KYMCO ZX/SCOUT 50 User manual

ZX / SCOUT
PREFACE
This Service Manual describes the technical feature.s and servicing
procedures for the KYMCO ZX / SCOUT 50.
In this manual, many illustrations and drawings are used to help
servicemen have better understanding.
Section 2 contains the service precautions for all operations and
troubleshooting stated in this manual. Read them carefully before
starting any operation.
Section 3 describes the inspection/adjustment procedures, safety rules and
service information for each part, starting from periodic maintenance.
Sections 4 through 16 give instructions for disassembly, assembly and
inspection of lubrication system, engine, fuel system and electrical
equipment.
Section 17 is the maintenance and inspection directions for the evaporative/
exhaust emission control system. 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
MARCH 2000

1. SPECIFICATIONS
1-0
ZX / SCOUT
1 TABLE OF CONTENTS
SPECIFICATIONS......................................................................................... 1
GENERAL INFORMATION......................................................................... 2
INSPECTION/ADJUSTMENT...................................................................... 3
LUBRICATION SYSTEM............................................................................. 4
ENGINE REMOVAL/INSTALLATION...................................................... 5
CYLINDER HEAD/CYLINDER/PISTON................................................... 6
A.C. GENERATOR......................................................................................... 7
KICK STARTER/DRIVE PULLEY/CLUTCH/DRIVEN PULLEY......... 8
FINAL REDUCTION ..................................................................................... 9
CRANKCASE/CRANKSHAFT.....................................................................10
CARBURETOR...............................................................................................11
FRAME COVERS...........................................................................................12
STEERING HANDLEBAR/FRONT WHEEL/FRONT BRAKE/
FRONT SHOCK ABSORBER/FRONT FORK...........................................13
REAR WHEEL/REAR BRAKE/REAR SHOCK ABSORBER.................14
ELECTRICAL EQUIPMENT.......................................................................15
INSTRUMENT/SWITCHES/LIGHTS.........................................................16
EVAPORATIVE/EXHAUST EMISSION CONTRAL SYSTEM .............17
1

1. SPECIFICATIONS
1-1
ZX 50
SPECIFICATIONS
Name & Model SC10AS
Overall length (mm) 1792
Overall width (mm) 690
Overall height (mm) 1053
Wheel base (mm) 1225
Engine type Air cooled 2-stroke
Displacement (cc) 49.4 cc
Net weight (kg)
92.5
Seating capacity 2 riders (110kg)
Gross weight(kg)
150
Front wheel 120/70-12
Tires Rear wheel 120/70-12
Ground clearance (mm) 170
Braking distance (m)
(Initial speed Km/h) 7m (30km/h)
Min. turning radius (mm) 1940
Starting system Starting motor &
kick starter
Fuel type Gasoline, 2-stroke
motor oil
Cylinder arrangement Single cylinder, flat
Combustion chamber type Semi-sphere
Valve arrangement Reed valve & piston
Bore x stroke (mm) 39 x 41.4
Compression ratio 7.3 : 1
Compression pressure
(kg/cm²rpm) 11.5kg/cm²
Max. output (kw/rpm) 3.75/7000kw/rpm
Max. torque (kg-m/rpm) 4.5/6500 kg m/rpm
Open
Automatic controlled
Intake Close Automatic controlled
Port Open ⎯
timing Exhaust Close ⎯
Open ⎯
Scavenge Close ⎯
Idle speed (rpm) 2100±100
Lubrication type Separate type
Oil pump type Plunger type
Oil filter type Full-flow filtration
Lubrication oil capacity (liter) 0.80
Air cleaner type & No. Wet, single
Fuel capacity (liter) 4.9
Type Plunger type
Carburetor Piston dia. (mm) ⎯
Venturi dia. (mm) 14
Ignition system type CDI electromagnetic
Ignition
Ignition timing F mark 15.5°±2°BTDC/2000rpm
Spark NGK BR8HSA
plug ND ¯
Spark plug gap (mm) 0.60.7
Battery capacity 12V3AH
Power to transmission gear Power-transmission
gear-clutch
Reduction ratio of power to
transmission ⎯
Clutch type Dry multi-disc clutch
Transmission gear operation
type Automatic centrifugal
type
Transmission ratio 1 speed ⎯
Reduction Type Two-stage reduction
gear 1st reduction ratio ⎯
2nd reduction ratio ⎯
Transmission gear type Non-stage transmission
Tire
p
ressure Front wheel 1.50 1.75
(kg/cm²) Rear wheel 1.75 2.25
Turning angle Right & left 45°
Brake s
y
ste
m
Front wheel Ex
p
andin
g
/h
y
draulic
type Rear wheel Expanding
Sus
p
ension Front wheel Telesco
p
e
type Rear wheel Unit swing
Shock absorbe
r
Front wheel Telescope
type Rear wheel Unit swing
Frame type Pipe under bone
CO 4.5%Exhaust
emission
concentration HC 7000ppm Max

