
17
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IGNITION SYSTEM
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IGNITION SYSTEM LAYOUT --------------------------------------- 17-1
SERVICE INFORMATION -------------------------------------------- 17-2
TROUBLESHOOTING ------------------------------------------------- 17-2
SPARK PLUG ----------------------------------------------------------- 17-3
IGNITION COIL INSPECTION --------------------------------------- 17-3
A.C. GENERATOR INSPECTION ------------------------------------ 17-4
CDI UNIT INSPECTION----------------------------------------------- 17-4

SERVICE INFORMATION
GENERAL INSTRUCTIONS
• Check the ignition system according to the sequence specified in the Troubleshooting. (1-28)
• The ignition system adopts CDI unit and the ignition timing cannot be adjusted.
• If the timing is incorrect, inspect the CDI unit and A.C. generator and replace any faulty parts.
Inspect the CDI unit with a CDI tester
• Loose connector and poor wire connection are the main causes of faulty ignition system. Check
each connector before operation.
• Use of spark plug with improper heat range is the main cause of poor engine performance.
• The inspections in this section are focused on maximum voltage. The inspection of ignition coil
resistance is also described in this section.
• Inspect the ignition switch according to the continuity table specified in page 20-3.
• Inspect the spark plug referring to Section 3.
• Remove the A.C. generator and pulser coil referring to Section 10.
SPECIFICATIONS
Ignition coil resistance
(20℃ )
Pulser coil resistance (20℃ )
Exciter coil resistance (20℃ )
Ignition coil primary side max. voltage
Exciter coil max. voltage
TESTING INSTRUMENT
Electric tester
TROUBLESHOOTING
No spark at plug Engine starts but turns poorly
• Faulty spark plug • Ignition primary circuit
• Poorly connected, broken or shorted wire —Faulty ignition coil
• Faulty ignition switch —Poorly connected wire or connector
• Faulty ignition coil —Poorly contacted ignition switch
• Faulty CDI unit • Ignition secondary circuit
• Faulty A.C. generator —Faulty ignition coil
—Faulty spark plug
—Faulty high-tension wire
—Poorly insulated plug cap
• Improper ignition timing
—Faulty A.C. generator
—Stator not installed properly
—Faulty CDI unit

SPARK PLUG
For spark plug inspection and adjustment,
refer to page (3-5).
IGNITION COIL INSPECTION
Remove the seat and met-in box. (2-3)
Remove the ignition coil
IGNITION COIL PERFORMANCE TEST
Test the ignition coil using a CDI tester.
When there is no spark at the spark plug,
replace the ignition coil with a new one.
IGNITION COIL CONTINUITY TEST
Inspect the continuity of the ignition coil,
primary coil and secondary coil.
Measure the ignition coil resistances at
20℃ .
Secondary coil
without plug cap
Secondary coil with
plug cap
Correctly operate the CDI tester following
the manufacturer‘s instructions.
This is a general test. Accurate ignition
coil test must be performed with a CDI
tester.

A.C. GENERATOR INSPECTION
For A.C. generator removal/installation, refer
to pages 9-3 and 9-5.
Disconnect the pulser coil wire coupler.
Measure the pulser coil resistance between
the blue/yellow wire and ground.
Resistance (20℃ ): 80_ 160Ω
For pulser coil replacement, refer to pages 9-3
and 9-5.
CDI UNIT INSPECTION
Remove the met-in box. (2-3)
Disconnect the CDI coupler and remove the
CDI unit.
Inspect the CDI unit performance using the
CDI tester.
Connect the CDI unit to the CDI tester
special coupler (KB7). Adjust the CDI tester
switch range.
1. OFF
2. P
3. EXT
4. ON1
5. ON2
No spark
↑
↑
Good spark
Good spark
Good spark
No spark
No spark
CDI Tester Special Coupler
Correctly operate the CDI tester following
the manufacturer‘s instructions.
Measure the resistance in the XΩ range.

RESISTANCE INSPECTION
Measure the resistance between the terminals.
Replace the CDI unit if the readings are not
within the specifications in the table below.
Use the x KΩ range for the Sanwa Tester.
Use the x 100Ω range for the Kowa Tester.
Unit: KΩ
• Due to the semiconductor in circuit, it
is necessary to use a specified tester
for accurate testing. Use of an
improper tester in an improper range
may give false readings.
• Use a Sanwa Electric Tester (07308-
0020000) or Kowa Electric Tester
(TH-5H).
• In this table, “Needle swings then
returns” indicates that there is a
charging current applied to a condenser.
The needle will then remain at “∞ ”
unless the condenser is discharged.