KYMCO MXU 300 - User manual

By KWANG YANG Motor Co., Ltd.
First Edition, Apr 2005
All rights reserved. Any reproduction or
unauthorized use without the written permission of
KWANG YANG Motor Co., Ltd.
is expressly prohibited.
4121-LCA5/LDE9-S00

PREFACE
This Service Manual describes the
technical features and servicing
procedures for the KYMCO MXU
300/250.
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 19 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 6
CYLINDER HEAD/VALVES 7
CYLINDER/PISTON 8
DRIVE AND DRIVEN PULLEYS 9
FINAL REDUCTION/TRANSMISSION
SYSTEM 10
CRANKCASE/CRANKSHAFT/
BALANCE SHAFT 11
COOLING SYSTEM 12
BRAKE SYSTEM 13
FRONT WHEEL/FRONT
SUSPENSION/STEERING SYSTEM 14
REAR WHEEL/AXLE/SUSPENSION/
DRIVING MECHANISM 15
BATTERY/CHARGING SYSTEM/A.C.
GENERATOR 16
IGNITION SYSTEM 17
STARTING SYSTEM 18
LIGHTS/SWITCHES 19
The information and contents include
d
in this manual may be different from
the vehicle in case specifications are
changed.
CHASSIS
ELECTRICAL
EQUIPMENT
ENGINE

1. GENERAL INFORMATION
1-0
MXU 300/250
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 (OFF ROAD) -------------------------------------- 1-22
TROUBLESHOOTING----------------------------------------------------- 1-26
1

1. GENERAL INFORMATION
1-1
MXU 300/ 250
SERIAL NUMBER
(2) Location of Engine Serial Numbe
r
(1) Location of Frame Serial Numbe
r

1. GENERAL INFORMATION
1-2
MXU 300/250
SPECIFICATIONS (MXU 250)
Model No. LB50
Name & Type MXU 250
Overall length 1810 mm (72.4 in)
Overall width 1050 mm (42 in)
Overall height 1110 mm (44.4 in)
Wheel base 1170 mm (46.8 in)
Engine type O.H.C.
Displacement 249 cm3 (15.2 cu-in)
Fuel Used 92# nonleaded gasoline
Front wheel 112 kg (246 lbs)
Dry weight Rear wheel 102 kg (224 lbs)
Total 214 kg (471 lbs)
Front wheel 116 kg (255 lbs)
Curb weight Rear wheel 110 kg (242 lbs)
Total 226 kg (497 lbs)
Front wheel 22*7-10
Rear wheel 22*10-10
Ground clearance 125 mm (5 in)
Min. turning radius 2900 mm (116 in)
Starting system Electric/Recoil starte
r
Type Gasoline, 4-stroke
Cylinder arrangement Single cylinder
Combustion chamber type Semi-sphere
Valve arrangement O.H.C., chain drive
Bore x stroke 72.7 x 60 mm
(2.9 x 2.4 in)
Compression ratio 10.3:1
Compression pressure 15 kgf/c
m
²(1500kPa,
213 psi)
Open 8.1°BTDC
Intake valve
(at 1 mm lift) Close 41°ABDC
Open 37°BBDC
Exhaust valve
(at 1 mm lift) Close 7.9°ATDC
Valve clearance Intake 0.1 mm (0.004 in)
(cold) Exhaust 0.1 mm (0.004 in)
Idle speed (rpm) 1500rpm
Lubrication type Forced
p
ressure &
Wet sump
Oil pump type Trochoid
Oil filter type Full-flow filtration
Oil capacity 1.6 L (1.4 lmp qt, 1.7
Us qt)
Oil exchanging
capacity 1.4 L (1.23 lmp qt,
1.48 Us q
t
)
Cooling Type Liquid cooled
Air cleaner type & No Wet type element
Fuel capacity 12.5 L (2.63 lmp
gal, 3.25 US gal
Type PTG
Main jet NO. 98
Venturi dia. φ22 mm (
φ
0.88 in)
Throttle type PISTON
Type Full transistor
digital ignition
Ignition timing 5°BTDC/1000rpm
Spark plug DPR7EA-9
Spark plug gap 0.6～0.7mm (0.002
～0.003 in)
Battery Capacity 12V12AH
Clutch type Dry, centrifugal
automatic
Clutch operation system Automatic (V-belt)
Primary reduction system Helical gear/spur
gear
Secondary reduction system Chain drive
Primary reduction ratio 26.5
Secondary reduction ratio 10.02
Reverse ratio 50.9
FR/RR tire rolling
circumference 1759/1759 mm
(71.8/71.8 in)
Fron
t
Tire pressure Rear 0.28 kg/cm²(28
Kpa, 3.2 psi)
Turning Left 40°
angle Right 40°
Fron
t
Disk brake
Brake system type Rear Disk brake
Front Double wishbone
Suspension type Rear Link suspension
Frame type Double cradle
Tires
Fuel S
y
stem
Carbureto
r
Electrical Equipment
I
g
nition S
y
stem
Moving Device
Lubrication S
y
stem
Engine
Drive Train