2. GENERAL INFORMATION
2-0
ZX / SCOUT
1
__________________________________________________________________________________
2
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
GENERAL INFORMATION
__________________________________________________________________________________
ENGINE SERIAL NUMBER/IDENTIFICATION............................. 2- 1
SERVICE PRECAUTIONS................................................................. 2- 2
SERVICE INFORMATION ................................................................ 2- 6
TORQUE VALUES............................................................................. 2- 8
SPECIAL TOOLS................................................................................ 2- 9
LUBRICATION POINTS.................................................................... 2-11
WIRING DIAGRAM........................................................................... 2-12
CABLE & HARNESS ROUTING....................................................... 2-13
TROUBLESHOOTING ....................................................................... 2-17

2. GENERAL INFORMATION
2-1
ZX / SCOUT
ENGINE SERIAL NUMBER/IDENTIFICATION
Location of Engine Serial Numbe
r

2. GENERAL INFORMATION
2-2
ZX / SCOUT
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.
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.

2. GENERAL INFORMATION
2-3
ZX / SCOUT
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.
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.
Easy confirm
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.

2. GENERAL INFORMATION
2-4
ZX / SCOUT
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.
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.
Don’t touch

2. GENERAL INFORMATION
2-5
ZX / SCOUT
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.
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.)
Engine Oil
: Apply grease for lubrication.
Grease
: Use special tool.
Special

: Caution
: Warning
(Ö12-3) :Refer to page 12-3.
Remove the rest

2. GENERAL INFORMATION
2-6
ZX / SCOUT
SERVICE INFORMATION
ENGINE Standard (mm) Service Limit (mm)
Item SC10AS SC10AS
Cylinder head warpage ⎯0.10
Piston O.D.(5mm from bottomof piston skirt) 38.95538.970 38.90
Cylinder-to- piston clearance 0.10
Piston pin hole I.D. 12.00212.008 12.03
Piston pin O.D. 11.99412.0 11.98
Piston-to-piston pin clearance ←←
Piston ring end gap (top/second) 0.100.25 0.40
Connecting rod small end I.D. 17.00517.017 17.03
Cylinder bore 39.039.025 39.05
Drive belt width 18 17
Drive pulley collar O.D. 20.0120.025 ←
Movable drive face ID. 20.03520.085 19.97
Weight roller O.D. 13.0 12.4
Clutch outer I.D. 107107.2 107.5
Driven face spring free length 87.9 82.6
Driven face O.D. ←←
Movable driven face I.D. ←←
Connecting rod big end side clearance ←←
Connecting rod big end radial clearance ←←
Crankshaft runout A/B ⎯←
CARBURETOR SC10AS
Venturi dia. 14mm
Identification number 014A
Float level 5.0mm
Main jet #80
Slow jet #35
Air screw opening 1 ±¼
Idle speed 2100±100rpm
Throttle grip free play 26mm
Jet needle clip notch 1st notch

