KS Motorcycles K-LIGHT125 User manual
Maintenance Manual of
Two-wheeled Motorcycle
(K-LIGHT125)
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Contents
Contents.................................................................................................................................................................- 1 -
Preface...................................................................................................................................................................- 4 -
Preparatory information.........................................................................................................................................- 5 -
General safety................................................................................................................................................- 5 -
Maintenance rules..........................................................................................................................................- 6 -
Motorcycle identification.............................................................................................................................- 10 -
Important notes............................................................................................................................................- 11 -
Special tools.................................................................................................................................................- 11 -
Specification table ........................................................................................................................................- 18 -
Fault diagnosis.............................................................................................................................................- 20 -
Inspection / adjustment................................................................................................................................- 47 -
Inspection and Maintenance of Electrical System...............................................................................................- 72 -
I. Battery/Charging System..................................................................................................................................- 74 -
1.1 Preparatory Information.........................................................................................................................- 74 -
1.2 Fault Diagnosis......................................................................................................................................- 75 -
1.3 Battery ...................................................................................................................................................- 76 -
1.4 Charging System....................................................................................................................................- 77 -
1.5 Disassembly of Voltage and Current Regulator.....................................................................................- 78 -
1.6 Alternator Charging Coil .......................................................................................................................- 79 -
1.7 Disassembly of Alternator .....................................................................................................................- 79 -
II. Ignition System...............................................................................................................................................- 83 -
2.1 Preparatory Information.........................................................................................................................- 83 -
2.2 Fault Diagnosis......................................................................................................................................- 85 -
2.3 Trigger ...................................................................................................................................................- 86 -
2.4 Ignition Coil...........................................................................................................................................- 86 -
2.5 Spark Plug..............................................................................................................................................- 88 -
2.6 ECU.......................................................................................................................................................- 88 -
III. Starter System................................................................................................................................................- 90 -
3.1 Preparatory Information.........................................................................................................................- 90 -
3.2 Fault Diagnosis......................................................................................................................................- 91 -
3.3 Starter Motor..........................................................................................................................................- 91 -
3.4 Starter Relay ..........................................................................................................................................- 92 -
IV. Bulbs /Switches/Meters .................................................................................................................................- 95 -
4.1 Preparatory Information.........................................................................................................................- 95 -
4.2 Fault Diagnosis......................................................................................................................................- 96 -
4.3 Replacement of Headlight Bulb.............................................................................................................- 97 -
4.4 Replacement of Front Turn Signal Light Bulb ......................................................................................- 98 -
4.5 Replacement of Taillight Bulb...............................................................................................................- 98 -
4.6 Replacement of License Light Bulb ......................................................................................................- 99 -
4.7 Meters....................................................................................................................................................- 99 -
4.8 Ignition Switch.....................................................................................................................................- 100 -
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4.9 Electric horn ........................................................................................................................................- 102 -
4.10 Handlebar Switch...............................................................................................................................- 104 -
Inspection and Maintenance of Chassis.............................................................................................................- 105 -
V. Brake.............................................................................................................................................................- 108 -
5.1 Preparatory Information.......................................................................................................................- 108 -
5.2 Fault Diagnosis....................................................................................................................................- 109 -
5.3 Front Brake Disc..................................................................................................................................- 109 -
5.4 Rear Brake Disc...................................................................................................................................- 111 -
5.5 CBS......................................................................................................................................................- 113 -
VII. Front Wheel/Front Suspension...................................................................................................................- 134 -
7.1 Preparatory Information.......................................................................................................................- 134 -
7.2 Fault Diagnosis....................................................................................................................................- 135 -
7.3 Front Wheel.........................................................................................................................................- 135 -
7.4 Handlebar.............................................................................................................................................- 140 -
7.5 Front Fork............................................................................................................................................- 145 -
7.6 Front Shock Absorber..........................................................................................................................- 151 -
VIII. Rear wheel/rear suspension ......................................................................................................................- 160 -
8.1 Preparation of Information-.................................................................................................................- 160 -
8.2 Fault Diagnosis....................................................................................................................................- 160 -
8.3 Rear wheel...........................................................................................................................................- 161 -
8.4 Rear shock absorber.............................................................................................................................- 166 -
8.5 Rear RockerArm.................................................................................................................................- 168 -
8.6 Chain drive ..........................................................................................................................................- 171 -
