KYMCO MX 125 User manual

PREFACE
This Service Manual describes the
technical features and servicing
procedures for the KYMCO MX’er
125/150.
Section 1 contains the precautions for
all operations stated in this manual.
Read them carefully before starting any
operation.
Section 2 is the removal/installation
procedures for the frame covers which
are subject to higher removal/installation
frequency during maintenance and
servicing operations.
Section 3 describes the inspection/
adjustment procedures, safety rules and
service information for each part,
starting from periodic maintenance.
Sections 4 through 17 give instructions
for disassembly, assembly and
inspection of engine, chassis frame and
electrical equipment.
Most sections start with an assembly or
system illustration and troubleshooting
for the section. The subsequent pages
give detailed procedures for the section.
KWANG YANG MOTOR CO., LTD.
OVERSEAS SALES DEPARTMENT
OVERSEAS SERVICE SECTION
TABLE OF CONTENTS
GENERAL INFORMATION 1
FRAME COVERS/EXHAUST MUFFLER 2
INSPECTION/ADJUSTMENT 3
LUBRICATION SYSTEM 4
FUEL SYSTEM 5
ENGINE REMOVAL/INSTALLATION 6
CYLINDER HEAD/VALVES 7
CYLINDER/PISTON 8
DRIVE AND DRIVEN PULLEYS 9
FINAL REDUCTION/TRANSMISSION
SYSTEM 10
CRANKCASE/CRANKSHAFT/
BALANCE SHAFT 11
FRONT WHEEL/FRONT BRAKE/
FRONT SUSPENSION/STEERING
SYSTEM 12
REAR WHEEL /SWING
ARM/HYDRAULIC BRAKE 13
BATTERY/CHARGING SYSTEM/A.C.
GENERATOR 14
IGNITION SYSTEM 15
STARTING SYSTEM 16
LIGHTS/SWITCHES 17
ONLY ATV ON ROAD AVAILABLE 18
ENGINE CHASSIS
ELECTRICAL
EQUIPMENT
The information and contents included
in this manual may be different from
the motorcycle in case specifications
are changed.

1. GENERAL INFORMATION
1-0
MX’er SYSTEM
1
__________________________________________________________________________________
1
____________________________________________________________________
____________________________________________________________________
____________________________________________________________________
____________________________________________________________________
GENERAL INFORMATION
____________________________________________________________________
SERIAL NUMBER---------------------------------------------------------- 1- 1
SPECIFICATIONS---------------------------------------------------------- 1- 2
SERVICE PRECAUTIONS------------------------------------------------ 1- 4
TORQUE VALUES --------------------------------------------------------- 1-12
SPECIAL TOOLS ----------------------------------------------------------- 1-14
LUBRICATION POINTS -------------------------------------------------- 1-15
CABLE & HARNESS ROUTING ---------------------------------------- 1-18
WIRING DIAGRAM-------------------------------------------------------- 1-22
TROUBLESHOOTING----------------------------------------------------- 1-23

