
it is important that the vent tube be routed so it is not
kinked or pinched, and it must be positioned where it
cannot discharge acid fumes and droplets on the drive
chain. If acid contacts the drive chain, premature wear
or breakage may occur (Fig. 42).
BATTERY
BREATHER
TUBE
Fig. 40 Vent Tube Routing Label
(CB·125S)
Check the battery vent tube occasionally to be sure that
it is properly attached and has not become kinked or
pinched. Replace damaged vent tubes.
CARB.
OVER·
FLOW
TUBE
Battery Cleaning:
r
•
•
Inspect battery terminals and the battery mounting box
for signs of corrosion. Clean and repaint the battery box
if signs of corrosion appear. Clean all corrosion from the
battery terminals. Battery terminals can be coated with
petroleum jelly for corrosion protection, but do not
allow petroleum jelly to coat the battery case. A solution
of baking soda (sodium Bicarbonate) and water can be
used to neutralize acid when cleaning the battery and its
mounting box.
BATTERY------~~~/
BREATHER
TUBE
Fig.41 Vent Tube Routing Label (CB·500)
Soapy water (using mild bar soap) is recommended for
general cleaning. If the battery fits tightly in its mount·
ing box, soapy water can also be used to ease installation
and removal. No other cleaning agents should be used.
Some cleaning and lubricating products contain chemicals
which may cause the battery case to weaken or crack.
Aerosols and petroleum base products are especially
harmful.
CAUTION: Cell caps must be installed when cleaning
the battery. Do not allow soap or baking soda to enter
battery cells.
Fig. 42 Drive Chain Damage Caused by
Battery Acid
23
BATTERIES
'ery Storage:
When a battery is not in use, it discharges at an average rate of Y:z% per day. The rate of self-discharge is
greater at warm temperatures and less at cold temperatures.
If your motorcycle is to be stored for only a few weeks, disconnect the negative battery cable to prevent
possible current leakage within the motorcycle's electrical system. Self-discharge will still occur within the
battery, but the amount of discharge will not be substantial over a period of only a few weeks.
If your motorcycle is to be stored for a month or longer, remove the battery from the motorcycle, store it
in a cool, dry location, and recharge it at least once a month. A hydrometer can be used to determine the
battery's state of charge and establish the best recharging intervals. Never allow the battery to stand in a
discharged condition for long periods, or the cell plates will be affected by sulfation. Be sure the battery is
fully charged when it is again placed in service.
Battery Charging Equipment:
•
•
•
Recommended charging current for Honda motorcycle batteries (10% of the battery's ampere-hour capacity) ranges between 0.2 and 2.0 amperes, depending upon the ampere-hour capacity. Most of the inexpen·
sive automotive trickle chargers are not suitable, as they generally deliver a current of one to six amperes.
An excessively high charging cu rrent will damage the battery.
If you are unable to obtain a battery charger with sufficiently small output for your motorcycle battery,
you can modify an automotive battery charger to deliver a suitable charging current by connecting a 12
ohm, 50 watt rheostat and an appropriately calibrated ammeter as shown in Fig. 43.
ADjUst the rheostat to deliver the recommended amperage. Relatively inexpensive rheostats and ammeters
are available from electronics parts supply stores. For a neat, permanent installation, the ammeter and
rheostat can be built into a small box next to the charger, but adequate ventilation must be provided to
cool the rheostat.
•
CHARGER
AMMETER
Fig, 43 Adapting an Automotive Battery Charger For Use With Motorcycle Batteries
24
t
BATTERIES
,
•
•
Battery Safety:
Battery electrolyte contains sulfuric acid. Do not allow electrolyte to contact skin, eyes, or clothing. For
safety, wear eye protection when working with batteries and electrolyte. Keep batteries and electrolyte
out of reach of children.
ANTIDOTE, external: Flush with water. If electrolyte has contacted the eyes, flush with water
and get immediate medical attention.
ANTIDOTE, internal: Drink large quantities of water or milk. Follow with milk of magnesia,
beaten egg, or vegetable oil. C"II a physician immediately.
Editorial Note: Electrolyte has a pungent, sour flavor; it tastes really terrible. We cannot imagine
why anyone would want to drink the contents of their battery, but our legal staff feels than an
antidote should be published in case this might occur anyway. Drinking your battery can be fatal,
or certainly more harmful than eating your saddle, or biting your tires. We watch our legal staff
very closely to be certain they do none of these things, though tire biting is not particularly
harmful unless the motorcycle is in motion.
Batteries produce highly explosive hydrogen gas during the charging process. Be sure the battery vent tube
is unobstructed, and the battery charging area is well ventilated. Keep open flames and sparks away from
the battery. To prevent sparks, switch off or unplug the battery charger when connecting or disconnecting
the batte ry.
When removing the battery from the motorcycle, disconnect the negative cable first. This procedure eliminates the chance of short circuiting the battery if your wrench or screwdriver should touch the motorcycle
frame while loosening the positive cable connection. When installing the battery, connect the negative cable
last.
IGNITION SYSTEMS
•
•
Basically, a motorcycle ignition system consists of a voltage source (battery or A.C. generator), a switching
device to start and stop current flow at predetermined intervals (contact points or an electronic switch),
a step-up transformer to produce high voltage (ignition coil), and the spark plug.
The sole purpose of the ignition system is to produce a spark that will ignite the air-fuel mixture in the
engine's combustion chamber. The spark must be timed to occur at a precise point relative to the compression stroke of the piston.
In order to produce the ignition spark, an electric current must be made to jump the gap between the
spark plug electrodes in the highly pressurized atmosphere of the combustion chamber.
25
IGNITION SYSTEMS
~rical
current produced directly by the battery or AC. generator will not jump the spark plug gap because the electrical pressure (voltage) is too low to overcome such resistance. Thousands of volts are required to make an electrical current jump the spark plug gap. This voltage requirement varies according
to spark plug design, gap width, spark plug condition, and operating factors, but for dependable performance, the ignition coil should be capable of producing at least 15,000 volts.
E"
Low voltage current, produced by the battery or AC. generator, flows to the ignition coil at intervals
determined by the contact points (or electronic switch) and is transformed by the ignition coil into high
voltage current which jumps the spark plug gap.
Ignition systems in use on various motorcycles differ primarily in regard to the voltage source, battery or
A.C. generator, which in turn affects the specific design of other ignition components. Other differences
concern the method chosen for inducing high voltage and whether the system incorporates electronic
circuitry.
•
•
•
As we have seen in preceding sections of this manual, motorcycle batteries produce a nominal 6 or 12 volts
of direct current, while AC. generators produce alternating current. AC. generator voltage is determined
by the number of windings, strength of magnetic field, and engine rpm (see page 8), though for ignition
purposes, generator voltage is in a relatively low range and must be transformed into high voltage before it
goes to the spark plug.
An A.C. generator that serves as the voltage source for ignition is commonly called a magneto, and ignition
s
ms are normally classified as being either "battery" or "magneto". In motorcycles without lighting
equipment or batteries, the A.C. generator may function solely as a magneto. In other models one AC.
generator coil may be used for magneto functions, while another coil, or coils, within the same AC. generator may provide lighting and battery charging current.
•
Magnetos can be classified as being "high tension", "low tension", or "energy transfer".
A high tension magneto (page 29) incorporates the function of an ignition coil within the magneto windings. High voltage is induced in the magneto secondary windings by a rapid collapse of the magnetic field
surrounding the magneto primary windings. The high voltage so induced is sent directly to the spark plug.
No separate ignition coil is used.
A low tension magneto (page 30) is essentially a high tension magneto without integral secondary windings.
The contact points are connected in series with the primary windings of a separate ignition coil.
An energy transfer system (page 31) is similar to a low tension magneto system, except that the contact
points are connected in parallel with the AC. generator windings. High voltage is induced in the secondary
windings of a separate ignition coil upon the rapid build-up of the magnetic field surrounding the ignition
coil primary windings.
(
26
-
IGNITION SYSTEMS
r
•
Some technical publications treat the energy transfer system as a separate category apart from battery or
magneto systems. Some publications, including the one you are now reading, classify the energy transfer
system as another kind of magneto, since it obviously isn't a battery system. Still other publications, including manuals by the U.S. Department of Transportation, do not use the term "energy transfer" at all,
considering it to be merely a variant of the low tension magneto system. Different usage of the term "magneto" and different categorization of the term "energy transfer" create much confusion. It is unusual for
any two technical publications to use these terms in the same way.
Honda motorcycles are equipped with either battery ignition systems or energy transfer systems. The high
tension magneto system and the low tension magneto system are sometimes encountered on motorcycles of
other manufacture, but not Honda. Therefore, if you hear or read the term "magneto" used in reference to
Honda motorcycles, it necessarily refers to the energy transfer system. All types of ignition systems;
battery, high tension magneto, low tension magneto, and energy transfer, may be encountered on Honda
Power Products.
Battery Ign ition:
The battery ignition system used in Honda motorcycles is illustrated in Fig. 44. This illustration is
simplified to clearly show how the basic system functions. Actual connections and circuit paths for specific
models may not conform exactly to Fig. 44 but are shown in shop manuals for the individual models.
r
G)
@
@
@)
®
®
o
®
®
•
•
BATTERY
FUSE
IGNITION SWITCH
COIL PRIMARY
WINOINGS
CAPACITOR
CONTACT POINTS
CD
CONTACT POINT
CAM
COIL SECONOARY
WINDINGS
SPARK PLUG
Fig. 44 Battery Ignition System
CD
®'
(2)
G)
and runs through fuse
,ignition switch
The primary ignition circuit starts at the battery
coil primary windings
contact points
and to ground, completing the primary circuit. A capacitor
(also called a condenser) is connected at a point between the coil primary windings and the contact points. The other end of the capacitor is grounded.
@ ,
®
The second"f:!.- ignition. circuit starts in the ignition coil secondary windings
spark plug
to ground, completing the secondary circuit.
®
®
and runs through the
27
IGNITION SYSTEMS
®
'le contact points
(page 27) are connected in series with the primary circuit. When the ignition
_",itch
is turned on, the contact points open and close the primary circu it as the contact J?:!2.int cam
rotates. While the contact POints are closed, current flows through the primary windings ~ of the
ignition coli, establishing a magnetic field. When the contact POints open, the CirCUit IS broken, and the
magnetic field rapidly collapses, inducing current in the secondary coil windings
Isee Induction, page
(2)
0
®
81.
The induced secondary current jumps the spark plug gap, creating the spark to ignite the air·fuel mixture
in the cylinder. Secondary voltage is far greater than voltage through the primary circuit because there is a
far greater number of secondary coil windings than primary windings. One of the principles of induction,
stated on page 8, is that the strength of induced voltage is partly determined by the number of windings
which cut the magnetic field.
As the contact points open, the effect of the collapsing magnetic field in the ignition coil also creates some
Ipage 271 absorbs this voltage surge and thus helps
voltage surge in the primary circuit. The capacitor
to prevent the contact points from arcing as they separate.
