Accessory for voltmeter with maximum range

Multimeter

 

Fault Diagnosis

Spark plug not sparking

Ignition coil	Symptom	Possible causes (Determine the cause from 1 in sequence)
When the high voltage power is too low.	ўЩ Inner impedance is too small. Use appointed tester to test. ўЪCrankshaft rpm is too low. ўЫTester is disturbed (it is normal when more than one timeЎЇs measured voltage is above the basic). ўЬWiring of ignition system is poorly contacted. ўЭIgnition coil is no good. ўЮCharging coil is bad. (Peak voltage measurement)
Secondary side voltage	While no high-voltage power supply, high voltage power is sporadic.	ўЩTester is wrongly connected. ўЪPoor ignition switch. ўЫConnector of CDI assembly is poorly contacted. ўЬGround wire for CDI assembly is shorted or poorly contacted. ўЭ Poor charging coil (Peak voltage measurement). ўЮ Defective trigger (Peak voltage measurement). ўЯ Connector of high voltage wire is not good. ўа Inferior CDI assembly (after items ўЩ-ўЯ are tested and proved abnormal or spark plug no sparking)
High-voltage power is normal, spark plug no sparking.	ўЩInferior spark plug or secondary leakage of the ignition coil. ўЪ Bad ignition coil.
Charging coil	No high-voltage power supply	ўЩInner impedance is too small. Use appointed tester to test. ўЪCrankshaft rpm is too low. ўЫTester is disturbed (it is normal when more than one timeЎЇs measured voltage is above the basic). ўЬCharging coil is bad. (when items ўЩ-ўЫ are proved normal)
No high-voltage power supply or high voltage power is sporadic.	ўЩDefective ignition coil. ўЪDefective charging coil.
Trigger	When high-voltage power supply is too low.	ўЩInner impedance is too small. Use appointed tester to test. ўЪCrankshaft rpm is too low. ўЫTester is disturbed (it is normal when more than one timeЎЇs measured voltage is above the basic). ўЬTrigger is bad. (when items ўЩ-ўЫ are proved normal)
No high-voltage power supply or high voltage power is sporadic.	ўЩBad ignition coil. ўЪBad trigger.

 

6.3 Ignition System Inspection

* Attention

• When the spark plug is not sparking, check if components of wiring are loosened or badly contacted and make sure if all the voltage values are normal. • There are many brands of multimeters with different interior impedance. The values they measured are not the same.

 

Connect a high-voltage shunt or an ammeter with input impedance higher than 10M¦ё 10CV to the multimeter.

6.3.1 Primary voltage of ignition coil

If an old spark plug is removed and replaced with a good one, ground it with engine.

* Attention

Test when wirings of all the circuits are correct. Normal cylinder compression pressure means to test with spark plug installed on the cylinder head.

 

Disassemble central cover

Connect lead wire of ignition coil; a shunt is connected between the terminal (black/white) of primary coil and the grounding vehicle block.

Press starting motor button or kick starting pedal to measure primary peak voltage of ignition coil.

Min. voltage: over 95V.

 

*Attention

Please do not touch the metal parts of testing probe with your fingers while measuring the voltage, or you will be shocked. Please take care.

 

6.3.2 Charging coil

* Attention

Install spark plug on the head of cylinder. Check in the condition of normal compression pressure

 

Disassemble 4PЎў2P joints of CDI group.
Connect high pressure shunt between 2P (red/white side) and 4P (black side).
Button start motor or step on actuating lever to measure the maximum voltage of charging coil.

Connection method: connect red/white with negative pole and black with black pole

Minimum voltage: more than 95V

*Attention

Fingers can not touch metal part of test stick when measuring voltage. Special attention should be taken when electric shock may happen

 

When the maximum voltage of CDI group terminal is abnormal, disassemble alternator joints.

Connect shunt with charging coil (red/white)

•When voltage is abnormal in CDI group while normal in alternator, joint is in bad contact or wiring is broken.

•That both are abnormal indicates badness of charging coil. Please refer to the check of charging coil meter.

 

6.3.3 Trigger

* Attention

Inspect when spark plug is installed on the cylinder head and compression pressure is normal.

 

Disconnect connector 4P from CDI assembly. A peak-voltage shunt is indirectly connected to the 4P connector (black terminal) and 4P wiring-terminal connector of trigger (blue/white terminal). Press starting motor button or kick pedal level to measure primary peak voltage of trigger.

 

Connecting method: positive (+) to blue/white, negative (-) to black.

Min. voltage: higher than 1.7V.

 

* Attention

Please do not touch the metal parts of testing probe with your fingers while measuring the voltage, or you will be shocked. Please take care.

 

When the peak voltage measured at connector of CDI assembly is abnormal, take down the protecting plate on the right side of vehicle and remove connector of alternator. Trigger (blue/white) is connected with a shunt.

