Sym Jet Sport X S50, Jet Sport X R50, Jet Sport X SR50 Service Manual

SERVICE MANUAL

S50/R50/SR50

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How to use this manual

Contents

Model illustration

Forward

This service manual contains the technical data of each component inspection and
repair for the SANYANG Jet Sport X S50 / R50 / SR50 series scooters.

The manual is shown with illustrations and focused on “Service Procedures”,
“Operation Key Points”, and “Inspection Adjustment” so that provides technician
with service guidelines.

If the style and construction of the scooters, Jet Sport X S50 / R50 / SR50 series,
are different from that of the photos, pictures shown in this manual, the actual
vehicle shall prevail. Specifications are subject to change without notice.

Service Department

Sanyang Industry Co., LTD.

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Contents

How to Use This Manual

This service manual describes basic information of different system parts and
system inspection & service for SANYANG Jet Sport X S50 / R50 / SR50 series
scooters. In addition, please refer to the manual contents in detailed for the model
you serviced in inspection and adjustment.

The first chapter covers general information and trouble diagnosis.
The second chapter covers service maintenance information.
The 3rd to the 10th chapters covers engine and driving systems.
The 11th to the 14th chapters is contained the parts set of frame body.
The 15th chapter is electrical equipment.
The 16th chapter is wiring diagram.

Please see index of content for quick
having the special parts and system
information.

All information, illustration, directions and specifications included in this manual are
current as at the time of publication. SANYANG reserves the rights to make
changes at any time without prior notice and without incurring any obligation
whatever. Without written consent by SANYANG can not copy any part of this
manual.

There are 4 buttons, "Forward", "How to use this manual", "Mechanism

Illustrations", and "Contents" on the CD-R version, and can be access to these

items by click the mouse.
If user wants to look for the content of each chapter, selecting the words of each
chapter on the main contents can reach to each chapter. There are two buttons,
Back to homepage and Main contents, onto the top line of first page of the each
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buttons to back the homepage or main contents. The content of each chapter
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the top line of each page so that clicking the button can back to the contents of
this chapter.

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Contents

Contents

Page Content Index

1-1 ~ 1-18

General Information

1

2-1 ~ 2-14

Service Maintenance Information

2

3-1 ~ 3-6

Lubrication System

3

4-1 ~ 4-10

Fuel System

4

5-1 ~ 5-6

Engine Removal

5

6-1 ~ 6-4

Cylinder Head / Cylinder / Piston

6

7-1 ~ 7-14

A.C. Generator

7

8-1 ~ 8-6

"V" Type Belt Driving System / Kick-Starter

8

9-1 ~ 9-6

Final Driving Mechanism

9

10-1 ~ 10-10

Crankcase / Crankshaft

10

11-1 ~ 11-12

Body Cover

11

12-1 ~ 12-12

Brake System

12

13-1 ~ 13-10

Steering / Front Wheel / Shock absorber

13

14-1 ~ 14-4

Rear Wheel / Shock absorber

14

15-1 ~ 15-22

Electrical Equipment

15

16-1 ~ 16-4

Electrical Diagram

16

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Model illustration

Jet Sport X S50 / R50 / SR50 Series

Headlight

Front brake lever

Rear brake lever

Taillight

Helmet hook

Fuel tank cap

Engine number

Luggage box

Muffler

Battery / Fuses / C.D.I. /
Eng. Oil tank cap

ENG. Stop / Starter switch

High & Low beam / Passing /
Turn signal / Horn switch

Air cleaner

Frame number

Front turn signal

Ignition switch

Rear turn signal

Seat lock

Rear turn signal

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Contents

1. General Information

1-1

Symbols and Marks·····················1-1
General Safety······························1-2
Service Precautions·····················1-3
Specifications·······························1-6

Torque values·······························1-7
Cables and Harness Routing······1-9
Troubleshooting···························1-13
Lubrication Points ·······················1-20

Symbols and Marks

Symbols and marks are used in this manual to indicate what and where the special service are needed,
in case supplemental information is procedures needed for these symbols and marks, explanations will
be added to the text instead of using the symbols or marks.