®
•
•
•
The contact points must be prevented from arcing for two reasons. Firstly, arcing causes the contact points
to become pitted and burnt, greatly reducing their service life. Secondly, arcing allows the primary current
to continue to flow for an instant after the points start to open, thus decreasing the speed with which the
coil's magnetic field collapses and decreasing the induced voltage in the secondary windings. The use of a
capacitor allows the primary circuit to be broken with a minimum of arcing to extend contact point service
life and hasten the collapse of the coil's magnetic field.
Incidentally, the ignition coil steps down amperage by the same ratio that it steps up voltage. High voltage
lelectrical pressure) is required to jump .the spark plug gap, but amperage is of little consequence in this
lplication. If you inadvertently touch an uninsulated spark plug terminal while the engine is running, the
nigh voltage shock will make you flinch, but unless you have a heart condition, the amperage (current flow)
is too low to really harm you.
•
There are several models of Honda motorcycle in which a single
ignition coil is used to fire two spark plugs. This is achieved by
connecting a spark plug to each end of the ignition coil's secondary windings, as shown in Fig. 45. In this hook·up, both spark
plugs are wired in series with the secondary coil windings, and
both plugs fire simultaneously.
Fig. 45 Single Ignition Coil Firing
Two Spark Plugs
28
Where two spark plugs are fired by a single coil, the plugs are used
in cylinders whose firing order is 360 0 apart. Thus, one spark plug
will fire while its cylinder is near the top of its compression stroke,
and the other spark plug will fire simultaneously while its cylinder
is near the top of its exhaust stroke. Spark plugs connected in this
manner fire twice as often as necessary (no purpose is served by
firing on the exhaust stroke!. but th is design greatly simplifies the
ignition system, eliminating the need for a distributor, or for
additional sets of contact points, capacitors, and coils for each
cylinder.
•
•
,
•
•
IGNITION SYSTEMS
High Tension Magneto Ignition:
The high tension magneto system does not use a separate ignition coil. High voltage is induced in the mag·
neto secondary windings by the collapsing magnetic field that surrounds the magneto primary windings.
All magneto systems operate without a battery, or independent of the battery if one is provided for other
electrical functions.
CD
@
MAGNETO ROTOR
MAGNETO PRIMARY
@
@;
CAPACITOR
®
®
CD
WINDINGS
ENGINE STOP SWITCH
CONTACT POINTS
CONTACT POINT CAM
(7)
MAGNETOSECQNDARY
®
SPARK PLUG
°1
WINDINGS
,
--
CDr-
-
Fig. 46 High Tension Magneto Ignition System
®
Between firing impulses, the contact points
remain closed, completing the primary circuit. As the
magneto rotor G) spins, alternating current is induced in the magneto primary windings
,the same
as in any A.C. generator (see A.C. Generator Operation, page 81. Magnetic lines of force are built up, collapsed, and then built up again in the opposite direction.
As the magnetic field in the primary circuit collapses, current is induced in the magneto secondary windings. However, if the primary circuit were operated as a simple A.C. generator, the collapse would not be
sufficiently rapid to induce usable ignition voltage, so the contact point cam
is timed to open the con·
tact points
just as the magnetic field collapses. Opening the contact points breaks the primary circuit,
hastening the collapse of the magnetic field. Rapid collapse of the magnetic field induces high voltage in
the magneto secondary windings
which flows through the spark plug
The capacitor 8) pro·
tects the contact points and helps to hasten the collapse of the magnetic field, as in other ignition systems.
®
®
•
•
,
0
(j)
®.
When the engine stop switch @ is closed, the contact points have no effect. The primary circuit remains
unbroken, and the magneti'c field will not collapse rapidly enough to induce ignition voltage.
29
IGNITION SYSTEMS
w Tension Magneto Ignition:
•
The low tension magneto system uses a separate ignition coil to induce high voltage. Operation is otherwise
similar to the high tension magneto system described on page 29. Note that the contact points in both high
and low tension magneto systems are connected in series with the primary circuit, as opposed to the energy
transfer system (page 31) in which the contact points are connected in parallel with the primary circuit.
CD
MAGNETO ROTOR
@
MAGNETO
WINOINGS
@
ENGINE STOP
SWITCH
@
COIL PRIMARY
®
®
•
•
2
,
WINDINGS
CAPACITOR
CONTACT POINTS
G)
CONTACT POINT
CAM
®
®
COIL SECONDARY
WINDINGS
0
@>
- - CD
-
SPARK PLUG
CD
-
-
Fig. 47 Low Tension Magneto Ignition S\LStem
The contact points
®
•
close to complete the primary circuit. The magneto rotor
current in the magneto windings
(3)
G)
spins, inducing
CD
which flows through the ignition coil primary windings
,es-
tablishing a magnetic field in the ignition coil.
Because the magneto is an A.C. generator, current flow will reverse direction as the rotor
G)
spins. Re-
versal of current flow collapses the magnetic field in the ignition coil, but does not collapse it rapidly
enough to induce usable ignition voltage. The contact point cam
rotor
G)
to open the contact points
®
(j)
is synchronized with the magneto
at this time, breaking the primary circuit and hastening the
collapse of the magnetic field in the ignition coil. Rapid collapse of the magnetic field induces high voltage
®
in the coil secondary windings
which flows through the spark plug
the contact points and helps to hasten the collapse of the magnetic field.
The engine stop switch
30
0
® _The capacitor ®
can be ~Iosed to short circuit the magneto, stopping the engine.
protects
•
•
•
IGNITION SYSTEMS
Energy Transfer Ignition:
(
•
Operation of the energy transfer system differs from the low tension magneto system by having contact
points connected in parallel with the primary circuit and contact point timing which results in secondary
voltage being induced by the rapid build-up of a magnetic field_ Note that battery ignition systems, high
tension magneto ignition systems, and low tension magneto systems all induce secondary voltage by the
rapid collapse of a magnetic field, while the energy transfer system induces secondary voltage by the rapid
build-up of a magnetic field.
The term "energy transfer" is a misnomer for the circuit shown in Fig. 48. However, application of the
term to this circuit is justified by common use and serves to distinguish this circuit from other magneto
ignition circuits.
CD
MAGNETO
ROTOR
(3)
MAGNETO
WINOINGS
@
ENGINE STOP
SWITCH
0
®
CAPACITOR
®
CONTACT
(f)
COIL
PRIMARY
WINDINGS
®
COIL
SECONDARY
WINDINGS
®
SPARK PLUG
CONTACT
POINTS
POINT CAM
-
Fig. 48 Energy Transfer Ignition System
Primary voltage is supplied by the magneto or A.C. generator (whichever term you prefer). Between firing
impulses, the contact points
remain closed, short circuiting all current produced by the magneto.
Thus, no current energizes the ignition coil primary windings
The same effect can be obtained
manually by closing the engine stop switch
®
•
@ .
®
(j) .
CD
The contact point cam
is synchronized with the magneto rotor
to open the contact points
when the magneto's output wave (see Fig. 23, page 10) is at or near its peak. When magneto output reaches its peak and the contact points
open, a surge of current flows through the ignition coil
primary windings
causing rapid build-up of a magnetic field which induces high voltage in the ignition coil secondary windings
The high voltage so induced then flows through the spark plug
The capacitor
protects the contact points and enables them to break the circuit quickly with
a minimum of arcing.
®
(j) ,
® .
0
®
®.
,,,..
.
31
IGNITION SYSTEMS
lacitor Discharge Ignition (COl I:
A capacitor has the ability to temporarily store and quickly discharge electrical energy. Any ignition system
which discharges a capacitor into the primary windings of the ignition coil for the purpose of inducing
secondary voltage is, by definition, capacitor discharge ignition. Capacitor discharge ignition comes in many
forms and may be incorporated in either battery or magneto systems.
Some systems use a battery as the primary voltage source, but send battery voltage through a converter
before it reaches the capacitor, the idea being to produce higher voltage than would otherwise be possible.
Some systems use a magneto as the primary voltage source to charge the capacitor, and the capacitor discharges whatever magneto voltage it received.
In any case, capacitor discharge ignition customarily uses an electronic switch to trigger the capacitor instead of contact points. Tune-ups are greatly simplified when there are no contact points to adjust or replace. Fig_ 49 is a simplified illustration of the capacitor discharge ignition system used on the Honda CR125M.
CD
EXCITER
WINDINGS
@
TRIGGER
WINDINGS
@
C.D.I. UNIT
®
®
CD
A.C_ GENERATOR
@
•
•
•
•
DIODE
CAPACITOR
CD
ELECTRONiC
SWITCH
®
COl L PR 'MARY
®
COIL SECONDARY
WINDINGS
@
SPARK PLUG
WINDINGS
-
Fig. 49 Capacitor Discharge Ignition System (Honda CR-125MI
CD
(3)
Exciter windings
in the generator
produce alternating current. The positive half of the A.C.
wave ~e Alternating Current Wave Form, page 10, Fig. 23) passes through the diode
in the C.D.1.
unit ~ to charge the capacitor
Because the diode allows current to pass in only one direction, the
capacitor is prevented from discharging through the magneto during the negative half of the magneto's
A.C. wave.
®
®.
®
CD
Alternating current induced in the trigger windings
of the generator
are used to open and close
the electronic switch
in the C.D.1. unit
(the electronic switch circuit is considerably more com·
plicated than is shown in Fig. 49).
0
J2
8)
•
t
,
IGNITION SYSTEMS
(j)
The electronic switch
(page 321 is opened while the magneto charges the capacitor, When the electronic switch closes, this completes a circuit, grounding one end of the capacitor through the switch, while
the other end is grounded through the ignition coil primary windings
The capacitor then discharges
through the ignition coil primary windings, causing the rapid build-up of a magnetic field which induces
high voltage in the ignition coil s~ndary windings
High voltage induced in the secondary wind·
ings flows through the spark plug @
® .
® .
Ignition Advance:
•
The ignition spark must be timed to ignite the air-fuel mixture in the cylinder as the piston nears the end
of its compression stroke. Timing must be precise in order to obtain maximum power and fuel economy.
Optimum ignition timing is determined mainly by such factors as engine rpm, fuel quality, air-fuel mixture
ratio, and combustion chamber design. Engine 3peed determines the time available to complete combustion
in relation to piston position. Fuel quality, air-fuel mixture ratio, and combustion chamber design affect
the speed with which combustion can occur,
Combustion in the engine cylinder is not instantaneous. Ignition must occur before the end of the compression stroke in order for combustion to be completed in time to drive the piston downward on the
power stroke.
,.
At idling speed, ignition can be timed to occur quit~ late in the compression stroke, because there is ample
time for combustion to be completed as the piston starts its power stroke. At high speeds, ignition must
occur earlier during the compression stroke.
If ignition occurs too early during the compression stroke, combustion will be completed before the piston
reaches its top dead center position. The piston is then forced to move upward against extremely high
pressure. If flywheel momentum cannot overcome the pressure against the piston, the engine will stall, or
kick backward when being started. Excessive ignition advance will result in overheating and loss of power.
The air-fuel mixture may also detonate with an audible knock. The piston may become damaged by overheating and detonation.