IX. Fuel Tank/Seat.............................................................................................................................................- 180 -
9.1 Preparatory information.......................................................................................................................- 180 -
9.2 Fault Diagnosis....................................................................................................................................- 180 -
9.3 Seat......................................................................................................................................................- 181 -
9.4 Fuel Tank .............................................................................................................................................- 182 -
X. Disassembly/Installation of Engine..............................................................................................................- 190 -
10.1 Preparatory information.....................................................................................................................- 190 -
10.2 Fault Diagnosis..................................................................................................................................- 190 -
10.3 Disassembly of Engine ......................................................................................................................- 191 -
10.4 Installation of Engine.........................................................................................................................- 191 -
Inspection and maintenance of engine...............................................................................................................- 193 -
XI. Lubrication System......................................................................................................................................- 195 -
11.1 Preparatory Information.....................................................................................................................- 195 -
11.2 Fault Diagnosis..................................................................................................................................- 195 -
11.3 Fuel Pump..........................................................................................................................................- 196 -
XII. Cylinder head / valve .................................................................................................................................- 201 -
12.1 Preparatory information.....................................................................................................................- 201 -
12.2 Fault Diagnosis..................................................................................................................................- 202 -
12.3 Cylinder Head....................................................................................................................................- 202 -
12.4 Valve inspection.................................................................................................................................- 206 -
12.5 Replacement of Valve Guide .............................................................................................................- 207 -
12.6 Finishing Valve Seat Ring..................................................................................................................- 208 -
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12.7 Installation of Cylinder Head.............................................................................................................- 209 -
XIII. Cylinder Block and Piston........................................................................................................................- 211 -
13.1 Preparatory Information.....................................................................................................................- 211 -
13.2 Fault Diagnosis...............................................................................................................................- 212 -
3.3 Cylinder Block.....................................................................................................................................- 213 -
13.4 Piston.................................................................................................................................................- 214 -
13.5 Installation of Cylinder Block............................................................................................................- 218 -
XIV. Clutch / kickstarter mechanism..............................................................................................................- 221 -
14.1 Preparatory Information.....................................................................................................................- 221 -
14.2 Fault Diagnosis..................................................................................................................................- 221 -
14.3 Clutch.................................................................................................................................................- 222 -
14.4 Kickstarter Mechanism......................................................................................................................- 224 -
14.5 Disassembly of primary and auxiliary shafts.....................................................................................- 225 -
XV. Variable speed gear.....................................................................................................................................- 229 -
15.1 Preparatory Information.....................................................................................................................- 229 -
15.2 Fault Diagnosis..................................................................................................................................- 229 -
15.3 Shift mechanism................................................................................................................................- 230 -
15.4 Installation.........................................................................................................................................- 233 -
XVI. Crankcase .................................................................................................................................................- 235 -
16.1 Preparatory Information.....................................................................................................................- 235 -
16.2 Fault Diagnosis..................................................................................................................................- 235 -
16.3 Crankcase...........................................................................................................................................- 236 -
16.4 Crankshaft combination.....................................................................................................................- 239 -
XVII. Exhaust Emission Control System..........................................................................................................- 246 -
17.1 Guarantee of Exhaust Emission Control System...............................................................................- 246 -
17.2 Regular Maintenance Notice .............................................................................................................- 246 -
17.3 Mechanical Function of Exhaust Control System .............................................................................- 247 -
17.4 Catalyst Conversion System..............................................................................................................- 247 -
XVIII. Electronic Injection System...................................................................................................................- 251 -
18.1 Introduction of Electronic Injection System......................................................................................- 251 -
18.2 EFI Parts............................................................................................................................................- 252 -
18.3 Fault Maintenance and Diagnosis Method ........................................................................................- 268 -
18.4 Common Troubleshooting Methods ..................................................................................................- 271 -
Circuit Diagram................................................................................................................................................ 277
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Preface
This Maintenance Manual is the explanation for the maintenance essentials of
dealers.
Preparatory information includes all matters needing attention for operation in
the Maintenance Manual. Please read this Manual carefully before operation.
Inspection and adjustment is the explanation for the essentials of inspection and
adjustment, as well as the safety of motorcycles and performance maintenance
methods of parts, which should be implemented from the time of regular inspection.
Chapter II and subsequent chapters are the explanations for the decomposition,
combination and inspection of the others of electrical equipment, motorcycle and
engine.
Exploded diagrams and system diagrams, maintenance fault diagnosis and
instructions are provided above all chapters.
Note:
The style or structure of the motorcycle and the photographs, pictures or
instructions on the Manual are subject to change without further notice.
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Preparatory information
General safety
Special tools
Maintenance rules
Specification table
Motorcycle identification
Fault diagnosis
Important notes
General safety
Carbon monoxide
If the engine must be started, ensure that the workplace is well-ventilated and do not operate the engine in a closed
place.
Notes
Exhaust gas contains
carbon monoxide, a kind of toxic gas, which may cause people to lose consciousness and
possibly lead to death.
It is necessary to operate the engine in an open place, and exhaust cleaning system should be used when the
engine is operated in a closed place.
Gasoline
Workers should operate in a well-ventilated workplace. Smoke and fire are strictly prohibited in the workplace or
the place where gasoline is stored.