1. GENERAL INFORMATION
1-1
MX’er SYSTEM
SERIAL NUMBER
Location of Frame Serial Numbe
r
Location of Engine Serial Numbe
r

1. GENERAL INFORMATION
1-2
MX’er SYSTEM
SPECIFICATIONS
Name & Model No. LA30AA, AB
Motorcycle Name & Type MX’er
Overall length (mm) 1600
Overall width (mm) 980
Overall height (mm) 990
Wheel base (mm) 1120
Engine type O.H.C.
Displacement (cc) 149.4
Fuel Used 92# nonleaded gasoline
Front wheel 74
Net weight (kg) Rear wheel 78
Total 152
Front wheel 80
Gross weight(kg) Rear wheel 82
Total 162
Front wheel 20*7-8
Rear wheel 22*10-8
Ground clearance (mm) 130
Perform- Breaking distance
(m)(ANSI) 20.6 below
ance Min. turning radius (m) 3
Starting system Starting motor
Type Gasoline, 4-stroke
Cylinder arrangement Single cylinder
Combustion chamber type Semi-sphere
Valve arrangement O.H.C., chain drive
Bore x stroke (mm) 62 x 49.5
Compression ratio 9.7:1
Compression pressure
(kg/cm²) 16.0
Max. output (ps/rpm) 11/7500
Max. torque (kg m/rpm) 1.1/5500
Intake
Open 5.5°BTDC
Port (1mm) Close 27.5°ABDC
timing Exhaust Open 36°BBDC
(1mm)
Close 4°ATDC
Valve clearance Intake 0.06
(cold) (mm) Exhaust 0.06
Idle speed (rpm) 1700rpm
Lubrication type Forced pressure &
wet sump
Oil pump type Inner/outer rotor type
Oil filter type Full-flow filtration
Oil capacity 1.0 liter
Oil exchanging
capacity 0.9 liter
Cooling Type Forced air cooling
Air cleaner type & No Sponge
Fuel capacity 8.1 liters
Type PD
Float lever 14.8mm
Venturi dia.(mm) φ25
Throttle type PISTON
Type CDI
Ignition timing 15°BTDC/1700rpm
Contact breaker Non-contact point type
Spark plug
NGK
CR8E
Spark plug gap 0.60.7mm
Battery Capacity 12V8AH
Clutch Type CVT
Type Helical gear
Operation Automatic centrifugal
type
Type Chain drive
Reduction 1st 2.8-0.95
ratio 2nd 7.226
Counter gear ratio 26.902
Front Caster angle
Axle Trail length
Tire
p
ressure Fron
t
0.2
(kg/cm²) Rear 0.25
Turning Left 44°
angle Right 44°
Brake s
y
ste
m
Rea
r
Disk brake Drum brake
type Front Drum brake
Sus
p
ension Fron
t
Swin
g
type Rear Swing arm
Shock Front Swing
type Rear Swing arm
Frame type SP pipe
Fuel S
y
stem
Carbureto
r
Electrical Equipment
I
g
nition S
y
stem
Tires
Power Drive System
Transmis- sion Gear Reduction
Gear
Moving Device
Engine
Damping Device
Lubrication S
y
stem

1. GENERAL INFORMATION
1-3
MX’er SYSTEM
SPECIFICATIONS
Name & Model No. LA25AB
Motorcycle Name & Type MX’er
Overall length (mm) 1685
Overall width (mm) 980
Overall height (mm) 990
Wheel base (mm) 1120
Engine type OHC
Displacement (cc) 124
Fuel Used 92# nonleaded gasoline
Front wheel 74
Net weight (kg) Rear wheel 78
Total 152
Front wheel 80
Gross weight(kg) Rear wheel 82
Total 162
Front wheel 20*7-8
Rear wheel 22*10-8
Ground clearance (mm) 130
Perform- Breaking distance
(m)(ANSI) 20.6 below
ance Min. turning radius (m) 2.5
Starting system Starting motor
Type Gasoline, 4-stroke
Cylinder arrangement Single cylinder
Combustion chamber type Semi-sphere
Valve arrangement O.H..C., chain drive
Bore x stroke (mm) 56.5 x 49.5
Compression ratio 9.2:1
Compression pressure
(kg/cm²) 14.0
Max. output (ps/rpm) 9.8/7500
Max. torque (kg m/rpm) 0.98/5500
Intake
Open 5.5°BTDC
Port (1mm) Close 27.5°ABDC
Timi
n
g
Exhaust Open 36°BBDC
(1mm)
Close 4°ATDC
Valve clearance Intake 0.06
(cold) (mm) Exhaust 0.06
Idle speed (rpm) 1700rpm
Lubrication type Forced pressure &
wet sump
Oil pump type Inner/outer rotor type
Oil filter type Full-flow filtration
Oil capacity 1.0 liter
Oil exchanging
capacity 0.9 liter
Cooling Type Forced air cooling
Air cleaner type & No Sponge
Fuel capacity 8.1 liters
Type PD
Piston dia. (mm) 14.8mm
Venturi dia.(mm) φ25
Throttle type PISTON
Type CDI
Ignition timing 15°BTDC/1700rpm
Contact breaker Non-contact point type
Spark plug NGK
CR8E
Spark plug gap 0.60.7mm
Battery Capacity 12V8AH
Clutch Type CVT
Type Helical gear
Operation Automatic centrifugal
type
Type Chain drive
Reduction 1st 2.8-0.95
ratio 2nd 7.226 Counter gear ratio 26.902
Front Caster angle
Axle Trail length
Tire
p
ressure Fron
t
0.2
(kg/cm²) Rear 0.25
Turning Left 44°
angle Right 44°
Brake s
y
ste
m
Rea
r
Disk brake Drum brake
type Front Drum brake
Sus
p
ension Fron
t
Swin
g
type Rear Swing arm
Shock Front Swing
type Rear Swing arm
Frame type SP pipe
Fuel S
y
stem
Carbureto
r
I
g
nition S
y
stem
Electrical Equipment
Tires
Power Drive System
Transmis- sion Gear Reduction
Gear
Moving Device
Engine
Damping Device
Lubrication S
y
stem