If ignition occurs too late, combustion will not be completed until the piston has travelled downward on
its power stroke. This reduces the pressure which propels the piston and power is lost.
If ignition is retarded still farther, combustion may not be completed at the start of the exhaust stroke, and
the air-fuel mixture will be discharged into the exhaust port while still burning intensely. This will cause
overheating, and in four-stroke engines may burn the exhaust valve.
'.
•
Most motorcycles are equipped with a device which automatically advances ignition timing as engine rpm
increases. An automatic ignition advance (Fig. 50 & 51) is used on Honda motorcycles equipped with battery ignition systems and on some Honda models equipped with energy transfer systems.
Some motorcycles, especially mini-bikes and dirt bikes using the energy transfer system, have fixed ignition timing; no automatic; advance mechanism is provided_ These motorcycles have their ignition timing
set permanently in an advanced position, so that timing will be most nearly correct when the engine is
running at medium or high speeds.
33
IGNITION SYSTEMS
Centrifugal Ignition Advance Operation;
The centrifugal ignition advance unit (Fig. 50) rotates
with the contact point cam and is driven by the
RETURN SPRING
ADVANCE WEIGHT
engine camshaft or crankshaft. Fig. 51 shows an ignition advance unit installed on the end of the camshaft. Centrifugally controlled weights in the advance
CONTACT POINT CAM
unit regulate the position of the contact point cam
relative to the camshaft and crankshaft.
Fig. 50 Ignition Advance Unit
At idle speed, the weights are held inward by spring
tension, and the cam is positioned to open the con-
•
•
•
tact points near the end of the compression stroke
(usually 50 to 150 before top dead center, depend·
ing on model design). At idle speed, there is ample
time for combustion to be well undervJay before the
piston moves down on its power stroke, and a minimal advance promotes smooth idling and prevents
kick-back during starting.
As engine speed increases, the advance weights fly
outward by centrifugal force, rotating the contact
point cam ahead. In the advanced position, the cam
•
opens the contact points earlier during the com·
pression stroke (usually 25 0 to 45 0 before top dead
center, depending on model design).
Capacitor discharge ignition systems do not have
contact points and therefore cannot use a mechanical advance unit. Electronic ignition advance can be
provided by taking advantage of the fact that in·
creased rpm induces greater voltage in the trigger
Fig. 51 Engine Cross Section (Honda CB-450l
Showing Ignition Advance Unit Installed
34
windings, which in turn controls the electronic switch
that discharge the capacitor.
f
•
t
IGNITION SYSTEMS
•
•
Dwell Angle and Contact Point Gap Adjustment:
8)
Dwell angle
is the distance Imeasured in degrees or in percent of one full revolution) which the contact point cam
rotates while the contact points
are closed, Increasing dwell angle causes the
contact points to be closed for a longer duration and open for a shorter duration, Decreasing dwell angle
has the opposite result, For every ignition system design, there is a specific dwell angle range in which the
system operates most effectively,
CD
0
®
CD
®
®
(2)
@
G)
CONTACT POINTS
CONTACT POINT GAP
CONTACT POINT CAM
CAM ROTATION WHilE CONTACT
POINTS ARE CLOSED (DWELL ANGLE I
POSITION OF CAM LOBE APEX WHEN
CONTACT POINTS START TO OPEN
CAM ROTATION WHilE CONTACT
POINTS ARE OPEN
POSITION OF CAM LOBE APEX
WHEN CONTACT POINTS FUll Y CLOSE
•
Fig. 52 Contact Points and Single lobed Cam
CD
(3)
Contact point gap adjustment controls dwell angle, Increasing contact point gap
(measured with contact points in the fully opened position) decreases dwell angle. Decreasing the gap increases dwell angle.
'.
•
If possible, adjust contact point gap using a dwell meter, If you do not have a dwell meter, or if no dwell
specification is available, then adjust contact point gap using a wire clearance gauge.
A wire gauge will measure contact point gap more accurately than a flat gauge, if the contact point surfaces
have any irregularities due to wear or pitting. Slight wear, corrosion, or pitting can be corrected by dressing
the contact points with a contact point file, Badly worn or pitted contact points should be replaced. Severe
pitting indicates a faulty capacitor (condenser) which should also be replaced. While servicing the contact
points, also lubricate the contact point cam with a thin film of grease.
The recommended contact point gap for Honda motorcycles is 0.3 - OAmm (0.012 - 0.016 in.), measured
with contact points in the fully opened position. If the contact points are in good condition, this clearance
will usually produce an a'cceptable dwell angle.
35
IGNITION SYSTEMS
,ition Timing Adjustment:
Q)
Ignition timing can be adjusted by widening or narrowing the contact point gap
,or by repositioning
the contact points
relative to the contact point cam
With Honda motorcycles using capacitor
discharge ignition, timing is adjusted by repositioning the magneto stator relative to the rotor.
CD
0) .
CD
o
®
o
®
CONTACT POINTS
CONTACTPOINTGAP
CONTACT POINT CAM
CONTACT POINT RUBBING BLOCK
CONTACT POINT BASE PLATE
Fig. 53 Ignition Advance Adjustment
0
,~hen the contact point gap
is widened, the cam lobe
contacts the rubbing block
earlier
in its rotation (timing is advanced). and the cam lobe stays in contact with the rubbing block longer Idwell
angle is decreased). Conversely, narrowing the contact point gap retards timing and increases dwell angle.
0)
®
8)
•
•
•
•
is moved in the opposite direction of contact point cam rotation,
When the contact point base plate
the cam lobe
contacts the rubbing block
earlier in its rotation, and timing is advanced. Conversely,
moving the contact point base plate in the same direcrion as contact point cam rotation will retard timing.
0)
8)
Ignition timing adjustment for some motorcycle models is accomplished solely by varying the contact point
gap. For some models, adjustment is accomplished solely by moving the contact point base plate. Some
other models require a combination of both procedures to adjust ignition timing.
When altering the ignition point gap for the purpose of adjusting ignition timing, do not exceed the recom·
mended dwell angle range. If you measure contact point gap instead of dwell angle, then do not set the gap
narrower than 0.3mm (0.012 in.) Or wider than O.4mm (0.016 in.). If correct ignition timing cannot be
achieved within the specified dwell angle or gap range, then replace the contact points.
36
•
•
f
s
IGNITION SYSTEMS
For greatest accuracy, use a stroboscopic timing
light, so you can adjust ignition timing with the
engine running (Fig. 541. On models equipped with
automatic ignition advance, a stroboscopic timing
light is essential for checking full advance timing.
•
I f you
will be
engine
device.
do not have a stroboscopic timing light, it
necessary to check ignition timing with the
stopped, using a continuity light or similar
This method is called searie timing.
If the motorcycle has a battery /gmt/on system, a
simple continuity light can be connected in parallel with the contact points to check static timing.
(Fig. 551. With the ignition switch and engine switch
on, turn the crankshaft slowly, and the bulb will
light when the contact points open. A continuity
light can be easily constructed, using a 6 or 12 volt
(depending on the motorcycle's battery voltage!, 3
watt bulb or one of the bulbs from the motorcycle's
instrument lights.
If the motorcycle has an energy transfer system,
the simple continuity light shown in Fig. 55 will
not work, no matter whether ·the motorcycle is
battery equipped or not. For static timing with an
energy transfer system, it is necessary to disconnect
the contact point lead from the motorcycle's electrical system and connect a self-powered continuity
light in series with the contact points (Fig. 56).
With this hook·up, the bulb will light when the
contact points close. A self·powered continuity
light can also be used to check battery ignirion
system timing, if the contact point leads are disconnected.
•
•
Some mechanics prefer to use a buzzer rather than
a light. Self·powered "buzz boxes" are commer·
cially available for this purpose. As an inexpen·
sive alternative, a child's toy telegraph set can be
hooked-up to light, buzz, or click when the contact
points close. A VOM or ohmmeter can also be
used to determine when the contact points open
and close.
CD
o
STROBOSCOPIC TIMING LIGHT
DWELL METER
------------
Fig. 54 Checking Ignition Timing and Dwell
Angle, Using a Stroboscopic Timing
Light and Dwell Meter with Engine
Running
Fig. 55 Checking Static Ignition Timing with a
Simple Continuity Light (for battery
ignition systems only)
--
Fig. 56 Checking Static Ignition Timing with a
Self·Powered Continuity Light
'~
31
IGNITION SYSTEMS
lition Timing Marks:
•
Honda single cylinder and twin cylinder models have timing marks stamped on the generator rotor (see Fig.
57,59,61 on following pages). Honda four cylinder air-cooled models have timing marks on the ignition
advance assembly (see Fig. 63, page 41). The Honda G L-1 000 has timing marks on the edge of the flywheel
(see Fig. 65, page 42).
•
Timing marks are lettered "T" for top dead center piston position and "F" for ignition firing position at
idle speed. The "F" mark is also used to indicate the static timing position. All Honda motorcycle engines
equipped with automatic ignition advance have additional marks which indicate ignition full advance position (see Fig. 57,59,61,63,65 on following pages).
•
Twin cylinder engines with 1800 crankshafts le.g. CB-360T, CB-500T) have two sets of timing marks.
Timing marks for the right cylinder (as viewed from the rider's position) are designated "T" and "F", while
timing marks for the left cylinder are designated "LT" and "LF".
Four cylinder air-cooled engines have two sets of timing marks, "T, F, 1.4" and "T, F, 2.3", which are
referenced to cylinder numbers and contact point assemb:ies. The GL-1000 has two sets of timing marks,
"1-T-F" and "2-T-F", which are referenced to contact point assemblies only and not to cylinder numbers.
Procedure for Adjusting Contact Point Gap and Ignition Timing on Honda Single Cylinder Engines Without
Adjustable Contact Point Base Plate;
G)
CONTACT POINT LOCKING SCREW
(])
TIMING INDEX MARK
®
"F"MARK
@
FULL ADVANCE MARKS
1. Check ignition timing. I f adjustment is required, loosen
contact point locking screw G) (Fig. 57). Adjust contact point gap to achieve correct timing. Retighten locking screw. Recheck timing after locking screw is tightened.
Idle or static timing is correct if contact points open
when index mark
aligns with rotor "F" mark
Most Honda models Without an adjustable base
plate also have no automatic ignition advance mechanism, and the "F" mark is used for timing at any rpm.
I f the motorcycle does have an automatic ignition advance mechanism, high rpm timing is correct if contact
points open when index mark
is between full advance marks
(3)
(2)
@ .
Fig. 57 Contact Points and Ignition
Timing Marks - Honda Single
Cylinder Engine Without
Adjustable Base Plate
•
(3)
NOTE; Full advance timing is more impr.rtant to performance than idle timing. I f the motorcycle is
equipped with an automatic ignition advance, adjust
•
•
c
IGNITION SYSTEMS
contact point gap to achieve correct full advance timing for
best results. If correct full advance timing causes idle timing
I
I
CONTACT POINT LOCKING SCREWS
BASE PLATE LOCKING SCREWS
to be substantially incorrect, then replace the ignition advance mechanism.