2. GENERAL INFORMATION
2-7
ZX / SCOUT
FRAME Standard (mm) Service Limit (mm)
Item SC10AS SC10AS
Axle shaft runout ⎯0.2
Radial
Front wheel rim runout Axial
Front shock absorber spring free length 200.0 182.8
Rear wheel rim runout 2.0
Brake drum I.D. Front/rear 110 111
Brake lining thickness Front/rear 4.0/4.0 2.0/2.0
Brake disk runout Front/rear ⎯0.30
Rear shock absorber spring free length 235.7 218.7
ELECTRICAL EQUIPMENT SC10AS
Capacity 12V3AH
Voltage 13.013.2V
Charging Standard 0.4A/5H
Battery
current Quick 4A/0.5H
Spark plug (NGK) BR8HSA
Spark plug gap 0.60.7mm
Primary coil 0.1530.187Ω
Secondary coil
(with plug cap) 6.9910.21KΩ
Ignition coil resistance Secondary coil
(without plug cap) 3.243.96KΩ
Pulser coil resistance (20) 80160Ω
Ignition timing 15.5°±2°BTDC/2000rpm

2. GENERAL INFORMATION
2-8
ZX / SCOUT
TORQUE VALUES
ENGINE
Ite
m
Thread dia. (mm) Torque (k
g
-m) Remarks
Cylinder head bolt
Clutch drive plate nut
Clutch outer nut
Drive face nut
Oil check bolt
Engine mounting bolt
Engine hanger bracket bolt
Exhaust muffler joint lock nut
Exhaust muffler lock bolt
Spark plug
BF7x115
10
NH10
NH12
10
BF10x95
BF10x50
NC6mm
BF8x35
1.51.7
3.54.0
3.54.5
5.06.0
1.01.5
4.55.5
3.54.5
1.01.4
3.03.6
1.11.7
(cold)
(cold)
FRAME
Ite
m
Thread dia. (mm) Torque (k
g
-m) Remarks
Handlebar lock nut
Steering stem lock nut
Steering top cone race
Front axle nut
Rear axle nut
Rear brake arm bolt
Front shock absorber:
upper mount bolt
lower mount bolt
hex bolt
Front damper nut
Front pivot arm bolt
Rear shock absorber:
upper mount bolt
lower mount bolt
lower joint nut
10
25.4
25.4
12
16
8
8
10
8
8
4.55.0
8.012.0
0.51.3
5.07.0
11.013.0
3.3
3.3
1.53.0
1.53.0
3.54.5
2.43.0
1.52.5
Flange bolt/U-nut
Flange U-nut
Flange U-nut
Flange nut
Flange bolt/U-nut
Cross head
Apply locking agent
Flange screw/U-nut
Flange nut
Torque specifications listed above are for important fasteners. Others should be tightened to
standard torque values below.
STANDARD TORQUE VALUES SH bolt: 8mm Flange 6mm
bolt
Ite
m
Torque (k
g
-m) Ite
m
Torque (k
g
-m)
5mm bolt, nut
6mm bolt, nut
8mm bolt, nut
10mm bolt, nut
12mm bolt, nut
0.450.6
0.81.2
1.82.5
3.04.0
5.06.0
5mm screw
6mm screw, SH bolt
6mm flange bolt, nut
8mm flange bolt, nut
10mm flange bolt, nut
0.350.5
0.71.1
1.01.4
2.43.0
3.54.5

2. GENERAL INFORMATION
2-9
ZX / SCOUT
SPECIAL TOOLS
Tool Name Tool No. Remarks
Universal bearing puller E030 Crankshaft bearing removal
Lock nut socket wrench F001 Top cone race holding
Lock nut wrench, F002 Stem lock nut tightening
Crankcase puller E026 Crankcase disassembly
Bearing remover set, 12mm
(Spindle assy, 12mm)
(Remover weight)
E020 Drive shaft bearing removal/installation
Bearing remover set, 15mm
(Spindle assy, 15mm)
(Remover head, 15mm)
(Remover shaft, 15mm)
E018 Drive shaft bearing removal/installation
Bearing outer driver, 28x30mm E014 Bearing installation
Clutch spring compressor E027 Driven pulley disassembly/assembly
Crankcase assembly collar E023 Driven shaft, crankshaft & crankcase
assembly
Crankcase assembly tool E024 Crankshaft & crankcase assembly
Ball race remover F005 Steering stem bearing races
Rear shock absorber compressor F004 Rear shock absorber disassembly/assembly
Universal holder E017 Flywheel holding
Flywheel puller E001 Flywheel removal
Bearing outer driver, 32x35mm E014 Drive shaft bearing installation
Final shaft bearing installation
Bearing outer driver, 37x40mm E014 Drive shaft bearing installation Final
shaft bearing installation Crankshaft
bearing installation
Universal bearing puller E030 Crankshaft bearing removal