Warning

Means that serious injury or even death may result if procedures are not
followed.

Caution

Means that equipment damages may result if procedures are not
followed.

Engine oil

Limits to use SAE 20 JASO FC class oil. Warranty will not cover the
damage that caused by not apply with the limited engine oil.
(Recommended oil: MAX-2 serial oils)

Grease King Mate G-3 is recommended.

Gear oil

King Mate gear oil serials are recommended. (Bramax HYPOID GEAR
OIL # 140)

Locking sealant

Apply sealant; medium strength sealant should be used unless otherwise
specified.

Oil seal Apply with lubricant.

Renew Replace with a new part before installation.

Brake fluid Use recommended brake fluid DOT3 or WELLRUN brake fluid.

Special tools Special tools.

O

Correct Meaning correct installation.

X

Wrong Meaning wrong installation.

Indication Indication of components.

Directions Indicates position and operation directions.

Components assembly directions each other.
Indicates where the bolt installation direction, --- means that bolt cross

through the component (invisibility).

1

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Contents

1. General Information

1-2

General Safety

Carbon monoxide

If you must run your engine, ensure the place is
well ventilated. Never run your engine in a closed
area. Run your engine in an open area, if you
have to run your engine in a closed area, be sure
to use an extractor.

Caution

Exhaust contains toxic gas which may cause
one to lose consciousness and even result in
death.

Gasoline

Gasoline is a low ignition point and explosive
material. Work in a well-ventilated place, no flame
or spark should be allowed in the work place or
where gasoline is being stored.

Caution

Gasoline is highly flammable, and may explode
under some conditions, keep it away from
children.

Used engine oil

Caution

Prolonged contact with used engine oil (or
transmission oil) may cause skin cancer
although it might not be verified.

We recommend that you wash your hands with
soap and water right after contacting. Keep the
used oil beyond reach of children.

Hot components

Caution

Components of the engine and exhaust system
can become extremely hot after engine
running. They remain very hot even after the
engine has been stopped for some time. When
performing service work on these parts, wear
insulated gloves and wait until cooling off.

Battery

Caution

•

Battery emits explosive gases; flame is
strictly prohibited. Keeps the place well
ventilated when charging the battery.

•

Battery contains sulfuric acid (electrolyte)
which can cause serious burns so be careful
do not be spray on your eyes or skin. If you
get battery acid on your skin, flush it off
immediately with water. If you get battery
acid in your eyes, flush it off immediately
with water and then go to hospital to see an
ophthalmologist.

•

If you swallow it by mistake, drink a lot of
water or milk, and take some laxative such
as castor oil or vegetable oil and then go to
see a doctor.

•

Keep electrolyte beyond reach of children.

Brake shoe

Do not use an air hose or a dry brush to clean
components of the brake system, use a vacuum
cleaner or the equivalent to avoid dust flying.

Caution

Inhaling dust may cause disorders and cancer
of the breathing system.

Brake fluid

Caution

Spilling brake fluid on painted, plastic, or rubber
parts may cause damage to the parts. Place a
clean towel on the above-mentioned parts for
protection when servicing the brake system.
Keep the brake fluid beyond reach of children.

This chapter Contents

1. General Information

1-3

Service Precautions

•

Always use with SANYANG genuine parts and
recommended oils. Using non-designed parts
for SANYANG scooter may damage the
scooter.

•

Special tools are designed for remove and
install of components without damaging the
parts being worked on. Using wrong tools may
result in parts damaged.

•

When servicing this scooter, use only metric
tools. Metric bolts, nuts, and screws are not
interchangeable with the English system, using
wrong tools and fasteners may damage this
vehicle.

•

Clean the outside of the parts or the cover
before removing it from the scooter. Otherwise,
dirt and deposit accumulated on the part's
surface may fall into the engine, chassis, or
brake system to cause damage.

•

Wash and clean parts with high ignition point
solvent, and blow dry with compressed air. Pay
special attention to O-rings or oil seals
because most cleaning agents have an
adverse effect on them.

•

Never bend or twist a control cable to prevent
stiff control and premature worn out.