1. GENERAL INFORMATION
1-3
MXU 300/ 250
SPECIFICATIONS (MXU 300)
Model No. LA60
Name & Type MXU 300
Overall length 1810 mm (72.4 in)
Overall width 1030 mm (41.2 in)
Overall height 1100 mm (44 in)
Wheel base 1170 mm (46.8 in)
Engine type O.H.C.
Displacement 270 cm3 (16.2 cu-in)
Fuel used 92# nonleaded gasoline
Front wheel 110 kg (242 lbs)
Rear wheel 110 kg (242 lbs)
Dry weight Total 220 kg (484 lbs)
Front wheel 115 kg (253 lbs)
Rear wheel 110 kg (242 lbs)
Curb weight Total 225 kg (495 lbs)
Front wheel 22*7-10
Tires Rear wheel 22*10-10
Ground clearance 250 mm (10 in)
Min. turning radius 2900 mm (116 in)
Starting system Electric/Recoil
starter
Type Gasoline, 4-stroke
Cylinder arrangement Single cylinder
Combustion chamber type Semi-sphere
Valve arrangement O.H.C., chain drive
Bore x stroke 72.7 x 65.2 mm
(2.9 x 2.608 in)
Compression ratio 10.3:1
Compression pressure 16 kgf/cm²
(1600kPa, 227 psi)
Opens 5°BTDCIntake valve
(at 1mm lift) Closes 41°ABDC
Opens 37°BBDCExhaust valve
(at 1mm lift) Closes 5°ATDC
Intake 0.1 mm (0.004 in)Valve clearance
(cold) Exhaust 0.1 mm (0.004 in)
Idle speed (rpm) 1600 rpm
Lubrication type Forced pressure &
Wet sump
Oil pump type Trochoid
Oil filter type Full-flow filtration
Oil capacity 1.6 L (1.4 lmp qt,
1.7 Us qt)
Oil exchanging
capacity 1.4 L (1.23 lmp qt,
1.48 Us qt)
Cooling Type Liquid cooled
Air cleaner type & No Wet type element
Fuel capacity 12.5 L (2.63 lmp gal,
3.25USgal
Type PTG
Main jet NO. 98
Venturi dia. φ22 mm (φ0.88 in)
Throttle type PISTON
Type Full transistor digital
ignition
Ignition timing 5°BTDC/1500 rpm
Spark plug DPR7EA-9
Spark plug gap 0.6～0.7mm (0.002
～0.003 in)
Battery Capacity 12V12AH
Clutch type Dry, centrifugal
automatic
Clutch operation system Automatic (V-belt)
Primary reduction system Helical gear/spur
gear/bevel gear
Secondary reduction
system Driven mechanism
High reduction ratio 2.01
Low reduction ratio 3.84
Reverse ratio 3.23
FR/RR tire rolling
circumference 1756/1756 mm
(70.24/70.24 in)
Front
Tire pressure Rear 0.28 kg/cm²(28
Kpa, 3.2 psi)
Left 40°
Turning angle Right 40°
Front Disk brake
Brake system type Rear Disk brake
Front Double wishbone
Suspension type Rear Link suspension
Frame type Double cradle
Engine
Lubrication System
Fuel S
y
stem
Carbureto
r
Electrical Equipment
I
g
nition S
y
stem
Drive Train Moving Device