2. GENERAL INFORMATION
2-10
ZX / SCOUT
LUBRICATION POINTS
ENGINE
NO. Lubrication Points Lubricant Remarks
1 Crankcase sliding & movable JASO-FC or API-TC
2 Cylinder movable parts JASO-FC or API-TC
3 Transmission gear (final gear) SAE-90#
4 Kick starter spindle bushing Grease
5 Drive pulley movable parts Grease
6 Starter pinion movable parts Grease
FRAME
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.
Rear Brake Cable
Front/Rear Brake Lever
Seat Loc
k
Rear Wheel Bearing
Throttle Cable
Main Stand Pivot
Grease
Engine Oil Grease
Engine Oil
Speedometer Gear/
Brake Cam/Front
Shock Absorber
Lower Mount
Bushings/Pivot
Grease
Grease
Grease Engine Oil
Brake Cam/
Anchor Pin
Grease

2. GENERAL INFORMATION
2-11
ZX / SCOUT
SC10AS WIRING DIAGRAM

2. GENERAL INFORMATION
2-12
ZX / SCOUT
CABLE & HARNESS ROUTING
Front Brake Reservoi
r
Rear Brake Cable
Throttle Cable
Ignition Switch
Regulator/Rectifie
r
Front Brake Fluid Tube
Resisto
r
Front Stop Switch Wire
Speedometer Cable
Speedometer Cable
Front Brake Fluid Tube
Horn
Rear Stop Switch Wire

2. GENERAL INFORMATION
2-13
ZX / SCOUT
Wire Harness
Rear Brake Cable
Throttle Cable
Front Brake Fluid Tube
Speedometer Cable
Speedometer Cable
Front Brake Fluid Tube

2. GENERAL INFORMATION
2-14
ZX / SCOUT
Fuel Unit
Ignition Coil
Fuel Filte
r
Oil Tank Cap
Starter Relay
CDI Unit
Battery
Wire Harness
Ignition Coil
Oil Tube

2. GENERAL INFORMATION
2-15
ZX / SCOUT
Fuel Unit
Fuel Tank Cap
Vacuum Tee
Oil Pump
Ignition Coil
Oil Tube

2. GENERAL INFORMATION
2-16
ZX / SCOUT
TROUBLESHOOTING
ENGINE WILL NOT START OR IS HARD TO START
cEmpty fuel tank
dClogged float valve
eClogged fuel filter
fFaulty auto fuel valve
cFaulty spark plug
dFouled spark plug
eFaulty CDI unit
fFaulty A.C. generator
gBroken or shorted ignition coil
hBroken or shorted exciter coil
iFaulty ignition switch
cBurned or worn cylinder
piston
dFaulty reed valve
eBlown cylinder head gasket
fLeaking crankcase
gFaulty crankcase oil seal
cIncorrectly adjusted idle speed
dAir leaking through intake
pipe
eIncorrect ignition timing
cFlooded carburetor
dThrottle valve excessively
open
cFaulty auto bystarter
Check if fuel reaches
carburetor by loosening
drain screw.
Remove spark plug and
install it into spark plug
cap to test spark by
connecting it to engine
ground.
Inspection/Adjustment
Fuel reaches
carburetor
Spark jumps
Dry spark plug
Not clogged
Normal
compression
Engine does not
fire
Fuel does not
reach carburetor
Weak or no spark
Wet spark plug
Clogged
Low or no
compression
Engine fires but
does not start
Test cylinder
compression.
Start engine by
follow-ing normal
startin
g
p
rocedure.
Wait for 30 minutes and
then remove the
carbu-retor auto choke
circuit hose and blow
the hose with mouth.
Remove spark plug and
inspect again.
Probable Cause
Symptom