•

Rubber parts may become deteriorated when
old, and prone to be damaged by solvent and
oil. Check these parts before installation to
make sure that they are in good condition,
replace if necessary.

•

When loosening a component which has
different sized fasteners, operate with a
diagonal pattern and work from inside out.
Loosen the small fasteners first. If the bigger
ones are loosen first, small fasteners may
receive too much stress.

•

Store complex components such as
transmission parts in the proper assemble
order and tie them together with a wire for
ease of installation later.

•

Note the reassemble position of the important
components before disassembling them to
ensure they will be reassembled in correct
dimensions (depth, distance or position).

•

Components not to be reused should be
replaced when disassembled including gaskets
metal seal rings, O-rings, oil seals, snap rings,
and split pins.

Caution

In addition to damaging paint finish, brake oil
can also damage the structural integration of
plastic or rubber parts.

1. General Information

1-4

•

The length of bolts and screws for assemblies,
cover plates or boxes is different from one
another, be sure they are correctly installed. In
case of confusion, Insert the bolt into the hole
to compare its length with other bolts, if its
length out side the hole is the same with other
bolts, it is a correct bolt. Bolts for the same
assembly should have the same length.

•

Tighten assemblies with different dimension
fasteners as follows: Tighten all the fasteners
with fingers, then tighten the big ones with
special tool first diagonally from inside toward
outside, important components should be
tightened 2 to 3 times with appropriate
increments to avoid warp unless otherwise
indicated. Bolts and fasteners should be kept
clean and dry. Do not apply oil to the threads.

•

When oil seal is installed, fill the groove with
grease, install the oil seal with the name of the
manufacturer facing outside, check the shaft
on which the oil seal is to be installed for
smoothness and for burrs that may damage
the oil seal.

•

Remove residues of the old gasket or sealant
before reinstallation, grind with a grindstone if
the contact surface has any damage.

•

The ends of rubber hoses (for fuel, vacuum, or
coolant) should be pushed as far as they can
go to their connections so that there is enough
room below the enlarged ends for tightening
the clamps.

•

Rubber and plastic boots should be properly
reinstalled to the original correct positions as
designed.

•

The tool should be pressed against two (inner
and outer) bearing races when removing a ball
bearing. Damage may result if the tool is
pressed against only one race (either inner
race or outer race). In this case, the bearing
should be replaced. To avoid damaging the
bearing, use equal force on both races.

Both of these examples can result in bearing
damage.

•

Lubricate the rotation face as assembling.
Check if positions and operation for installed
parts is in correct and properly.

Boots

Manufacturer's name

1. General Information

1-5

1. General Information

1-6

Specifications

Make SANYANG MODEL Jet Sport X 50 series

Overall Length 1840 mm Front Telescopic Fork

Overall Width 690 mm

Suspension

System

Rear Unit Swing

Overall Height 1120 mm Front 120 / 70 – 12

Dimension

Wheel Base 1275 mm

Tire

Specifications

Rear 130 / 70 – 12

Front 42 kg Front Disk (Ø190mm)

Rear 56 kg Disk (Ø160mm)

Curb

Weight

Total 98 kg

Brake System

Rear

DRUM (Ø110mm)

Passengers /

One / 75 kg Max. Speed 48 km/hr Below

Front 64 kg Climb Ability 22° Below

Rear 109 kg Primary Reduction BELT

Weight

Total Weight

Total 173 kg Secondary Reduction

GEAR

Type Gasoline Clutch Centrifugal, dry type

Installation and

arrangement

Horizontal, below center,

incline

Forman Perce

Transmission C.V.T.

