KYMCO K-XCT 125i User manual

K-XCT 125i
By KWANG YANG Motor Co., Ltd.
1st Edition, Aug. 2012
All rights reserved. Any reproduction or
unauthorized use without the written
permission of KWANG YANG Motor Co., Ltd.
is expressly prohibited.
T100-LKG5-A1

K-XCT 125i
PREFACE
This Service Manual describes the
technical features and servicing
procedures for the KYMCO
K-XCT 125i.
Section 1 contains the precautions for
all operations stated in this manual.
Read them carefully before any
operation is started.
Section 2 is the removal/installation
procedures for the frame covers
which are subject to
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 5 to 11 give instructions for
disassembly, assembly and
adjustment of engine parts. Section
13-14 is the AFI system. Section 15 to
16 is the removal/ installation of
chassis. Section 17 to 20 states the
testing and measuring methods of
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.
QUALITY TECHNOLOGY DEPT.
EDUCATION SECTION
TABLE OF CONTENTS
GENERAL INFORMATION 1
EXHAUST MUFFLER/FRAME
COVERS 2
INSPECTION/ADJUSTMENT 3
LUBRICATION SYSTEM 4
ENGINE REMOVAL/INSTALLATION 5
CYLINDER HEAD/VALVES 6
CYLINDER/PISTON 7
DRIVE AND DRIVEN PULLEYS 8
FINAL REDUCTION 9
A.C. GENERATOR/STARTER
CLUTCH 10
CRANKCASE/CRANKSHAFT 11
COOLING SYSTEM 12
Fi DIAGNOSTIC TOOL OPERATION 13
FUEL INJECTION SYSTEM 14
HANDLEBAR/FRONT
WHEEL/FRONT BRAKE/FRONT
SHOCK ABSORBER/STEERING
STEM
15
REAR BRAKE/REAR FORK/REAR
WHEEL/REAR SHOCK ABSORBER` 16
BATTERY/CHARGING SYSTEM 17
IGNITION SYSTEM 18
STARTING SYSTEM 19
LIGHTS/METERS/SWITCHES 20
The information and contents
included in this manual may be
different from the motorcycle in case
specifications are changed.
CHASSIS ELE
C
TRI
C
AL
EQUIPMENT
ENGINE

1. GENERAL INFORMATION
1-0
K-XCT 125i
1
________________________________________________________________________________
________________________________________________________________________________
________________________________________________________________________________
________________________________________________________________________________
________________________________________________________________________________
GENERAL INFORMATION
________________________________________________________________________________
SERIAL NUMBER------------------------------------------------------------------------------------1-1
SPECIFICATION -------------------------------------------------------------------------------------1-2
SERVICE PRECAUTIONS-------------------------------------------------------------------------1-3
TORQUE VALUES-----------------------------------------------------------------------------------1-8
SPECIAL TOOLS----------------------------------------------------------------------------------- 1-10
LUBRICATION POINTS -------------------------------------------------------------------------- 1-12
TROUBLESHOOTING ---------------------------------------------------------------------------- 1-14
1