2. Check dwell angle or contact point gap (see page 35). If
dwell angle is not within limits specified in the shop manual,
or if contact point gap is not with in a range or 0.3 . O.4mm
(0.012 - 0.016 in. I, then replace the contact points and repeat step one.
Procedure for Adjusting Contact Point Gap and Ignition Timing
on Honda Single and Twin Cylinder Engines Having One Set of
Contact Points and an Adjustable Contact Point Base Plate:
Fig. 58 Contact Point Assembly Honda Single Cylinder Engine
With Adjustable Base Plate
1. Check dwell angle or contact point gap. If adjustment is
•
required, loosen contact point locking screws
CD
(Fig.
~
TIMING INDEX MARK
58). Adjust contact point gap to achieve the dwell angle
@:
"F" MARK
specified in the shop manual, or adjust gap to 0.3 - O.4mm
1:
FUll ADVANCE MARKS
(0.012 - 0.016 in.). Tighten locking screws. Recheck dwell
angle or gap after locking screws are tightened.
2_ Check ignition timing. If adjustment is required, loosen base
plate locking screws
(3) .
Rotate base plate to achieve
correct ignition timing. Tighten locking screws. Recheck
dwell angle or gap, and timing, after locking screws are
tightened .
•
Idle or static tlmJng is correct if contact points open when
index mark
G)
(Fig. 59) aligns with rotor "F" mark
8)
High rpm timing is correct if contact points open when index
mark
G)
is between full -advance marks
®.
Fig. 59 Ignition Timing Marks
(Honda CT-90 shown here)
39
IGNITION SYSTEMS
r'rocedure for Adjusting Contact Point Gap and Ignition Timing on Honda Twin Cylinder Engines Having
two Sets of Contact Points:
CD
CONTACT POINT LOCKING SCREWS
@
BASE PLATE LOCKING SCREWS
1. Check dwell angle or contact point gap. If adjustment is
required, loosen contact point locking screws
CD . (Fig.
60). Adjust both left and right contact point gaps to achieve
the dwell angle specified in the shop manual, or adjust gap
to 0.3 - OAmm (0.012 - 0.016 in.). Tighten locking screws.
Recheck dwell angle or gap after locking screws are tightened.
•
•
•
2. Check both left and right cylinder ignition timing. Left cylinder idle or static timing is correct if the left contact points
Fig. 60 Contact Point Assembly Honda Twin Cylinder Engine
Having Two Sets of Contact
Points
open when index mark
®
®
(Fig. 61) aligns with rotor "LF"
0 . Right cylinder timing is correct if the right contact points open when index mark 0 aligns with rotor "F"
mark
mark
@
@)
(1)
® . High rpm timing is correct if left and right con-
TIMING INOEX MARK
tact points open when index mark
"LF" MARK
advance marks
®.
(1)
is between the full
""'MARK
FULL AOVANCE MARKS
3. If both left and right contact points open before or after the
•
timing marks align, loosen the base plate locking screws
o
(F ig. 60). and rotate the base plate to ach ieve correct
timing. Retighten the base plate locking screws. Recheck
dwell angle or gap. and timing, after locking screws are
tightened.
4. If onlv one set of contact points is not correctly timed, readjust contact point gap to synchronize the timing for both
cylinders. Increase gap to advance timing or decrease gap to
retard timing. Contact point gap must not exceed the specified dwell angle or gap range. If correct ignition tlmrng
Fig.61 Ignition Timing Marks
(Honda CB-360T shown here)
40
cannot be achieved within the specified dwell angle or gap
range, replace the contact points.
•
•
•
<
IGNITION SYSTEMS
Procedure for Adjusting Contact Point Gap and Ignition Timing on Honda Four Cylinder Air-Cooled
Engines:
•
•
1. Check dwell angle or contact point gap. If adjustment is required, loosen contact point locking screws
(Fig. 621. Adjust both #1/#4 and #2/#3
contact point gaps to achieve the dwell angle specified in the shop manual, or adjust gap to 0.3 - O.4mm
(0.012 - 0.016 in. I. Tighten locking screws. Recheck
dwell angle or gap after locking screws are tightened.
CD
CD
CONTACT POINT LOCKING SCREWS
@
MAIN BASE PLATE LOCKING SCREWS
o
#2/#3 BASE PLATE LOCKING SCREWS
2. Check ignition timing for #1/#4 cylinders (cylinders
are numbered from left to right as viewed from the
rider's position). If adjustment is required, loosen
Rotate main
main base plate locking screws
base plate to achieve correct timing. Tighten locking
screws. Recheck dwell angle or gap, and timing, after
locking screws are tightened.
CD
r
Idle or static timing for # 1/#4 cylinders is correct if
#1/#4 (left) contact points open when index mark
(Fig. 64) aligns with "F 1.4" mark
High
rpm timing is correct if left contact points open when
index mark
is between #1/#4 full advance
marks
®
® .
® .
®
3. Check ignition timing for #2/#3 cylinders. If adjustment is required, loosen #2/#3 base plate locking
screws @
Rotate #2/#3 base plate to achieve
••
•
Fig. 62 Contact Point Assembly Honda Four Cylinder
Air-Cooilld Engine
o
TIMING INDEX MARK
® "F"' ' ..··MARK
® """. FULL ADVANCE MARK
correct ignition timing. Tighten locking screws. Recheck #2/#3 dwell angle or gap, and timing, after
locking screws are tightened .
Idle or static timing for #2/#3 cylinders is correct if
#2/#3 (right) contact points open when index mark
aligns with "F 2-3" mark (not illustrated).
®
High rpm timing is correct if right contact points
open when index mark
is between #2/#3 full
advance marks.
®
Fig. 63 Ignition Timing Marks
(Honda CB·550 shown here)
,
if>
41
IGNITION SYSTEMS
rocedure for Adjusting Contact Point Gap and Ignition Timing on the Honda GL·1000:
G)
CONTACT POINT LOCKING
SCREWS
(3)
MAIN BASE PLATE LOCKING
SCREWS
@
#3/#4 BASE PLATE LOCKING
SCREWS
1. Check dwell
angle or contact point gap. If adjustment is
G)
required, loosen contact point locking screws
(Fig. 641.
Adjust both contact point gaps to achieve the dwell angle specified in the shop manual, or adjust gap to 0.3 - O.4mm (0.0120.016 in.). Tighten locking screws. Recheck dwell angle or gap
after locking screws are tightened.
2. Check
ignition timing for #1/#2 cylinders (cylinders are
= right
numbered as follows: # 1
2
right rear; =4
= left rear).
front; #2
= left
front; #3
=
•
•
•
If adjustment is required, loosen main
base plate locking screws
0 . Rotate
main base plate to
achieve correct ignition timing. Tighten locking screws. Recheck
dwell angle or gap, and timing, after locking screws are tighten·
Fig. 64 Contact Point Assembly Honda GL·1000
ed.
Idle or static tIming for #1/#2 cylinders is correct if #1/#2
@
®
®
TIMING INDEX MARK
(left) contact points open when index mark
"F"' MARK'
aligns with "l·F" mark
FULL ADVANCE MARK'
• Numeral "," or "2" (not visible in
illustration) follows "F" and "T"
marks to distinguish #1/#2 cylinder
timing marks from #3/#4 cylinder
timing marks.
® . High
® .
(Fig. 65)
rpm timing is correct if
left contact points open when index mark
advance mark
0
0
aligns with full
•
3. Check ignition timing for #3/#4 cylinders. If adjustment is required, loosen #3/#4 base plate locking screws
(1) . Rotate
#3/#4 base plate to achieve correct ignition timing. Tighten
locking screws. Recheck #3/#4 dwell angle or gap, and timing,
after locking screws are tightened.
Idle or static timing for #3/#4 cylinders is correct if #3/#4
(rightl contact points open when index mark
"2-F" mark
Fig. 65 Ignition Timing Marks Honda GL-1000
42
® . High
®.
aligns with
rpm timing is correct if right contact
points open when index mark
mark
0
0
aligns with full advance
•
•
•
•
IGNITION SYSTEMS
Spark PI ugs:
c
•
Fig. 66 shows the cross section of a typical spark plug.
The spark plug provides an electrode gap inside the com·
bustion chamber where a spark will ignite the air-fuel
mixture. The insulator
is sealed to the center elec·
trode
and shell
to prevent the escape of combustion gases through the spark plug. A gasket
under the shoulder of the shell prevents the escape of
combustion gases between the spark plug and cylinder
head.
@
0
®
et
~
~
®
®
TERMINAL
INSULATOR
REACH ITHREAO
LENGTH)
CENTER ELECTRODE
1)
ELECTRODE GAP
SHELL
®
®
SIDE ELECTRODE
GASKET
THREAD DIAMETER
Spark plugs are manufactured in standard sizes which
are classified in terms of thread diameter
and
reach
(Fig. 66 & 67). Reach is the distance from
the shoulder of the shell to its threaded end. Gasket
thickness is not included in the reach measurement.
These spark plug dimensions must match the corresponding cylinder head dimensions of the motorcycle.
For example, a Honda CB-750 requires spark plugs with
a 12mm thread diameter and 19mm (% in.) reach.
Various Honda models use spark plugs of lOmm,. 12mm,
or 14mm thread diameter and 12.7mm (V, in.) or 19mm
(% in.) reach.
®
•
•
®
Ii'
®
I f the spark plug does not have the correct thread diam·
eter, then obviously it cannot be installed. If the reach
is too long, the spark plug will protrude into the combustion chamber where it may overheat, possibly interfere with piston or valve movement, and carbon de·
posits will accumulate on spark plug threads making
removal difficult. If the reach is too short, the spark
will occur in the cavity of the spark plug well where
it will be less effective, and carbon deposits will ac·
cumulate on cylinder head threads impeding installation of the correct reach.
The service life of a sprak 'plug varies with factors of
operating conditions, type and grade of fuel, com·
pression ratio, etc. Spark plugs should be inspected,
cleaned and regapped, or replaced, in accordance with
the maintenance schedule in the owner's manual.
Fig.66 Spark Plug Cross Section
CORRECT
LONG
SHORT
Fig.67 Spark Plug Reach
(~
43
IGNITION SYSTEMS
(j)
CD
®
,he gap
between center electrode
and side electrode
(Fig. 66, page 43) must be wide
enough to produce a good spark, but not so wide that the ignition coil cannot produce enough voltage to
jump the gap. The gap widens with use due to electrode erosion from heat and chemical action. Spark plug
voltage requirements increase as the gap widens.
Carbon and chemical deposits on the insulator nose also increase voltage requirements. These deposits con·
duct electricity and allow some of the current to leak across the insulator nose instead of jumping the elec·
trode gap. Electrode wear and deposits on the insulator nose eventually raise voltage requirements to a
point where the ignition coil has an insufficient voltage reserve, resulting in loss of spark intensity, and ultimately causing misfiring.
Spark plugs with high mileage may also develop insulator cracks or gas leakage between the insulator and
shell. Regapping and cleaning will help to extend spark plug service life, but the plugs must eventually be reo
placed.