Fuel Used Unleaded (92/95) Speedometer 0 ~ 80 km/hr

Cycle/Cooling 2-stroke/forced air cooled

Horn 93 ~ 112 dB/A

Bore Ø 39 mm Muffler

Expansion & Pulse

Type

Stroke 41.4 mm

Exhaust Pipe Position and

Direction

Right side, and

Backward

Cylinder

Number/Arrang

ement

Single Cylinder Lubrication System Separated-lubrication

Displacement 49.4 cc

Compression Ratio

7.2 : 1

CO

1.0 g/km ↓

Max. HP 2.6 kw / 6000 rpm

Exhaust

Concentration

HC+Nox

1.2 g/km ↓

Max. Torque 4.2 Nm / 5500 rpm E.E.C. X

Ignition C.D.I. P.C.V. X

Engine

Starting System Electrical & kick

Catalytic reaction control

system

○

1. General Information

1-7

Torque values

Standard Torque Values for Reference

Type Torque value Type Torque value

5 mm Bolt, nut 0.45 ~ 0.6kgf-m 5 mm Screw 0.35 ~ 0.5kgf-m
6 mm Bolt, nut 0.8 ~ 1.2kgf-m

6 mm Screw, flange bolt
(SH Type)

0.7 ~ 1.1kgf-m

8 mm Bolt, nut 1.8 ~ 2.5kgf-m 8 mm Flange bolt, nut 1.0 ~ 1.4kgf-m
10 mm Bolt, nut 3.0 ~ 4.0kgf-m 8 mm Flange bolt, nut 2.4 ` 3.0kgf-m
12 mm Bolt, nut 5.0 ~ 6.0kgf-m 10 mm Flange bolt, nut 3.5 ~ 4.5kgf-m

The torque values listed in below table are for more important tighten torque values. Please see above
standard values for not listed in the table.

Engine

Item Q’ty

Thread Dia.

(mm)

Torque Value

(kgf-m)

Remarks

Cylinder head bolt 4 7 1.6~2.0 When engine cooled
Spark plug 1 14 1.1~1.7
Inlet pipe nut 2 6 0.8~1.2
Flywheel nut 1 10 3.5~4.5
Movable drive face nut 1 12 5.5~6.5
Drive plate nut 1 28 5.0~6.0
Clutch outer nut 1 10 3.5~4.5
Mission oil check bolt 1 10 1.0~1.5
Mission oil drain bolt 1 8 1.0~1.5
Mission cover bolt 7 8 2.4~3.0
Crankcase bolts 6 6 1.0~1.5
Cooling fan bolts 4 6 0.6~1.0
Brake shoe anchor pin 1 8 1.5~2.0
Nuts for exhaust pipe 2 6 1.0~1.4
Mounting bolts for exhaust 2 8 3.0~3.6
Others - 6 0.8~1.2

1. General Information

1-8

Frame

Item Q’ty

Thread Dia.

(mm)

Torque Value

(kgf-m)

Remarks

Mounting nut for handle 1 10 4.0~5.0

Steering stem lock nut 1 25.4 1.0~2.0

Steering top cone race 1 25.4 0.2~0.3
Front cushion bolts 4 8 2.4~3.0
Front wheel axle nut 1 12 5.0~7.0
Air cleaner bolts 2 6 1.0~1.4
Brake master cylinder mounting bolts

4 6 1.0~1.4

Brake hose bolts 2 10 3.3~3.7
Brake caliper mounting bolts 2 10 3.1~3.5
Brake shoe guide bolts 2 6 1.5~2.0
Brake shoe guide bolts cap 2 6 0.8~1.2
Brake drain valve 1 6 0.8~1.0
Mounting bolt for brake disc 7 8 4.0~4.5
Rear brake arm bolts 1 5 0.8~1.2
Rear brake lever nuts 2 5 0.8~1.2
Bolt for engine hanger 4 12 5.5~6.5
Bolt for engine hanger bracket 1 10 4.5~5.5
Upper bolt for rear cushion 1 10 3.5~4.5
Lower bolt for rear cushion 1 8 2.4~3.0
Rear wheel nut 1 16 10.0~12.0

1. General Information

1-9

Cables and Harness Routing

Note the following when routing cables
and wire harnesses:

•

A loose wire, cable or harness may cause
safety hazard. After clamping, check each
wire to make sure it is secured.

•

Do not squeeze wires against the weld or its
clamp.

•

Secure wires and wire harnesses to the frame
with respective wire bands at the designated
locations. Tighten the bands so that only the
insulated surfaces contact the wires or wire
harnesses.