1. GENERAL INFORMATION
1-1
K-XCT 125i
Identification Numbers Record

1. GENERAL INFORMATION
1-2
K-XCT 125i
SPECIFICATIONS
Name K-XCT 125i
Model No. SK25BA
Overall length 2120 mm
Overall width 785 mm
Overall height 1280 mm
Wheel base 1450 mm
Engine type 4strokeO.H.C.
Displacement 124.8 cc
Fuel Used 92# nonleaded
gasoline above
Curb weight
(kg)
Front wheel -
Rear wheel -
Total 157
Max. weight
capacity (kg)
Front wheel -
Rear wheel -
Total 247
Ground clearance (mm) 140
Braking distance (m) 7.9m / 40 km/hr
Min. turning radius (mm) 2450
Engine part
Starting system Starting motor
Type Gasoline 4-cycle
C
y
linder arran
g
ement Sin
g
le c
y
linde
r
Combustion chamber t
y
p
e
Semi-sphere
Valve arran
g
ement O.H.C.4V
Bore x stroke (mm) φ54 * 54.5
Compression ratio 11.2:1
Compression pressure
(
k
g
/c
m
²
)
15
Max. output (ps/rpm) 10.6
/
9000
Max. torque (k
g
-m/rpm) 12.0 / 7000
Intake Timing Open 8° BTDC
Close 31° BTDC
Exhaust
Timing Open 6° BTDC
Close 32° BTDC
Valve
clearance Intake 0.10
Exhaust 0.10
Idle speed (rpm) 1800±100 rp
m
Cooling Type Liquid coolin
g
Lubrication type Forced pressure &
wet sum
p
Oil pump t
y
pe Inner/outer roto
r
Oil filter t
y
pe Full-flow filtration
Oil capacit
y
1.2 lite
r
Exchan
g
in
g
capacit
y
1.0 lite
r
Fi in
j
ection s
y
stem
Air cleaner type & No Paper element, wet
Fuel capacity 10 liters
Brand Synerject
Throttle Body Butterfly type
Venturi diameter (mm) 27
Fuel pump pressure 3 bar
Electrical system
Ignition type ECU
Ignition timing 4°～32°
Spark plu
g
CR7E
Spark plu
g
g
ap 0.7m
m
Batter
y
Capacit
y
12V10AH
Transmission s
y
stem
Clutch t
y
pe Dry multi-disc
Transmission type CVT
Operation type Auto centrifugal
Reduction
g
ear t
y
pe Two-stage reduction
Reduction ratio 1st 0.83 ~ 2.2
2nd 10.41
Movin
g
device
Tire type Tubeless
Tire spec. Front wheel 120/70-14
Rear wheel 150/70-13
Tire pressure
(
k
g
/c
m
²
)
Front wheel 2.0
Rear wheel 2.25
Wheel material Aluminiu
m
Turning angle Left 40
Right 40
Brake type Front Disk brake
Rear Disk brake
Damping Device
Suspension
type
Front Telescope
Rear Swing arm
Shock absorber
stroke
Front 110 mm
Rear 93 mm

1. GENERAL INFORMATION
1-3
K-XCT 125i
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.
Apply or add designated greases and
lubricants to the specified lubrication
points.
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.
If the fuse is burned out, find the cause
and repair it. Replace it with a new one
according to the specified capacity.

1. GENERAL INFORMATION
1-4
K-XCT 125i
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.
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.
After clamping, check each wire to make
sure it is secure.
Confirm
Capacity

1. GENERAL INFORMATION
1-5
K-XCT 125i
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 that 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.
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 protector 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.
After routing, check that the wire
harnesses are not twisted or kinked.
Do not pull
too tight！
No Contact
Do not press or
squeeze the wire

1. GENERAL INFORMATION
1-6
K-XCT 125i
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？
Remove Rust！

1. GENERAL INFORMATION
1-7
K-XCT 125i
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
Special
Engine Oil
Grease
Gear Oil
＊

1. GENERAL INFORMATION
1-8
K-XCT 125i
Item Qty Thread dia.(mm) Torque (kgf-m) Remarks
Cylinder head boltA
Cylinder head bolt B
Oil filter screen cap
O2 sensor
Cylinder head cover
Tappet adjusting hole cap
Cam chain set plate
Engine oil drain bolt
Clutch outer nut
Clutch drive plate nut
Starter motor mounting bolt
Oil pump bolt
Drive face nut
Spark plug
A.C. Generator flywheel
Cam chain tensioner pivot
6
6
30
12
6
30
6
12
12
28
6
6
12
10
12
6
0.7~1.1
0.7~1.1
2.0~3.0
0.7~1.1
0.8~0.9
1.0~2.0
1.0~1.4
2.0~3.0
5.0~6.0
5.0~6.0
0.8~1.2
0.7~1.1
5.5~6.5
1.0~1.4
5.0~6.0
0.8~1.2
TORQUE VALUES