•
•
•
Before removing a spark plug, clean the area around the base of the plug to prevent dirt or debris from
falling into the combustion chamber through the open spark plug well. Inspect the spark plug for excessive
electrode wear, insulator cracks, or signs of gas leakage (gray stains on the outside of the insulator near the
top of the shell). If these conditions are found to exist, discard the spark plug. Inspect the insu:ator nose
und electrodes for signs of fouling or overheating (see Spark Plug Heat Range, page 45). If the spark plug
appears to be reusable, clean and regap the plug.
Com'flercial sandblast spark plug cleaners remove fouling deposits quite well. If you do not have access to
'uch a device, it is possible to achieve some improvement by picking off encrusted deposits and cleaning the
spark plug with solvent and a rag. Also wipe clean the exterior of the spark plug insulator and interior of
the spark plug cap to reduce the possibility of electrical flashover.
•
Use a wire gauge to measure spark plug electrode gap. Where there are any surface irregularities, a wire
gauge will measure more accurately than a flat gauge. Electrode gap specifications are given in the owner's
manuals and shop manuals for each Honda model. All spark plugs, whether new or used, should be accurately gapped before installation. Electrode gap is adjusted by carefully bending the side electrode.
Install spark plugs finger·tight, then use a spark plug wrench for final tightening. The initial placement of
the spark plug is done without using the force of a wrench in order to prevent the possibility of cross·
threading and damaging the cylinder head threads.
Optimum spark plug tightening torque varies with such factors as cylinder head thread material (iron or
aluminuml, the condition of the cylinder head threads, and whether they are clean or dirty, dry or oily.
Spark plug tightening torque specifications may be found in some Honda shop manuals and in some litera·
ture published by spark plug manufacturers, though specifications from different sources will not necessarily coincide. Few people use a torque wrench to install spark plugs anyway.
Spark plugs must be tightened firmly enough to compress the gasket and form a gastight seal, but overtightening may cause cylinder head thread damage. The spark plug gasket can be reused several times, provided it remains with the same spark plug and cylinder with which it was originally used.
44
•
•
•
•
IGNITION SYSTEMS
(
:
:==
Spark Plug Heat Range:
~
'\'~
F
Heat range refers to the spark plug's ability to transfer heat
•
•
from the center electrode's firing tip, through the insu~
lator, through the spark plug shell, to the cylinder head
where heat is dissipated (Fig. 68). The ability of the spark
plug to transfer heat is controlled by the exposed length
of the insulator nose (Fig. 69). When the exposed insu~
lator nose is relatively long, heat from the center elec~
trode's firing tip must travel a relatively long path to reach
the spark plug shell and cylinder head. Conversely, when
the exposed insulator nose is shorter, heat has a shorter
path to follow and is dissipated more easily.
Spark plug manufacturers produce each spark plug size
and model in many heat ranges, using carefully graduated
differences in the length of the exposed insulator nose.
r
The operating temperature of a spark plug varies in re~
lation to exposed insulator nose length and also with all
factors which affect combustion chamber temperature,
such as engine design, engine rpm and load, riding con~
ditions, air~fuel mixture ratios, ignition timing, etc. Foul~
ing is likely to occur when the temperature of the center
electrode's firing tip is less than approximately 450 0 C
(842 0 F). Preignition is likely to occur when the tempera~
ture of the center electrode's firing tip exceeds approx i~
mately 950 0 C (1742 0 F).
I
i
.
Fig. 68 Spark Plug Heat Dissipation
CD
o
o
LONG INSULATOR NOSE EXPOSURE
RAISES OPERATING TEMPERATURE
MEDIUM INSULATOR NOSE EXPOSURE
SHORT INSULATOR NOSE EXPOSURE
LOWERS OPERATING TEMPERATURE
n
Fig. 69 Spark Plug Insulator Nose Length
and Heat Range
The objective of spark plug heat range selection is to equip the engine with spark plugs which will maintain
electrode and insulator tip temperatures hot enough to burn off carbon and chemical deposits that cause
fouling, yet cool enough to prevent preignition .
•
•
Preignition takes place when a hot spot in the combustion chamber (such as a glowing hot spark plug elec~
trode) ignites the air~fuel mixture before the ignition spark occurs. Preignition greatly increases combustion
chamber heat and pressure which may burn or melt the spark plug firing tip. Worse yet, preignition may
cause serious engine damage, such as seized or holed pistons. Therefore, it is safest to select the coldest
spark plug (shortest exposed insulator nose length) that will function without fouling.
Whenever spark plugs are removed from the engine, note the appearance of the insulator tip and electrodes.
An abnormal appearance may indicate the need for engine service or spark plugs of a different heat range.
Most spark plug manufacturers publish literature with full color photographic illustrations of various spark
45
IGNITION SYSTEMS
plug conditions. Obtain a copy of such literature, if available.
Full color photographic illustrations are a far better diagnostic
guide than Fig. 70,71,72 of this manual.
The insulator color of a normal spark plug (Fig. 701 will be
brown, tan, or yellow (shades of gray if unleaded fuel is used).
Electrode wear will be proportionate to the mileage the spark
plug has been used. Normal coloration and wear indicate that
the engine is functioning properly and the spark plug is of suitable heat range.
Fig. 70 Normal Spark Plug Firing
Tip
Fig. 71 Overheated Spark Plug
Firing Tip
Insulator color will become chalk white
to overheat. Ex treme overheating (F ig.
tered insulator appearance with melted
trodes will become abnormally eroded or
as the spark plug starts
71) wi II produce a bl isdeposits, and the eleceven melted.
A spark plug may become overheated from any of the following
conditions:
• Excessively advanced ignition timing.
• Lean air-fuel mixture ratio or intake air leak.
• Detonation (inadequate fuel octane rating or lugging the
engine).
• Preignition (hot spots in the combustion chamber).
• Insufficient engine cooling (no air flow over cooling fins or
loss of liquid coolant).
• Spark plug heat range too high for operating conditions.
•
•
•
•
The insulator nose and electrodes will become black and fouled
(Fig. 721 if spark plug operating temperature is too low to burn
off carbon deposits. or if fuel or oil in the combustion chamber
cause excessive carbon deposits.
Fig. 72 Fouled Spark Plug Firing
Tip
Dry, sooty fouling may be caused by any of the following conditions:
• Excessive use of the choke.
• Prolonged idling or low rpm operation.
• Excessively rich air-fuel mixture ratio.
• Ignition malfunction (insufficient firing voltage).
• Spark plug heat range too low for operating conditions.
Wet, oily black fouling indicates engine wear or damage (worn valve guides, worn piston rings, damaged
pistons), or excessive oil in the fuel-oil mixture of two-stroke engines.
46
•
•
•
-
,
•
•
ELECTRIC STARTER SYSTEM
The electric starting system us~s a direct current motor to transform the battery's electrical energy into the
mechanical energy needed to crank the engine. Amperage requirements are relatively high, so an electro·
magnetic switch and heavy gauge electrical leads are used to make the connection between battery and
starter motor. When the starter motOr is actuated, it drives an overrunning starter clutch that directly or
indirectly (depending on Honda model) engages the engine crankshaft. Reduction gears are used between
the starter motor and starter clutch to multiply the starter motor's tOrque.
D.C. Motor Operating Principle:
When an electric current flows through a wire, magnetic lines of
force encircle the wire (see Fig. 12, page 7). If the current carry·
ing wire is placed between the north and south poles of magnets
(Fig. 73). a reaction occurs between the magnetic field encircling
the wire and the magnetic field between the magnets.
If the directions of the magnetic fields are as indicated in Fig. 73,
then these fields will reinforce each other below the wire where
they run in the same direction, and will cancel each other above
the wire where they run in opposite directions. Consequently, the
wire will be pushed upward (Fig. 741. The current carrying wire is
always pushed away from the side where the resultant magnetic
field is strongest.
t
If the electrical current through the wire were reversed, then the
magnetic field would encircle the wire in the opposite direction
and would react with the field between the two magnetic poles
to push the wire downward.
When a loop of current carrying wire is placed between the north
and south poles of magnets (Fig. 75). the direction of current flow
(and consequently the direction of the magnetic field encircling
the wire) in one side of the loop
is opposite to the direction
of current flow in the other side of the loop
Side
is
forced downward, side
is forced upward, and the loop will
rotate until it stands perpendicular to the lines of magnetic force
between the magnet poles, as indicated in Fig. 75 by the white
loop shown at right angles to the black loop.
®
•
•
®
® .
®
J"-_..... :s
-
Fig, 73 Magnetic Fields Acting on
Current Carrying Wire
Between Magnet Poles
Fig. 74 Resultant Magnetic Field
and Direction of Force on
Wire
TORQUE
DIRECTION
OF CURRENT
~
MAGNETIC
FIELD
---'--
l"'-fp.~
----~
®
Rotation would stop at the point where
is forced downward as far as it can go, and
is forced to its upward limit
(white loop in Fig. 75). but if the direction of current flow is
quickly reversed (before the loop loses its momentum and comes
®
Fig, 75 Motion of Wire Loop
Between Magnet Poles
47
ELECTRIC STARTER SYSTEM
@
@
BATTERY
to a complete stop), the loop will rotate another 180 0 . To achieve
BRUSHES
continuous rotation, it is necessary to provide a means for revers-
COMMUTATOR SEGMENTS
ing current flow whenever the wire loop reaches the position
where it is about to stop.
Reversal of current flow is accomplished by a commutator and
brush arrangement (Fig. 76 - 79). The battery
connected to carbon "brushes"
tator segments
Fig. 76
@
CD
CD
(Fig. 76) is
which slide against commu-
connected to the ends of the wire loop. The
commutator segments rotate with the wire loop, and as they turn,
each brush slides from one commutator segment to the next. The
direction of current flowing through the wire loop is automatically
NO TORQUE
•
•
•
reversed when the brushes contact opposite commutator segments,
and the loop will continue to rotate as long as the battery supplies
current to the brushes.
I n Fig. 76, the wire loop is connected to the battery in the same
A
+'1'1Fig. 77 Elementary D.C. Motor
Position 2
polarity as in Fig. 75 (page 47). Side
®
®
is forced down, side
is forced up, and the wire loop rotates to the position
shown in Fig. 77.
Electrical contact between the wire loop and the battery is broken
•
as the loop coasts through the position shown in Fig. 77. No magnetic force drives the loop until the brushes establish contact with
the opposite commutator segments. Torque increases as the loop
fully enters the field between magnet poles (Fig. 78).
Fig. 78 Elementary D.C. Motor
Position 3
In Fig. 78, sides
®
®
and
is forced down, side
® have rotated 180 Now side
® is forced up, and the wire loop
0.
rotates to the position shown in Fig. 79.
NO TORQUE
The D.C. motor shown in Fig. 76 - 79 has been greatly simplified
to illustrate the basic principles. In an actual D.C. motor, additional loops of wire (armature windings) are used to make the
motor run more smoothly and develop more power. Also, a Honda
starter motor uses four electromagnets (see page 7) rather than the
Fig. 79 Elementary D.C. Motor
Position 4
48
permanent magnets shown here.