Battery
Battery may emit explosive gas. Keep it away from spark, open flames and smoking area. Keep it well ventilated
when it is being charged.
Battery contains sulfuric acid (electrolyte). Burns may be caused when it contacts with skin or eyes. Therefore,
workers should wear protective clothing and mask.
——If electrolyte splashes on the skin, rinse it immediately with fresh water.
——If electrolyte splashes in the eyes, rinse them with fresh water immediately for more than 15 minutes
and consult a doctor.
The electrolyte is toxic. If you accidentally drink electrolyte, you should immediately drink plenty of water, milk
and magnesium oxide milk (a laxative antacid) or vegetable oil, and consult a doctor. Keep it out of the reach of
children.
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Maintenance rules
During the maintenance of the motorcycle, use metric
tools as much as possible. The motor
cycle may be
damaged due to the use of incorrect tools.
Before removing or opening the fender for
maintenance, clean the dirt from the outside of part or
assembly, to prevent the dirt from falling into the
engine, chassis or brake system.
After disassembling and before measuring the wear
value, clean the parts and blow them with a compressed
air machine.
The rubber parts may deteriorate due to aging and are
easily damaged by solvents or oils. They should be
inspected before reassembly and replaced if necessary.
Set
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Loosen parts with multiple assemblies from outside to
inside. First loosen small assemblies.
Complex assemblies such as gearboxes should be
stored in the proper assembly order for future assembly.
Complex assemblies such as gearboxes should be
stored in the proper assembly order for future assembly.
The parts that will no longer be used should be replaced
promptly before dismantling.
The lengths of bolts or screws are different for
assembly and fender, and they must be installed in the
proper positions. If they are mixed, put the bolt in the
hole and check whether it is proper.
Installation of oil seal: the oil seal groove should be
filled with lubricating grease, check whether the oil seal
is smooth and may be damaged.
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Installation of rubber hose (fuel, vacuum, or coolant):
its end should be plugged into the bottom of connector,
so that there is enough place at the hose to clamp the
connector. Rubber or plastic dirt-proof boots should be
fitted at the original design position.
Disassembly of ball bearing: use tools to support one or
two (inner and outer) bearing rolling rings. If the
force is applied to only one rolling ring (either inside or
outside), the bearings may be damaged when being
disassembled and they must be replaced.
Groove
Clamp
Connector
Bearing may be damaged in the two examples
above.
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Loose cable is a potential safety hazard of electrical
safety. Check the next cable after clamping the cable, to
ensure electrical safety;
Wire clamps are not allowed to bend in the direction of
the solder joint;
Bundle the cable at the designated location;
Cables are not allowed to be placed at the end of frame
or at the corners;
Cables are not allowed to be placed at the ends of bolts
or screws;
Keep cables away from heat source or the position
where the cable may be caught during movement;
Cables should not be kept too tight or loose when being
placed along the faucet handle, and must not interfere
with adjacent parts in any steering position;
Cables should be smoothly placed and must not be
twisted or knotted;
Before con
nectors are mated, check whether the
connector sheath is damaged and the connector is
opened excessively;
If the cable is at a sharp or corner, please protect it with
tape or a hose;
After the cable is repaired, please bind it up reliably
with tape;
The control wire must not bend or twist. If the control
line is damaged, inflexible operation may be caused;
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Motorcycle identification
1
．
The frame serial number
①
is:
*LBBU3400?????????*, as shown in the figure. The
10th digit of vehicle identification code is the year, the
11th digit is the production factory code, and a “*”
mark is added at the beginning and the end of the frame
number.
2. Frame nameplate riveting position, as shown in the
figure.
Frame nameplate, as shown in the figure.
3. Serial number of engine
①
is marked at the housing
of crankcase, as shown in the figure.
Engine number: QJ157FMI-A*□□□□□□□*
白
/
绿
蓝
/
白
触发头
ECU
黑/红1
黑/白1
点火电源
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Important notes
1. Please use the parts from dealers. Damage may be caused to the engine when the parts that do not meet the design
specifications of dealers used.
2. Only metric tools can be used for maintenance work. Metric bolts, nuts and screws are not interchangeable with
imperial fasteners.
3. During reassembly work, use new washers, O-rings, split pins and locking plates.
4. When tightening bolts or nuts, first tighten the bolts with large diameter or leaning to the inner side, and then
gradually tighten them to the specified torque in the diagonal order, unless otherwise specified.
5. Wash the removed parts with a cleaning solution. Lubricate all sliding surfaces before assembly.
6. After assembly, check whether all parts have been correctly installed and operated.
7. Degrease and remove oil before measurement. Add recommended lubricant to the lubrication location during
assembly.
8. When the engine and drive system need to be stored for a long time after being disassembled, please apply
lubricant to the surface of the parts to prevent rust and dust.