1. GENERAL INFORMATION
1-4
MXU 300/250
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
MXU 300/ 250
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
MXU 300/250
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.
Confir
m
Capacity

1. GENERAL INFORMATION
1-7
MXU 300/ 250
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.
Snapping!

1. GENERAL INFORMATION
1-8
MXU 300/250
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.
N
o Contact !

1. GENERAL INFORMATION
1-9
MXU 300/ 250
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 tight!
Do not press or
squeeze the wire.

1. GENERAL INFORMATION
1-10
MXU 300/250
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
MXU 300/ 250
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#)
: Caution
: Warning
En
g
ine Oil
Grease
Gear Oil

1. GENERAL INFORMATION
1-12
MXU 300/250
TORQUE VALUES
STANDARD TORQUE VALUES
Item Torque
kgf-m (N-m, lbf-ft) Item Torque kgf-m (N-m, lbf-ft)
5mm bolt and nut
6mm bolt and nut
8mm bolt and nut
10mm bolt and nut
12mm bolt and nut
14mm bolt and nut
0.5 (5, 3.6)
1 (10, 7.2)
2.2 (22, 16)
3.5 (35, 25)
5.5 (55, 40)
7 (70, 50)
4mm screw
5mm screw
6mm screw, SH bolt
6mm flange bolt and nut
8mm flange bolt and nut
10mm flange bolt and nut
0.3 (3, 2.2)
0.4 (4, 2.9)
0.9 (9, 6.5)
1.2 (12, 9)
2.7 (27, 20)
4 (40, 29)
Torque specifications listed below are for important fasteners.
ENGINE
Item Q‘ty Thread dia.
(mm) Torque kgf-m (N-m, lbf-ft) Remarks
Stud bolt
Oil filter screen cap
Seat ball stopper bolt
L cover bolt
Cam shaft holder nut
Tappet ADJ nut
Pivot tensioner bolt
Lifter tensioner bolt
Lifter tensioner cap
Mission case bolt
Mission fill and drain bolt
Driver face nut
Clutch outer nut
Drive plate nut
ACG flywheel nut
Spark plug
Water pump impeller
Oil drain plug
Oil pump screw
Head CYL stud bolt (IN pipe)
Head CYL stud bolt (EX pipe)
A.C.G Startor
Drive bevel gear nut (MXU 300)
Driven bevel gear nut (MXU 300)
4
1
1
10
4
2
1
2
1
9
2
1
1
1
1
1
1
1
1
2
2
3
1
1
8
30
14
6
8
5
8
6
6
8
12
14
12
28
14
12
7
12
3
6
8
5
18
16
0.9 (9, 6.5)
1.5 (15, 11)
4.8 (48, 35)
1.2 (12, 8.6)
2.5 (25, 18)
0.9 (9, 6.5)
1 (10, 7.2)
1.2 (12, 8.6)
0.4 (4, 2.9)
2.7 (27, 20)
2 (20, 15)
9.5 (95, 68)
5.5 (55, 40)
5.5 (55, 40)
6 (60, 43)
1.8 (18, 13)
1.2 (12, 8.6)
2.5 (25, 18)
0.2 (2, 1.5)
0.9 (9, 6.5)
0.9 (9, 6.5)
0.9 (9, 6.5)
10 (100, 72)
10 (100, 72)
Apply oil
Apply oil
Apply oil
Left thread