•
•
•
-
ELECTRIC STARTER SYSTEM
•
Starter Motor Construction:
A cutaway view of a Honda starter motor is shown in Fig. 80. A diagrammatic view of the same motor is
shown in Fig. 81.
•
•
CD
BRUSH
@
BRUSH SPRING
®
®
®
®
(J)
®
FIELD COIL WINDINGS
FIELD COIL CORE
POSITIVE TERMINAL
COMMUTATOR
ARMATU RE
REDUCTiON GEARS
Fig. 80 Cutaway View of Honda Starter Motor
t
The torque of a motor containing only a single armature winding (Fig. 76 - 79) is neither continuous nor
very effective. A practical starter motor (Fig. 80) contains a large number of wire coils wound around a
laminated iron armature core. At one end of the armature 0) ,there are a number of copper commutator segments
corresponding to the number of armature coils. The commutator segments are insulated from each other by pieces 'of mica. The armature coils are so spaced that, for any position of the
armature, there will be coils near the PRies of the field magnets @ . This makes the torque both continuous and strong. Electromagnets @ ~ are used in the starter motor because they can be made to furnish
a stronger field than the permanent magnets shown in Fig. 76 - 79.
® '
The brushes G) are blocks of graphitic carbon,
which have long service life ~d cause minimum
commutator wear. Springs 0 are used to hold
the brushes firmly against the commutator
®
®
•
•
The brushes G) and commutator
connect the field coil windings @ with the armature 0) windings in series (Fig. 811. Any increase in current therefore strengthens the magnetism of both the field and armature. A series
D.C. motor produces high starting torque, which
is necessary in a starter motor. Relatively thick
wire is used to keep resistance low, enabling the
motor to draw large amperage.
The armature shaft is connected to reduction
gears
which multiply the motor's torque,
enabling it to crank the engine. Reduction gears
may be contained in the engine crankcase or
built into the starter motor housing, depending
on Honda model. Fig. 80 shows a planetary gear
set
within the starter motor housing.
®
®
CD
BRUSH
!J'
FIELD COIL WINDINGS
~
®
®
FIELD COIL CORE
POSITIVE TERMINAL
®
COMMUTATOR
(J)
ARMATURE
5 1~"'?~r7':"\l
;;;;;;:;t~ r--::I-_~!!~::;I:=BATTERY
PLUNGE R
r-"""'STARTER
",BUTTON
SWITCH
Fig,81 Diagrammatic View of Honda Starter Motor
t
49
ElECTRIC STARTER SYSTEM
-'arter Motor Service:
Brushes and commutator segments are the only parts which wear significantly in normal use and are the
only parts which the mechanic can service. Replacement armatures and field coils are not available for
Honda starter motors, so if malfunctions occur in those areas, the entire starter motor must be replaced.
Inspect carbon brushes
CD
BRUSHES
@
@
COMMUTATOR
CD
IFig. 82), and replace if
worn to the limit of their travel within the brush holders,
BRUSH SPRINGS
or refer to the shop manual for service limits in terms of
brush length. Check brush springs
@ , and
replace if
weak or broken. Refer to the shop manual for spring
tension service limits.
Inspect the commutator
@ . The
commutator surface
should be clean and copper segments
insulation
®
•
•
•
8)
smooth. Mica
must be slightly undercut, as shown in
Fig. 83. When copper segments become worn, they will
no longer stand above the mica insulation, and the
Fig. 82 Commutator and Brushes
brushes may not obtain good contact. Mica undercutting
can be performed with a thin saw blade or small file.
@)
®
Rough or irregular surfaces on copper segments can be
COPPER SEGMENT
filed smooth. The use of sandpaper or emery cloth is not
MICA INSULATION
CORRECTION
recommended, as abrasive particles may become imNORMAL
REQUIRED
bedded in the commutator segments. Wipe the commu-
•
tator clean before reassembly.
Continuity tests can be performed to determine whether
a malfunction in the starter motor is due to short circuits
or open circuits in the armature or field coils, and test
procedures are shown in some shop manuals. However,
faulty armatures or field coils in Honda starter motors
can be corrected only by replacing the entire starter
Fig. 83 Commutator Undercutting
motor.
Continuity testing can be done with a YOM, ohmmeter, or a battery powered continuity tester of the same
•
sort used to check static ignition timing (see page 37). Test results, indicating continuity or no continuity,
should correspond logically with the circuit shown in Fig. 81 (page 49). Other results indicate faulty con-
•
nections, or a faulty armature or field coils.
50
•
<
ELECTRIC STARTER SYSTEM
t
•
•
Electromagnetic Starter Switch:
The starter motor draws about 120 amperes of current when cranking the engine. Heavy electrical cable and
a heavy-duty switch are required to properly handle the current. It would not be practical to run heavy
cables up to the handlebar and install a large, heavy-duty switch there. Instead, a small push button switch
on the handlebar activates an electromagnetic starter switch (Fig. 84) that connects the battery to the
starter motor. The electromagnetic starter switch is mounted on the motorcycle frame, near the battery.
When the main switch
CD
and the starter button
(Fig. 84) is turned on,
(2)
®
is depressed, current
flows from
the battery
magnet
within the starter switch. The electro·
0
magnet draws the plunger
the terminals
®
through an electro'
0
into contact with
of the starter switch, completing
a circuit between the battery
®
and starter motor
CD
MAIN SWITCH
11)
PUSH BUTTON STARTER SWITCH
ION HAN OLE BAR)
@
@
ELECTROMAGNET
®
®
o
PLUNGER
STARTER SWITCH TERMINALS
BATTERY
STARTER MOTOR
CD
The electromagnetic starter switch is not ordinarily
repairable and ShOloid be replaced if it malfunctions.
If the starter motor does not actuate when the push
button on the handlebar is depressed, the most fre·
quent cause is simply a discharged battery. If the
battery is somewhat less than completely discharged,
1
the switch will at least produce an audible click as
the plunger moves within the electromagnet.
•
•
Fig. 84 Electromagnetic Starter Switch Circuit
If the battery is well charged, and the starter motor will still not actuate when the push button on the
handlebar is depressed, the electromagnetic switch can be bypassed by short circuiting the switch terminals
with a screwdriver blade or other implement. If bypassing the switch actuates the starter motor, the
problem is in the switch iteself, or in the circuit which leads to the switch's electromagnet. If the starter
motor does not actuate when the switch is bypassed, this indicates that the malfunction may be in the
starter motor.
If the starter motor continues to run after the push button on the handlebar is released, the problem is
usually due to a stuck plunger in the electromagnetic switch. If this malfunction should occur, immediately turn the main switch off, then disconnect the starter motor or battery cable. The starter motor may become seriously damaged, if the engine starts, and the starter motor runs continuously at high rpm.
51
ELECTRIC STARTER SYSTEM
Electromagnetic switch function and continuity can
be checked by connecting it as shown in Fig. 85.
When the electromagnet leads are connected to the
battery, the internal plunger should contact the
switch terminals. creating continuity. Continuity
should cease when the electromagnet leads are disconnected. An ohmmeter is shown in Fig. 85, though
any self-powered continuity tester can be used for
this purpose.
Overrunning Clutch:
Fig. 85 Electromagnetic Starter Switch Testing
CD
®
o
STARTER CHAIN
CLUTCH SPROCKET
SPROCKET HUB
@
CLUTCH HOUSING
®
®
CRANKSHAFT
ROLLER
Reduction gears and sprockets enable the starter
motor to turn at much higher rpm than the engine
in order to develop the necessary cranking force.
When the engine starts to run, however, the starter
motor must be quickly disengaged; otherwise the
starter motor would be driven to excessive rpm by
the engine, and the motor would become seriously
damaged.
•
•
•
The overrunning clutch is a coupling mechanism that
enables the starter motor to engage the engine's
crankshaft or transmission shaft only while the starter
motor is operating under a load (cranking the enginel.
When the engine starts, the engine's increased speed
automatically disengages the starter motor.
Fig. 86 and 87 show cross sectional views of an overrunning c1utch_ The particular type illustrated is installed on the engine crankshaft and is chain driven,
like the starter clutch used in Honda C8-360 and C8SOOT motorcycles.
Fig. 86 Overrunning Clutch (viewed from side
of enginel
The starter motor drives the chain Q) and its
sprocket @ in the direction shown in Fig. 86
(some Honda models use a gear rather than a chain
and sprocketl. The clutch housing @) is attached
to the engine crankshaft
Isome Honda models
mount the clutch housing on a transmission shaft).
Starter engagement is achieved by locking the sprocket to the clutch housing, and disengagement is
achieved by unlocking these parts. Spring loaded
in the clutch housing perform this lockrollers
ino/unlockino function.
•
®
®
CLUTCH SPROCKET
@
CLUTCH HOUSING
®
®
ROLLER
CRANKSHAFT
®
®
The rollers
ride on ramps in the clutch housing
@) . When extended, the rollers wedge the sprocket hub @ tightly against the clutch housing. When
the rollers are retracted, the sprocket hub and clutch
housing are no longer locked together.
Fig. 87 Overrunning Clutch (viewed from front
of enginel
52
When the sprocket drives the clutch housing (i.e.
starter motor cranks enginel, the motion of the
sprocket hub causes the rollers to extend and lock
it to the clutch housing. When the clutch housing rotates at higher rpm than the sprocket li.e. engine
starts and its rpm increases). the relative motion of
these parts retracts the rollers and disengages the
starter motor.
•
•
•
,.
•
•
LIGHTING SYSTEM
Depending on the motorcycle model, lighting may be either A.C. (lighting current supplied by A.C. genera·
tor) or D.C. (lighting current supplied by batteryl. Battery powered D.C. lighting has the advantage of
operating with undiminished intensity when the engine is idling or stopped. When hooking up or trouble·
shooting the lighting circuits, refer to the wiring diagrams shown in the owner's manual or shop manual.
Headlights:
CD
®
RIM
o
PIVOT SCREWS
@
LENS
®
REFLECTOR
®
o
BULB INON·
REPLACEABLE)
FILAMENT
HORIZONTAL
ADJUSTMENT
SCREW
SEALED BEAM
HEADLIGHT
TOP VIEW
~
Fig. 88 Headlight Assembly (CB·550 shown here; this
model is equipped with a sealed beam headlight
for American use)
Headlights may have replaceable bulbs or may be sealed
beam units (Fig. 881. A sealed beam headlight has the lens
@ ,reflector @ ,and lighting filaments
assem·
bled permanently in a sealed unit (Fig. 891. When a fila·
ment in a sealed beam headlight burns out, the entire unit
must be replaced. It is somewhat more expensive to reo
place sealed beam units than bulbs, but the airtight seal
excludes dust and moisture which could otherwise enter
the headlight and tarnish or otherwise reduce the efficien·
cy of the reflector.
®
•
•
There are two types of sealed beam construction. One type
uses a glass reflector which is fused to the lens, forming its
own protective bulb around the filaments. The other type
uses a metal reflector permanently attached to the lens
and sealed, but contalning a conventional looking, non·
removable bulb, as shown in Fig. 89.