1. GENERAL INFORMATION
1-9
K-XCT 125i
TORQUE VALUES
FRAME

1. GENERAL INFORMATION
1-10
K-XCT 125i
SPECIAL TOOLS

1. GENERAL INFORMATION
1-11
K-XCT 125i

1. GENERAL INFORMATION
1-12
K-XCT 125i
LUBRICATION POINTS
FRAME
The following is the lubrication points for the frame.
Use grease for parts not listed.
Apply engine oil or grease to cables and movable parts not specified. It will avoid abnormal noise
and damage the durability of the motorcycle.
Grease Grease
Front wheel axle &nut Rea
r
wheel axle &nut
Grease
Side stand pivot
& Main stand pivot

1. GENERAL INFORMATION
1-13
K-XCT 125i
ENGINE

1. GENERAL INFORMATION
1-14
K-XCT 125i
TROUBLESHOOTING
ENGINE WILL NOT START OR IS HARD TO START
Possible cause
1. Check for operation of the fuel pump Abnormal Faulty fuel pump
Normal
2. Inspect the fuel flow Abnormal Faulty pressure regulator
Normal
3. Inspect the fuel injector Abnormal Faulty injector
Normal
4. Perform spark test Weak or no spark Faulty spark plug
Fouled spark plug
Faulty ECU
Good spark Broken or shorted spark plug wire
Faulty ignition switch
Faulty ignition pulse generator
Loose or disconnected spark plug
wire
5. Test cylinder compression Low compression Valve stuck open
Worn cylinder and piston ring
Damaged cylinder head gasket
Compression normal Seized valve
Improper valve timing
6. Starting following normal procedure Engine start Intake pipe leaking
but stops Improper ignition timing (Faulty
ignition coil or ignition pulse
generator)
Engine does not start Fuel contaminated
7. Remove and inspect spark plug Wet plug Throttle valve open
Clogged air cleaner

1. GENERAL INFORMATION
1-15
K-XCT 125i
ENGINE LACKS POWER
Possible cause
1. Raise wheel off the ground Wheels do not Brake dragging
and spin by hand spin freely Worn or damaged wheel bearing
Wheel spins freely
2. Check tire pressure Pressure low Faulty tire valve
Punctured tire
Pressure normal
3. Accelerate lightly Engine speed does Air cleaner dirty
not increase Restricted fuel flow
Clogged muffler
Engine speed increase Pinched fuel tank breather
4. Check ignition timing Incorrect Faulty ECU
Faulty ignition pulse generator
Correct
5. Test cylinder compression Incorrect Valve stuck open
Worn cylinder and piston rings
Leaking head gasket
Normal Improper valve timing
6. Inspect fuel flow Abnormal Faulty pressure regulator
Normal
7. Inspect the fuel injector Abnormal Faulty injector
Normal
8. Remove spark plug Fouled or discolored Faulty spark plug
Not fouled or discolored

1. GENERAL INFORMATION
1-16
K-XCT 125i
Possible cause
9. Check oil level and condition Incorrect Oil level too high
Oil level too low
Contaminated oil
Correct
10. Remove cylinder head cover Valve train not Clogged oil
and inspect lubrication lubricated properly Clogged oil control orifice
Valve train lubricated properly
11. Check for engine overheating Overheating Fan motor not working
Excessive carbon build-up in
combustion chamber
Use of poor quality fuel
Not overheating Wrong type of fuel
Drive and driven pulleys/clutch
slipping
12. Accelerate or run at high Engine knocks Worn piston and cylinder
speed Worn type of fuel
Excessive carbon build-up in
combustion chamber
Ignition timing to advanced
(faulty ECU)
Engine does not knock Lean fuel mixture

1. GENERAL INFORMATION
1-17
K-XCT 125i
POOR PERFORMANCE AT LOW AND IDLE SPEED
Possible cause
1. Check ignition timing Incorrect Improper ignition timing
Correct
2. Inspect the fuel flow Abnormal Faulty pressure regulator
Normal
3. Inspect the fuel injector Abnormal Faulty injector
Normal
4. Check for leaks in the intake pipe Leaking Loose insulator clamp
Damage insulator
No leak
5. Perform spark test Weak or intermittent spark Faulty the spark plug
Faulty carbon or wet fouled spark
plug
Faulty ECU
Faulty ignition coil
Faulty ignition pulse generator
Faulty ignition switch
Loose or disconnected spark plug
wires
Good spark