1. GENERAL INFORMATION
1-4
MX’er SYSTEM
SERVICE PRECAUTIONS
Make sure to install new gaskets, O-rings,
circlips, cotter pins, etc. when
reassembling.
When tightening bolts or nuts, begin with
larger-diameter to smaller ones at several
times, and tighten to the specified torque
diagonally.
Use genuine parts and lubricants.
When servicing the motorcycle, be sure
to use special tools for removal and
installation.
After disassembly, clean removed parts.
Lubricate sliding surfaces with engine oil
before reassembly.

1. GENERAL INFORMATION
1-5
MX’er SYSTEM
Apply or add designated greases and
lubricants to the specified lubrication
points.
After reassembly, check all parts for
proper tightening and operation.
When two persons work together, pay
attention to the mutual working safety.
Disconnect the battery negative (-)
terminal before operation.
When using a spanner or other tools,
make sure not to damage the motorcycle
surface.
After operation, check all connecting
points, fasteners, and lines for proper
connection and installation.
When connecting the battery, the positive
(+) terminal must be connected first.
After connection, apply grease to the
battery terminals.
Terminal caps shall be installed securely.

1. GENERAL INFORMATION
1-6
MX’er SYSTEM
If the fuse is burned out, find the cause
and repair it. Replace it with a new one
according to the specified capacity.
After operation, terminal caps shall be
installed securely.
When taking out the connector, the lock
on the connector shall be released before
operation.
Hold the connector body when
connecting or disconnecting it.
Do not pull the connector wire.
Check if any connector terminal is
bending, protruding or loose.
Confirm
Capacity

1. GENERAL INFORMATION
1-7
MX’er SYSTEM
The connector shall be inserted
completely.
If the double connector has a lock,
lock it at the correct position.
Check if there is any loose wire.
Before connecting a terminal, check
for damaged terminal cover or loose
negative terminal.
Check the double connector cover for
proper coverage and installation.
Insert the terminal completely.
Check the terminal cover for proper
coverage.
Do not make the terminal cover opening
face up.
Secure wire harnesses to the frame with
their respective wire bands at the
designated locations.
Tighten the bands so that only the
insulated surfaces contact the wire
harnesses.
Sna
pp
in
g
!

1. GENERAL INFORMATION
1-8
MX’er SYSTEM
After clamping, check each wire to make
sure it is secure.
Do not squeeze wires against the weld or
its clamp.
After clamping, check each harness to
make sure that it is not interfering with
any moving or sliding parts.
When fixing the wire harnesses, do not
make it contact the parts which will
generate high heat.
Route wire harnesses to avoid sharp
edges or corners. Avoid the projected
ends of bolts and screws.
Route wire harnesses passing through the
side of bolts and screws. Avoid the
projected ends of bolts and screws.
No Contact !