SIDE VIEW
Fig. 89 Sealed Beam Unit (metal reflector
type shown here)
53
LIGHTING SYSTEM
The inner surface of a headlight lens is composed of
many light refracting segments. The edges of these seg·
ments are clearly visible from the outside and give the
headlight its characteristic appearance, as though the
lens were ruled off into rectangles (Fig. 90).
The shape of each lens segment is predominantly concave and causes light rays to diverge as they pass
~
,
.1
through the headlight lens (Fig. 91). providing broader
illumination of the road ahead.
Fig. 90 Headlight Beam Reflection and
Refraction
The headlight filaments emit light in all directions, and
•
•
•
a reflector is required to redirect light rays toward the
lens at a suitable angle (Fig. 90).
'{ ~'/t; /
Cm~'mY/:t'~/ LENS
I HORIZONTAL
I ~l
I f a filament is moved off-center between the reflector
SECTION
IIIII
and lens, the light rays it emits will strike the
VERTICAL
LENS SECTION
~
HORiZONTAL
BEAM REFRr,CTION
VERTICAL
*~::.
--...~-
refle~tor
and lens at a different angle. The direction and extent
to which the filament is off'centered can therefore be
used to alter the angle of the headlight beam. This
principle is used to provide "high" and "low" beam
capabilities within a single headlight unit. Dual beam
headlights contain two filaments with just enough dif-
Fig. 91 Headlight Beam Refraction
•
ference in position to provide high and low beam angles.
A handlebar mounted switch enables the rider to light
CD
o
VERTICAL ADJUSTMENT {MOUNTING BOL TS}
either high or low beam filaments.
HORIZONTAL AOJUSTMENT SCREW
Headlight mounting adjustments enable the beam to be
precisely aimed. Vertical adjustment is accomplished by
loosening the headlight mounting bolts
CD
(Fig. 92),
and rotating the headlight assembly up or down. In
some Honda models, such as the one shown in Fig.92,
the headlight mounting bolts are also the directional
signal mounts. Horizontal adjustment is accomplished
by turning an adjustment screw
0
which pivots the
headlight in its rim. Details of the horizontal adjustment
Fig. 92 Headlight Beam Adjustment
•
54
mechanism are shown in Fig. 89.
•
•
•
d
LIGHTING SYSTEM
Taillight and Stoplight:
The taillight on motorcycles intended for street use contains a two-filament bulb
(Fig. 931. One filament
is wired in parallel with the headlight. The other
filament is connected to a switch that completes its circuit when the brakes are applied.
CD
•
•
~
BULB
~
LENS
~
LICENSE PLATE BRACKET
The red taillight lens @ has a clear section on its
lower side to provide license plate illumination. Some
off-road machines le.g. Honda TL-250L which do not
carry license plates may be equipped with a completely
red taillight lens and may use a single filament bulb with
no brake light circuit.
Stoplight Switches:
®
AOJUSTING
NUT
Fig. 93 Taillight and Stoplight Assembly
Fig. 94 Rear Brake Stoplight Switch Adjustment
All Honda motorcycles intended for street use are
equipped with a rear brake stoplight switch of the type
illustrated in Fig. 94 & 95. The rear brake pedal is connected to the operating rod
of the switch. When
the pedal is depressed, this pulls the operating rod
down, and the metal tip of the rod completes a circuit
between the contacts
,lighting the stoplight. When
the brake pedal is released, an internal spring
retracts the operating rod, and its metal tip is withdrawn
from contact, breaking the circuit.
@:'
CONTACT STRIP
@:
OPERATING ROD INSULATOR
([
OPERATING ROD
(J;
@:
AOJUSTING NUT
RETURN SPRING
®
•
•
®
CD
®
An adjusting nut
mounts the switch to the motorcycle frame. The adjusting nut is turned to raise or
lower the switch, controlling the distance the brake
pedal must pull the operating rod before the stoplight
comes on. Switch height shou Id be adjusted so there
is some brake pedal free travel, and the stoplight comes
on just before the brake takes effect.
Fig. 95 Rear Brake Stoplight Switch
55
LIGHTING SYSTEM
"""~))'I
~~.,?
'\0.
Honda street motorcycles of recent manufacture will
also have a front brake stoplight switch. The front brake
switch and rear brake switch are wired in parallel with
each other and in series with the stoplight. so application of either or both brakes will complete the stoplight
circuit. One type of front brake switch uses a plunger
which completes the stoplight circuit when released by
the brake lever (Fig. 961. Some of the Honda models
equipped with hydraulic front brakes use a switch which
is activated by hydraulic pressure in the brake line.
None of the front brake switches on Honda motorcycles
are adjustable.
Fig. 96 Front Brake Stoplight Switch
Turn Signal Lights:
CI'
o
TURN SIGNAL LIGHT
TURN SIGNAL SWITCH
(3)
FLASHER UNIT
@
MAIN SWITCH
®
BATTERY
A simple turn signal circuit is shown in Fig. 97. With
main switch
and turn s;JLnal switch @ on,
current flows from the battery @ . through a flasher
unit @ , to either the left or right turn signal lights
G) ,as determined by the position of the turn signal
switch @ . The flasher unit G) repeatedly opens
and closes the circuit, causing the turn signal lights to
blink.
®
An indicator light, mounted in or near the instruments,
flashes to show the rider that the turn signals are operating. A buzzer is sometimes added to the circuit to
further attract the rider's attention, reminding him to
cancel the signal after completing his turn. If a single
indicator light is installed, it is wired in parallel with the
turn signal switch @ and will operate when either left
or right turn signals are used. If separate left and right
indicator lights are installed, th;x must be wired in para·
Ilel with the turn signal lights UJ
An interior view of the flasher unit used in Honda
motorcycles is shown in Fig. 98. The spring plate
can be likened to an archery bow, held near its center
by the spring plate holder (j) . The contact point
strip
acts like a bowstring, pulling the edges of the
spring plate downward. Current flowing through the
contact point strip heats the strip, causing it to elongate,
releasing tension on the spring plate. The ends of the
spring plate then flip upward against a stop IjJ) ,
raising the contact point strip and separating the contact
points @
•
•
•
•
®
®
Fig. 97 Turn Signal Circuit
After current flow
and contracts, and
ward. This lowers
contact points and
56
ceases, the contact point strip cools
the spring plate again bows down·
the contact point strip, closing the
completing the circuit. The cycle is
•
•
•
s
LIGHTING SYSTEM/HORN
•
repeated, opening and closing the contact points at regular intervals.
®
TERMINAL LUG
(j)
SPRING PLATE HOLDER
Current flowing through the turn signal circuit must
heat the contact point strip sufficiently to operate the
spring plate. If one of the turn signal lights burns out
or becomes disconnected, the remaining light may not
draw enough amperage to develop the necessary heat
and will remain lit, without blinking_
®
CONTACT POINT STRIP
®
@
(j])
@
@
SPRING PLATE
CONTACT POINTS
SPRING PLATE SHOP
COVER
BASE
Horn:
The horn produces sound by vibrating a metal diaphragm. The frequency with which the diaphragm vibrates determines the pitch of the sound, and the extent of diaphragm movement determines the amplitude
(loudness) of the sound.
I n some horns, the sound waves generated by the diaphragm are channeled through a duct of increasing
diameter which amplifies the sound. Other horns are
not fitted with a duct, but have a resonator plate in
front of the diaphragm. Both types are used in Honda
motorcycles.
A cross sectional view of a typical motorcycle horn is
shown in Fig. 99. When the main switch
is closed,
and the horn button @ is depressed, cu rrent flows
from the battery
,through contact points @ &
and through an electromagnet @' . The electromagnet attracts an iron ring
on the diaphragm
shaft @ ,and the diaphragm \j) is pulled inward.
When this occurs, the iron ring strikes an insulator
on the movable contact point
,separating it from
the fixed contact point @ ,and the circuit is broken.
A return spring QJ) then moves the diaphragm shaft
and diaphragm forward. This releases the movable contact point, the contact points close, and the cycle repeats itself as long as the horn button is depressed.
\i
® '
CD
®
®
•
•
7
01JP~6
Fig. 98 Turn Signal Flasher Unit
G)
BATTERY
(j)
@
MAIN SWITCH
®
®
®
@
®
®
FIXED CONTACT
POINT
MOVABLE
CONTACT POINT
CONTACT POINT
INSULATOR
RESONATOR
PLATE
®
The horn is usually equipped with an adjustment screw
@ which controls the height of the contact point
holder @ in relation to the position of the iron ring
on the diaphragm shaft. Adjustment is made by ear, to
produce the best sound..
@
(j])
@
DIAPHRAGM
IRON RING
ELECTROMAGNET
DIAPHRAGM SHAFT
RETURN SPRING
ADJUSTMENT SCREW
@
CONTACT POINT
HOLDER
~
PUSH BUTTON
SWITCH
Fig. 99 Horn
57
FUEL LEVEL AND COOLANT TEMPERATURE GAUGES/COOLING FAN
(j)
o
@
®
®
Fuel Level and Coolant Temperature Gauges:
BATTERY
MAIN SWITCH
VOLTAGE REGULATOR
COOLANT TEMPERATURE METER
COOLANT TEMPE RATU RE SENSOR
®
FUEL LEVEL METER
(j)
FUEL LEVEL SENSOR
®
FLOAT
A diagram of the Honda G L·1 000 fuel level and coolant
temperature gauge circuit is shown in Fig. 100. The
sensors and gauges require a 7 volt power supply. Since
the Honda GL·1000 has a @volt battery, a voltage
regulator
is used to reduce the voltage in this
circuit to 7 volts.
@
The sensors
® (j)
®.
&
are variable resistance devices,
the amount of current flowing through the
meters 4 &
The meter needles are electro·
magnetica Iy controlled and respond by moving across
a calibrated scale in proportion to the current flowing
through their circuits. Lower resistance results in higher
meter readings, and vice versa.
controlli~
is essentiall~ rheostat whose
The fuel level sensor
As fuel level
movable arm is attached to a float
and float height become lower, current must travel
through more of the sensor's resistor to complete its
circuit. When the fuel tank is filled with gasoline, the
float rises, and sensor resistance decreases.
(j)
Fig. 100 Fuel L eve I and Coolant
Temperature Gauge Circuits
CD
o
® .
®
The coolant temperature sensor
responds to heat.
Resistance decreases as temperature rises.
BATTERY
MAIN SWITCH
@
FAN MOTOR
@
THERMOSTATIC SWITCH
•
•
•
Component testing procedures and resistance values are
given in the shop manual.
•
Cooling Fan:
The Honda G L -1000 has an electrically driven fan behind the radiator. Fan operation is required only when
the coolant (a 50-50 mixture of water and ethylene
glycol anti-freeze) temperature exceeds the desired
operating range. The fan motor
(Fig. lOll is therefore connected in series with a thermostatic switch
When coolant temperature reaches a threshold
of 98 0 - 102 0 C (208 0 - 215 0 F l, the thermostatic
switch closes, and the fan will operate until coolant
temperature is lowered enough to open the thermo'
static switch, or until the main switch (]) is turned
off manually.
o.
