KYMCO NEXXON 50 User manual

NEXXON 50
PREFACE
This Service Manual describes the
technical features and servicing
procedures for the KYMCO NEXXON
50.
Section 1 contains the precautions for all
operations stated in this manual. Read
them carefully before starting any
operation.
Section 2 is the inspection/ adjustment
procedures, safety rules and service
information for each part, starting from
periodic maintenance.
Sections 3 and 4 state the servicing
procedures and cautions for the removal
and installation of lubrication and fuel
systems.
Sections 5 through 18 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
INSPECTION/ADJUSTMENT 2
LUBRICATION SYSTEM 3
FUEL SYSTEM 4
ENGINE REMOVAL/INSTALLATION 5
CYLINDER HEAD/VALVES 6
CYLINDER/PISTON 7
ALTERANTOR/CAM CHAIN
TENSIONER 8
CLUTCH/GEAR SHIFT MECHANISM 9
ENGINE
CRANKCASE/CRANKSHAFT/KICK
STARTER/TRANSMISSION 10
FRONT WHEEL/SUSPENSION/
STEERING 11
REAR WHEEL/BRAKE/SUSPENSION 12
HYDRAULIC BRAKE 13
CHASSIS
FRAME COVER 14
IGNITION SYSTEM 15
CHARGING SYSTEM 16
STARTING SYSTEM 17
LIGHTS/INSTRUMENTS/SWITCHES
/
HORN/FUEL UNIT 18
ELECTRICAL EQUIPMENT
EXHAUST EMISSION CONTROL
SYSTEM 19
Our company reserves right to make
any alteration in the design. The
information and contents included in
this manual may be different from the
motorcycle in case specifications are
changed.

1. GENERAL INFORMATION
1-0
NEXXON 50
1
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
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GENERAL INFORMATION
__________________________________________________________________________________
ENGINE SERIAL NUMBER---------------------------------------------- 1- 1
SPECIFICATIONS---------------------------------------------------------- 1- 2
SERVICE PRECAUTIONS------------------------------------------------ 1- 3
TORQUE VALUES --------------------------------------------------------- 1-11
SPECIAL TOOLS ----------------------------------------------------------- 1-12
LUBRICATION POINTS -------------------------------------------------- 1-13
CABLE & HARNESS ROUTING ---------------------------------------- 1-14
WIRING DIAGRAM-------------------------------------------------------- 1-18
TROUBLESHOOTING----------------------------------------------------- 1-19
1

1. GENERAL INFORMATION
1-1
NEXXON 50
ENGINE SERIAL NUMBER
Location of Engine Serial Numbe
r
Location of Frame Serial Numbe
r
Location of Engine Serial Numbe
r
Location of Frame Serial Numbe
r

1. GENERAL INFORMATION
1-2
NEXXON 50
SPECIFICATIONS
Motorcycle name & Model No. LFA3
Motorcycle name NEXXON 50
Overall length (mm) 1975
Overall width (mm) 710
Overall height (mm) 1125
Wheel base (mm) 1285
Engine type 4∞
Displacement (cc) 49
Fuel type nonleaded gasoline
Front wheel 46.5
Rear wheel 58
Dry weight (kg)
Front wheel 48.5
Rear wheel 63.5
Gross weight(kg)
Front wheel 2.5-17
Tires Rear wheel 2.75/17
Ground clearance (mm) 120
Braking distance (m) 7under
Perform-
ance Min. turning radius
(mm) 3800(R/L)
Starting system Starting motor &
kick starter
Type OHC
Cylinder arrangement Single cylinder
Combustion chamber type Semi-sphere
Valve arrangement Single cam, OHC
Bore x stroke (mm) φ52.4x 49.5
Compression ratio 8
Compression pressure
(kg/cm²)13
Max. output 1.8/7000kw(r/min)
Max. torque 2.6/4500kgm/rpm
Open 0°
Intake
(1mm) Close 35°
Engine
Open 30°
Port
timin
g
Exhaust
(1mm) Close 5°
Intake 0.02mm
Valve clearanc
e
(cold) Exhaust 0.02mm
Idle speed (rpm) 1700rpm
Lubrication type Forced
p
ressure &
wet sump
Oil pump type Inner/Outer rotor
Oil filter type Wire gauze filter
Lubrication System
Oil capacity 0.9 liter
Cooling Type Air cooling
Air cleaner type Wet, single
Fuel capacity 4liter
Type PIF
Piston dia. (mm) 13
Venturi dia.(mm) φ11equivalent
Fuel System
Carburetor
Throttle type Plunger type
Type CDI
Ignition timing 15±2°/1700rpm
Spark plug CHAMPION-P-PZ9HC
Ignition System
Spark plug gap 0.6～0.7mm
Electrical Equipment
Battery Capacity 12V5AH
Clutch Type Wet multi-disc clutch
Type Permanent gear meshing
Operating method Foot operated
Type Cycle type
1st gear 2.92
2nd gear 1.67
3rd gear 1.17
4th gear 0.92
Power Drive System
Transmission Gear
Reduction
ratio
5th gear -------
Front Caster angle 27°
Axle Wheel base 1305
Tire
p
ressure Front 1.75
(k
g
/c
m
²)(2 riders) Rear 2.25
Left 45°
Turning angle Right 45°
Front Disk brake
Brake system
type Rear Drum brake
Front Telescope
Damping Device
Shock absorber
type Rear Mono Shock
Frame type Back bone
Moving Device

1. GENERAL INFORMATION
1-3
NEXXON 50
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
1-4
NEXXON 50
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
1-5
NEXXON 50
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
1-6
NEXXON 50
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
1-7
NEXXON 50
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
1-8
NEXXON 50
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 o
r
squeeze the wire.