1. GENERAL INFORMATION
1-9
MX’er SYSTEM
Route harnesses so they are neither
pulled tight nor have excessive slack.
Protect wires and harnesses with
electrical tape or tube if they contact a
sharp edge or corner.
When rubber protecting cover is used to
protect the wire harnesses, it shall be
installed securely.
Do not break the sheath of wire.
If a wire or harness is with a broken
sheath, repair by wrapping it with
protective tape or replace it.
When installing other parts, do not press
or squeeze the wires.
Do not pull
too ti
g
ht!
Do not press
or squeeze
the wire.

1. GENERAL INFORMATION
1-10
MX’er SYSTEM
After routing, check that the wire
harnesses are not twisted or kinked.
Wire harnesses routed along with
handlebar should not be pulled tight, have
excessive slack or interfere with adjacent
or surrounding parts in all steering
positions.
When a testing device is used, make sure
to understand the operating methods
thoroughly and operate according to the
operating instructions.
Be careful not to drop any parts.
When rust is found on a terminal, remove
the rust with sand paper or equivalent
before connecting.
Do you understand
the instrument?
Is the instrument set
correctly?
Remove Rust !

1. GENERAL INFORMATION
1-11
MX’er SYSTEM
Symbols:
The following symbols represent the
servicing methods and cautions included
in this service manual.
: Apply engine oil to the
specified points. (Use
designated engine oil for
lubrication.)
: Apply grease for
lubrication.
: Transmission Gear Oil
(90#)
: Use special tool.
: Caution
: Warning
En
g
ine Oil
Grease
Gear Oil
Special

1. GENERAL INFORMATION
1-12
MX’er SYSTEM
TORQUE VALUES
STANDARD TORQUE VALUES
Ite
m
Torque (k
g
f-m) Ite
m
Torque (k
g
f-m)
5mm bolt, nut
6mm bolt, nut
8mm bolt, nut
10mm bolt, nut
12mm bolt, nut
14mm bolt, nut
0.450.6
0.81.2
1.82.5
3.04.0
5.06.0
6.08.0
4mm screw
5mm screw
6mm screw, SH bolt
6mm flange bolt and nut
8mm flange bolt and nut
10mm flange bolt and nut
0.150.4
0.30.5
0.71.1
1.01.4
2.43.0
3.54.5
Torque specifications listed below are for important fasteners.
ENGINE
Item Q‘ty Thread dia.(mm) Torque (kgf-m) Remarks
Stud bolt
Oil filter screen cap
Seat ball stopper bolt
Bearing hold
L cover
Stud bolt
Cam holder
Tappet ADJ nut
Pivot tensioner
Lifter tensioner
Lifter tensioner
MISTON oil drive bolt
Driver face
Clutch outer
Oneway clutch
Balancer shaft
ACG flywheel
Spark plug
Drain bolt mission
Drain plug
Clamper wre harness
Motor srart
Oil pump
Oil pump sprocket
Head CYL bolt
Drive plate nut
Startor
4
1
1
1
8
4
4
2
1
2
1
9
1
1
3
1
1
1
1
1
1
2
2
2
2
1
4
8
30
14
6
6
6
8
6
8
6
6
6
12
12
8
16
14
8
8
12
6
6
6
6
6
22
5
0.71.1
1.02.0
4.55.0
1.01.2
1.01.4
0.71.1
1.82.2
1.41.8
0.81.2
1.01.4
0.350.5
0.81.2
5.56.5
5.06.0
2.43.0
4.05.0
5.06.0
1.12.3
0.81.2
2.03.0
0.81.2
0.81.2
0.81.2
0.81.2
0.81.2
5.06.0
0.81.2