CD
Fig. 101 Cooling Fan Circuit
58
@
Thermostatic switch operation can be tested by checking electrical continuity while the sensor end of the
switch is immersed in heated liquid. The test procedure
is explained in detail in the shop manual.
•
•
•
GLOSSARY
A.C. generator (alternator)
nating current flow.
lel:
A device for converting mechanical energy into electrical energy of alter-
A.C. generator rotor: A magnet assembly that is rotated to induce electrical current in the stator.
•
•
A.C. generator stator: Nonrotating windings in which the A.C. generator rotor induces electrical current.
alternating current (A.C.): A flow of electricity which continuously reverses direction through repeated
cycles.
ammeter: An instrument for measuring amperage.
ampere (A.): A unit of measurement of the flow rate of electricity. Amperes = volts.;. ohms.
ampere-hour (amp.-hr.): A unit of measurement used mostly to rate the electrical energy a battery can deliver. Ampere·hours = amperes x flow time in hours.
ampere-hour capacity: The amount of electrical energy (expressed in ampere-hours) that a battery can de·
liver for a specified length of time.
armature: The moving component of an electric motor or other electromechanical device.
battery (-01 11-): A D.C. voltage source which converts chemical energy into electrical energy.
chassis ground (
t
,m,): A connection to the motorcycle frame. used to complete an electrical circuit.
capacitor (condenser) (-jt-): A device containing two separated conducting surfaces which temporarily
store electrical energy.
commutator: The part of an electric mC'tor's armature to which the field coils are connected.
detonation: Explosive combustion of the air-fuel mixture in the combustion chamber occurring after the
timed spark.
direct current (D.C.): A flow of electricity continuously in one direction.
dwell angle: The distance (measured in degrees or in percent of one full revolution) which the contact point
cam of an ignition system rotates while the contact points remain closed.
electrolyte: A current carrying substance (e.g. battery acid) in which the conduction of electricity is accompanied by chemical action.
electron: A negatively charged particle orbiting the nucleus of an atom.
energy transfer system: A low tension magneto ignition system in which the contact points are connected
in parallel with the magneto and ignition coil windings.
field coil: A coil of wire wound around an iron core, used in electric motors and in some A.C. generators to
produce a magnetic field.
•
•
fuse (-4'\;»: A protective device, usually a small wire or metal strip, which melts and breaks the circuit if
current exceeds its rated value .
ignition coil
spark.
(]lI[):
An iron core transformer which converts low voltage to high voltage for an ignition
induction: Generation of electrical current in a conductor by variation of a magnetic field affecting the con·
ductor.
magneto: An A.C. generator which serves as the voltage source for ignition.
ohm (
r. ):
A unit of measurement of the resistance to a flow of electricity. Ohms
= volts.;.
amperes.
Ohm's law: The relationship between electromotive force (voltagel, flow rate (amperage), and resistance
(ohms). Volts = amperes x ohms.
59
GLOSSARY
ohmmeter: An instrument for measuring electrical resistance, calibrated in ohms.
parallel circuit: The interconnection of two or more electrical components such that current may flow from
the voltage source directly to each component, without passing through any intervening component to
complete the circuit.
rectifier: A device which converts alternating current into direct current.
resistance: The ability of a conductor to impede the flow of electricity, dissipating electrical energy in the
form of heat. Resistance is measured in terms of ohms.
resistor 1-): A device which can be connected into an electrical circuit for the purpose of impeding the
flow of electricity to a specified degree.
rheostat: A variable resistor having one fixed terminal and one movable contact. A rheostat is adjustable to
produce a range of resistance values.
series circuit: The interconnection of two or more electrical components such that current flowing from the
voltage source must pass through each component in turn to complete the circuit.
•
•
•
series-parallel circuit: The interconnection of electrical components which branches into both series and
parallel current paths.
silicon diode ( ....... ): A two-electrode semiconductor which blocks current flow in only one direction.
spark plug heat range: The ability of a spark plug to transfer heat from its center electrode to its outer shell.
Spark plugs are manufactured with a variety of heat transference rates for different engine temperature
conditions.
spark plug reach: The distance from the shoulder above the spark plug threads to the opposite end of the
threads.
volt (V.): A unit of measurement of the 'electromotive force which causes a flow of electricity. Volts =
amperes x ohms.
voltage regulator: A device which limits its output voltage to a predetermined value or which varies voltage
according to a predetermined plan.
•
voltmeter: An instrument for measuring voltage.
VOM: Volt-ohm-milliameter; a test instrument for measuring voltage, resistance, and amperes, with several
cal ibration ranges.
watt (W.): A unit of measurement of electrical power. Watts = volts x amperes.
zener diode ("*): An electronic device that blocks reverse current flow below a predetermined level and
passes the amount of reverse current which exceeds that level.
60
•
•
•
s
ELECTRICAL SYSTEM TROUBLESHOOTING
PROBLEM
STARTER MOTOR
FAILS TO OPERATE
•
•
POSSIBLE CAUSE
CORRECTION
Discharged
battery.
Determine battery's state of charge. Recharge or replace battery, as necessary.
Faulty starter
motor, electromagnetic switch,
or switch circuit.
With battery well charged, bypass the electromagnetic switch by short circuiting the switch terminals_
If starter motor still does not operate, the problem
is in the starter motor. Check brushes and commutator. Repair or replace starter motor, as necessary .
If starter motor does operate, the problem is in the
switch or switch circu it. Test switch and check circuit continuity.
ENGINE FAILS TO
START (other than
electric starter
problemsl.
Fuel system
problem_
Check to be certain that there is fuel in the fuel tank
and that fuel flows freely to the carburetor. If the
engine has become flooded, clear the combustion
chamber by cranking the engine several times with
the throttle and choke open.
Discharged
battery (battery
ignition systems
only).
Determine battery's state of charge. Recharge or replace battery, as necessary (if battery is not completely discharged, it may be possible to start the
motorcycle using the kickstarter rather than the
electric starter).
Fouled, worn, or
damaged spark
plugs.
Remove and inspect spark plugs. Replace if fouled,
worn, or damaged. Select correct heat range for
your operating conditions_ Check electrode gap.
Ignition system can be tested by cranking the engine
with the spark plug lead connected to the spark
plug, and the spark plug grounded against the
exterior of the engine. The plug should produce a
visible spark, if the ignition system is functioning.
•
•
Faulty ignition
contact points
and/or incorrect
ignition timing.
Inspect ignition contact points, Replace if worn,
burned, or pitted (also replace capacitor if points
appear abnormally burned or pitted!. Adjust gap or
dwell and ignition timing.
Ignition system
has open circuit
or short circuit.
Check electrical continuity of applicable wiring and
switches. Repair or replace, as necessary.
61
ELECTRICAL SYSTEM TROUBLESHOOTING
PROBLEM
ENGINE FAILS TO
START (other than
electric starter
problems).
CORRECTION
POSSI BLE CAUSE I
Faulty magneto
(magneto ign ition
systems only).
Isolate magneto coil from other circuit components,
and check electrical continuity of coil windings. Replace magneto coil if it has an open circuit. Refer to
shop manual for wiring diagram or special instructions.
(continued from
page 61)
Faulty ignition
coil.
Disconnect ignition coil and check electrical continuity of primary and secondary coil windings (refer
to shop manual to determine whether primary and
secondary windings are separated or connected in
your modell. Replace ignition coil if there is an
open circuit.
Test ignition coil performance if test equipment is
available (refer to shop manual) or obtain dealer
assistance.
No cylinder
compression, or
very low
compression.
HARD STARTING,
POOR IDLE
•
Repair engine.
Fouled, worn, or
damaged spark
plugs.
Faulty ignition
contact points
and/or incorrect
ignition timing.
•
•
•
See correction listed under ENGINE FAILS TO
START.
Faulty magneto
(magneto ignition
systems only).
Faulty ignition
coil.
Faulty or misadjusted carbu-
Repair, clean, and adjust. as necessary.
retors.
Low cylinder
compression (may
cause hard starting,
poor idle, and loss
of powerl.
62
Repair engine.
•
•
•
c
ELECTRICAL SYSTEM TROUBLESHOOTING
PROBLEM
Adjust ignition timing.
Incorrect airfuel mixture
ratio.
Adjust carburetors.
SPARK PLUGS SHOW
SIGNS OF OVE RHEATING.
Excessively
advanced
ignition timing.
Adjust ignition timing
ENGINE
OVERHEATS.
Carburetor
mixture too lean.
Adjust, repair, or change jets, as necessary.
PISTON SEIZURE.
Detonation.
Follow fuel octane recommendations
model. Avoid lugging the engine.
Preignition.
Determine and correct cause of hot spots in combustion chamber (e.g. carbon deposits, incorrect
spark plug heat rangel_
Incorrect spark
plug heat range
(plug i~ too
hotl.
Install correct spark plug heat range.
Loss of engine
oil, loss of
coolant (liquid
cooled engines),
restricted air
flow.
Repair as necessary.
Excessive use of
choke.
Open choke as soon as engine warms up.
Excessive idling
and low rpm use.
Avoid excessive idling time. Run at normal rpm in
gear.
Carburetor
mixture too
rich .
Adjust, repair, or change jets, as necessary.
I ncorrect spark
plug heat range
(plug is too
coldl.
Install correct spark plug heat range.
SPARK PLUGS
FOUL.
•
•
CORRECTION
Incorrect
ignition timing.
ENGINE
BACKFI RES.
•
•
POSSIBLE CAUSE
for
your
63
(LECTRICAL SYSTEM TROUBLESHOOTING
I
PROBLEM
POSSI BLE CAUSE
CORRECTION
SPARK PLUGS
FOUL.
Insufficient
firing voltage.
Check ignition system components. Adjust or reo
place, as necessary.
(continued from
page 63).
Excessive oil in
combustion
chamber.
TWO·STROKE ENGINES: Use correct oil·fuel mix·
ture.
FOUR·STROKE ENGINES: Replace worn valve
guides, worn piston rings, or damaged pistons.
BATTERY DOES NOT
BECOME FULLY
CHARGED, OR IS
PE RSISTENTLY
DISCHARGED.
Infrequent
motorcycle use,
low rpm opera·
If motorcycle usage precludes normal charging, the
battery must be periodically removed and connected
to a battery charger.
tion, excessive
use of electric
starter.
Low battery
electrolyte level.
Check electrolyte level, and add water as necessary.
Faulty battery.
Remove battery from motorcycle and connect to a
battery charger. Cher.k battery voltage and specific
gravity after chargillg. Replace battery if it cannot
be fully charged or will not retain a charge.
Open circuit. in
charging system,
poor contact at
battery terminals,
Check circuit continuity. Repair open or short cir·
cuit. Clean battery terminals and cables, and
connect securely.
or short circuits
•
•
•
•
anywhere on the
motorcycle.
BATTERY BECOMES
OVERCHARGED.
EXCESSIVE WATER
LOSS FROM
E LECTROLYTE.
64
Faulty generator,
rectifier, or
voltage regu lator.
Refer to shop manual for wiring diagram, testing
procedure, and specifications.
Faulty voltage
regu lator.
Replace voltage regulator.
•
•
•
'.<-
____________.-1
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