1. GENERAL INFORMATION
1-13
MXU 300/ 250
FRAME
Item Q‘ty Thread dia.
(mm) Torque K
g
f-
m
(
N-m, lbf-ft
)
Remarks
Steering stem nut
Front swing arm nut
Knuckle ball joint nut
Tie-rod ball joint nut
Front wheel nut
Rear wheel nut
Front wheel hub nut
Rear wheel hub nut
Front shock absorber upper mount bolt
Front shock absorber lower mount bolt
Rear shock absorber upper mount bolt
Rear shock absorber lower mount bolt
Right pivot bolt (MXU 300)
Left pivot bolt (MXU 300)
Left pivot lock nut (MXU 300)
Final gear case mounting bolt
Axle hub holding bolt (MXU 250)
Caliper holder bolt (MXU 250)
Rear wheel shaft nut (MXU 250)
Rear swingarm pivot bolt (MXU 250)
Rear engine upper mounting bolt
Rear engine lower mounting bolt
Front engine mounting bolt
Exhaust muffler lock bolt (frame)
Exhaust muffler lock nut (engine)
Brake caliper mounting bolt
Brake hose oil bolt
Master cylinder holder bolt
1
8
4
4
8
8
2
2
2
2
1
1
1
1
1
8
1
1
2
1
1
1
1
2
2
8
10
4
14
10
12
10
12
12
14
16
10
10
10
10
30
30
30
10
10
6
40
14
10
10
10
8
8
8
10
6
7 (70, 50)
4.5 (45, 32)
3 (30, 22)
2 (20, 15)
4.5 (45, 32)
4.5 (45, 32)
7 (70, 50)
10 (100, 72)
4 (40, 29)
4 (40, 29)
4 (40, 29)
4 (40, 29)
11.8 (118, 85)
1.1 (11, 8)
11.8 (118, 85)
5.5 (55, 40)
4 (40, 29)
1 (10, 7.2)
12 (120, 86)
7 (70, 50)
4 (40, 29)
4 (40, 29)
4 (40, 29)
3.5 (35, 25)
3.5 (35, 25)
3.2 (32, 24)
3.5 (35, 25)
1.2 (12, 8.6)
Castle nut
Castle nut
Castle nut
Castle nut

1. GENERAL INFORMATION
1-14
MXU 300/250
SPECIAL TOOLS
Tool Name Tool No. Remarks
Flywheel puller E003 Flywheel removal
Valve adjuster E012 Valve clearance adjustment
Valve spring compressor E040 Cylinder head disassembly
Oil seal and bearing install E014
Universal holder E017 Drive face/Clutch outer
removal/installation
Flywheel holder E021 Flywheel removal
Clutch spring compressor E034 Driven pulley disassembly
Bearing puller E037
Nut wrench (MXU 300) F013 Left pivot lock nut removal/installation
Pinion puller set (MXU 300) F014 Pinion/Bearing removal
Lock nut wrench (MXU 300) F015 Pinion bearing nut removal
Nut wrench (MXU 250) F010 Rear axle nut removal/installation
Ball join remover F012 Knuckle removal

1. GENERAL INFORMATION
1-15
MXU 300/ 250
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 (SAE10W-30)
•API SG Engine Oil
Transmission gear and rear driving mechanism Gear oil: SAE90#

1. GENERAL INFORMATION
1-16
MXU 300/250
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 ATV.
Steering Column Uppe
r
Throttle Cable
Steering Column Lowe
r
Front Swing Arm Bush
Front Swing Ar
m

1. GENERAL INFORMATION
1-17
MXU 300/ 250
Sprocket hub/Rea
r
Axle Hub Collar/Oil
Seal/Bearin
g
Driven Sprocket
Rear Swing Ar
m
Axle