• When the measured voltage at CDI assembly terminal is abnormal, but measured voltage at alternator terminal is normal, it indicates that the connector is of poor contact or wiring is broken.

• When measured results at both sides are abnormal, the trigger is damaged. Please refer to items listed in Diagnosis Table and check.

6.4 CDI Assembly

6.4.1 System Inspection

System inspection

Remove CDI assembly and check components related to the ignition system at wiring terminal.

 

6.4.2 Inspection

Remove CDI assembly and check if connectors are loose or corrosive.

 

Item	Measuring terminal	Standard ValueЈЁ20ЎжЈ©
Main switch	RedЎЄRed/White	On continuity when main switch is Ў°OFFЎ±.
Trigger	Red - Machine short cut	100-200¦ё
Primary coil of ignition coil	Black/WhiteЎЄBlack	0.4¦ё (+/-) 10%
Secondary coil of ignition coil	BlackЎЄspark plug cap (not including spark plug)	4.5-5.5K¦ё (+/-) 10%

 

6.5 Ignition Coil

6.5.1 Removal

Remove vehicle block cover.

Remove spark plug cap.

Remove primary lead wire of ignition coil.

Remove locknut of ignition coil and take out the ignition coil.

Install it in the reverse order of removal.

*Attention

The primary coil is installed with black/white wire connector.

6.5.2 Primary coil inspection

Measure the impedance between terminals of primary coil.

Standard value: 0.4¦ёЎА10% (20Ўж)

Impedance value within the range is good.

Impedance value Ў°ЎЮЎ± indicates broken wire inside the coil. The coil shall be replaced.

 

6.5.3 Secondary coil

Attached with the spark plug, and measure the impedance between lead-wire side of spark plug cap and terminal.

Standard value: 8-11K¦ё (20Ўж)

Impedance value within the range is good.

Impedance value Ў°ЎЮЎ± indicates broken wire inside the coil.

Remove the spark plug cap and measure impedance value between primary side lead-wire of ignition coil cap and negative terminal.

Standard value: 4.5-5.5K¦ёЎА10% (20Ўж)

 

6.6 Trigger

* Attention

Trigger inspection can be performed on the engine.

Inspection

Remove protecting plate of vehicle block.

Remove lead-wire connector of trigger.

Measure the impedance between blue/white terminal of lead wire at engine side and grounding vehicle block.

Standard value: 100-200¦ё (20Ўж)

If measured impedance value is beyond the range, please replace the alternator.

 

 

VII Starting System

Preparatory data-------- 7.1

Fault diagnosis----------7.2

Starting motor-----------7.3

Starting relay------------7.4

Preparatory Data

Precautions on operation

Starting motor removal can be performed on the engine.

Starting clutch removal refers to removal instruction.

 

 

Basic data

Item	Standard	Service Limit
Length of starting carbon brush	12.5mm	8.5mm
Starting idler shaft bushing		8.3mm
Starting idler shaft OD		7.94mm

 

 

Tightening torque

Starting motor clutch cap bolt 12 NЎ¤m

Starting motor clutch locknut 95 NЎ¤m

 

Tools

Locknut wrench

Universal un-adjustable wrench

Fault Diagnosis

Starting motor will not run Starting motor runs weakly Starting motor runs but the engine does not

•Broken Fuse •Low battery •Defective starting clutch

•Low battery •Poor connecting wire contact •Starting motor counter-rotate

•Defective ignition switch •Starting motor gear stuck by •Low battery

•Defective starting clutch foreign substances

•Defective braking switch

•Defective starting relay

•Poor connecting wire contact

•Defective starting motor

7.3 Starting Motor

7.3.1 Removal

* Attention

Before removing starting motor, the ignition switch must be set at Ў°OFFЎ± position. Disconnect battery grounding wire and then turn on the power supply to check if starting motor runs to confirm your operation is safe.

 

First remove the lead-wire clip of starting engine.

Remove starting motor pinch bolt and take down the starting motor.

Roll up the rubber waterproof jacket and remove starting motor connector.

 

7.3.2 Disassembly

Disassemble housing screw, front cover, motor housing and other parts.

 

7.3.3 Inspection

Inspect other component assemblies.

Replace with a new one when there is surface partial friction, injuries or burn.

The commutator shall be cleaned when there is metal particles adhered to its surface.

Inspect for continuity between contact surfaces of other assemblies.

Confirm the discontinuity of armature shaft among surfaces of commutator.

Inspect for continuity of starting motor housing.

Confirm the continuity between conducting terminal and starting motor housing.

Inspect continuity between conducting terminal and brush.

Replace it with a new one if abnormality exits.

Inspect carbon brush holder for continuity. If there is continuity, replace it.

Measure carbon brush length