Special tools
Special tool refers to a tool specially designed for assembling or disassembling some parts of motorcycle and
using it on a specific location. Appropriate special tools are indispensable for complete and accurate adjustment
and assembly operations. Parts should be disassembled and assembled safely, reliably and quickly using special
tools, so as to improve work efficiency and save labor.
1. Tools for maintenance of engine
When disassembling the engine, certain parts can be smoothly assembled and disassembled only using
specially designed tools.
The list and pictures of special tools for the disassembly and assembly of engine parts are shown in Tables
1-1 and 1-2.
Table 1-1
Name
Remarks
Special socket wrench
Clutch holder
Flywheel puller
Feeler gauge
Bearing removal tool
Bearing installation tool
Oil seal replacer
Disassembly tool handle
Piston pin pull-out device
Piston ring opening clamp
Spark plug socket wrench
Measuring clutch thickness
Cylinder diameter tester
Dial gauge
Used to remove the flywheel bolts, Fig. 1-3
Fig. 1-4
Fig. 1-5
Fig. 1-6
Fig. 1-7
Fig. 1-8
Fig. 1-9
Fig. 1-10
Fig. 1-11
Fig. 1-12
Fig. 1-13
Fig. 1-14
Fig. 1-15
Measure inner diameter of piston pin, Fig. 1-16
Table 1-2
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Fig. 1-3
Fig. 1-4
Fig. 1-5
Fig. 1-6
Fig. 1-7
Fig. 1-8
Feeler gauge
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Fig. 1-9
Fig. 1-10
①Handle
Fig. 1-11
Fig. 1-12
①Opening clamp ②Piston
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Fig. 1-13
Fig. 1-14
Fig. 1-15
Fig. 1-16
2. Tools for chassis maintenance
The list and pictures of common and special tools for the disassembly and assembly of chassis parts are shown in Tables 1-17
and 1-18.
Table 1-17
Name Remarks
Torque wrench
Allen wrench
Socket wrench
Micrometer
Magnetic frame, V-shaped block
Dial gauge
Vernier caliper
Spring snap ring pliers
Knock-on screwdriver
Front fork oil seal installation tool
Front fork seal driving tool
Steering nut wrench
Fig. 1-19
Fig. 1-20
Fig. 1-21
Fig. 1-22
Fig. 1-23
Fig. 1-24
Fig. 1-25
Fig. 1-26
Fig. 1-27
Fig. 1-28
Fig. 1-29
Fig. 1-30
(1) Common tools for chassis maintenance
Table 1-18 (continued)
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Fig. 1-19
Fig. 1-20
Fig. 1-21
Fig. 1-22
Fig. 1-23
Fig. 1-24
1. Socket head 2. Jiggle bar 3. Ratchet wrench 4. Connecting rod
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Fig. 1-25
Fig. 1-26
Fig. 1-27
Fig. 1-28
(2) Special tools for maintenance of chassis: Front fork seal driving tool.
Fig. 1-29
(3) Steering nut wrench.
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Fig. 1-30
3. Tools for electrical parts
The list and pictures of special tools for the testing of electrical parts are shown in Table 1-31 and 1-32.
Table 1-31
Name
Remarks
Multimeter
Ignition tester
Fig. 1-33
Fig. 1-34
Table 1-32 (continued)
Fig. 1-33
Fig. 1-34
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Specification table
Model K-LIGHT125 Engine type QJ157FMI
L (mm) 2140 Fuel type Unleaded gasoline
W (mm) 800
Number of
cylinders
1
H (mm) 1050
Inner diameter *
stroke
φ56.5×49.5
Wheelbase mm 1440 Total displacement 124cm³
Weight (kg)
(Curb weight)
Front
axle
69 Starting mode Electric / kickstarter
Rear
axle
76 Cooling mode Air-cooled
Total 145 Lubrication mode Pressure and splash
lubrication
Tire
Specifications
Front tire 90/90-17
Engine
Air filter 3XG/sponge
Rear tire 130/90-15
Transmission gear
Clutch type Wet multi-plate
friction type Tank capacity 11.8L±0.5L
Speed-varying
mode Five-speed
transmission
Performance
Throttle valve: 30C-21
Drive mode Chain drive Idle speed 1500±100rev/min
Electric equipment
Battery
capacity/type 12V6Ah
（YTX7A-BS) Maximum torque 8.9Nm/7500rev/min
Maximum
horsepower 7.8kw/9000rev/min
Alternator
capacity 100W/5000rpm
Compression ratio 9：1
Spark plug D7RTC
Maximum speed 90km/h five-speed
Spark plug gap 0.7±0.1mm
Brake
Diameter of front
brake disc φ280mm
Ignition mode ECU Diameter of rear brake
disc φ240mm
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Table of contents