1. GENERAL INFORMATION
1-13
MX’er SYSTEM
Item Q‘ty Thread dia.(mm) Torque (kgf-m) Remarks
R cover
Head cover
Cap R cover
Guide star change handle
Sprocket drive plate
Carburetor
Check bolt oil
9
4
1
3
2
2
1
6
6
6
6
6
6
10
0.81.2
0.81.2
0.81.2
0.81.2
1.01.6
0.81.2
1.01.5
FRAME
Item Q‘ty Thread dia.(mm) Torque (kgf-m) Remarks
Steering stem nut
Swing arm nut
Rear wheel nut
Front wheel nut
Rear shock absorber upper mount bolt
Front shock absorber upper mount bolt
Front shock absorber lower mount bolt
Rear fork axle
Rear hub nut
Rear wheel shaft nut
Rear engine bracket up bolt
Rear engine bracket bolt
Engine hanger bracket bolt
Exhaust muffler lock bolt
1
4
2
2
1
2
2
1
4
2
1
1
1
2
14
10
14
14
10
10
10
14
12
32
10
10
10
8
6.08.0
4.05.0
6.08.0
6.08.0
3.54.5
3.54.5
3.54.5
6.08.0
6.08.0
11.013.0
3.54.5
3.54.5
3.54.5
3.23.8

1. GENERAL INFORMATION
1-14
MX’er SYSTEM
SPECIAL TOOLS
Tool Name Tool No. Remarks Ref. Page
Flywheel puller E003
Lock nut wrench E009
Valve adjuster E012
Valve spring compressor E040
Oil seal and bearing install E014
Universal holder E017
Flywheel holder E021
Clutch spring compressor E027
Bearing puller E008
Bearing puller E018
Bearing puller E020
Bearing puller E031
Nut wrench F010
Float level gauge

1. GENERAL INFORMATION
1-15
MX’er SYSTEM
LUBRICATION POINTS
ENGINE
Lubrication Points Lubricant
Valve guide/valve stem movable part
Cam lobes
Valve rocker arm friction surface
Cam chain
Cylinder lock bolt and nut
Piston surroundings and piston ring grooves
Piston pin surroundings
Cylinder inside wall
Connecting rod/piston pin hole
Connecting rod big end
Crankshaft right side oil seal
Crankshaft one-way clutch movable part
Oil pump drive chain
Balance gear
A.C. generator
Starter one-way clutch
Bearing movable part
O-ring face
Oil seal lip
•Genuine KYMCO Engine Oil (SAE15W-40)
•API SG Engine Oil
Transmission gear and movable parts Gear oil: SAE90#

1. GENERAL INFORMATION
1-16
MX’er SYSTEM
FRAME
The following is the lubrication points for the frame.
Use general purpose grease for parts not listed.
Apply clean engine oil or grease to cables and movable parts not specified. This will avoid
abnormal noise and rise the durability of the motorcycle.
Steering knuckle/Thrust
Cover/Bush/Colla
r
Steering Column Uppe
r
Front Brake
camshaft/Oil
Seal/O-ring
Steering knuckle/Thrust
Cover/Bush/Colla
r
Front Arm Bush
Front Brake
camshaft/Oil
Seal/O-ring
Steering Column Lowe
r
Front Wheel
Oil Seal
Front Arm Bush
Rear Brake Cable
Throttle Cable
Front Brake Cable
Front Wheel
Oil Seal

1. GENERAL INFORMATION
1-17
MX’er SYSTEM
Swing arm Thrust
Cove
r
Rear Brake Cam/
Axle Hub Collar/Oil
Seal/Bearing
Sprocket hub/Rear
Axle Hub Collar/Oil
Seal/Bearing
Driven Sprocket

1. GENERAL INFORMATION
1-18
MX’er SYSTEM
CABLE & HARNESS ROUTING
Rear Brake Cable
Throttle Cable
Front Brake Cable
Handlebar Switch Lea
d
Right Front Brake Cable
Left Front Brake Cable