•

Route harnesses so that they neither pull too
tight nor have excessive slack.

•

Protect wires or wire harnesses with electrical
tape or tube if they contact a sharp edge or
corner.

•

Route wire harnesses to avoid sharp edges or
corners.

•

Avoid the projected ends of bolts and screws.

•

Keep wire harnesses far away from the
exhaust pipes and other hot parts.

•

Be sure grommets are seated in their groves
properly.

•

After clamping, check each harness to be
certain that it is not interfered with any moving
or sliding parts.

•

After routing, check that the wire harnesses
are not twisted or kink.

•

Wire harnesses routed along the handlebar
should not be pulled too tight or have
excessive slack, be rubbed against or interfere
with adjacent or surrounding parts in all
steering positions.

•

Thoroughly clean the surface where tape is to
be applied.

•

Wrap electrical tape around the damaged parts
or replace them.

O

：Correct

X

：Wrong

1. General Information

1-10

High/low beam switch

Horn switch

Rear brake lamp

Winker switch

Speedometer

Headlight

Starter switch

Throttle cable

Headlight

Rear brake cable

Speedometer

Throttle cable

Main switch

Regulator

Resistor

Horn

Front brake
hose

Speedometer cable

Front brake cable

Winker relay

Front brake
lamp switch

1. General Information

1-11

Throttle cable

Rear brake cable

Fuel unit cord

Fuel filter

Speedometer cable

Rear brake cable

Front brake

Throttle cable

Fuel unit

Winker relay

Front brake hose

Rear brake cable

Speedometer cable

Throttle cable

Front brake hose

Fuel pump

1. General Information

1-12

Fuel filter

Battery

C.D.I. UNIT

Fuse

Purge control valve

Oil control cable

Fuel hose

Fuel pump

Vacuum hose

Oil hose

Rear brake cable

Carburetor

Oil lever switch

1. General Information

1-13

Troubleshooting

A. Engine hard to start or can not be started

Check and adjustment

Fault condition Probable causes

Loosen carburetor drain bolt to
check if there is gasoline
inside the carburetor

Fuel supplied tom

carburetor sufficient

No fuel is supplied to

carburetor

Remove spark plug, install it
into spark plug cap, and
perform a spark test against
engine ground.

Perform cylinder compression
pressure test.

Check if sparks Week sparks or no

spark at all

Cylinder compression

pressure normal

Low compression

pressure or no pressure

Re-start by following the
starting procedures

No ignition

There are some signs of

ignition, but engine can

not be started
Remove the spark plug again
and check it.

Remove carburetor after 30
minutes and connect a hose
onto fuel supplement circuit.
Then blow the hose with air.

Dry spark plug Wet spark plug

Blowing in normal Blowing clogged

1. No fuel in fuel tank

2. Check if the pipes, fuel tank to
carburetor and intake vacuum, are
clogged.

3. Float valve clogged

4. Lines in fuel tank evaporation system
clogged

5. Malfunction of fuel pump

6. Loosen or damaged fuel pump vacuum
hose

7. Fuel filter clogged

1. Malfunction of spark plug

2. Spark plug foul

3. Malfunction of CDI set

4. Malfunction of AC generator

5. Ignition coil is in open or short circuit

6. Ignition coil leads open or short circuit

7. Malfunction of main switch

1. Piston ring seized

2. Malfunction of cylinder valves

3. Worn cylinder and piston ring

4. Cylinder gasket leak

5. Sand hole in compression parts

6. Crankcase leakage for pre-compression

1. Malfunction of throttle valve operation

2. Air sucked into intake manifold

3. Incorrect ignition timing

1. Fuel level in carburetor too high

2. Malfunction of throttle valve operation

3. Throttle valve opening too wide

1. Malfunction of auto-starter

1. General Information

1-14

1. General Information

1-15

B. Engine run sluggish (Speed does not pick up, lack of power)

Try gradual acceleration and
check engine speed

Engine speed can be

increased.

Engine speed can not

be increased.

Check ignition timing (Using
ignition lamp)

Check cylinder compression
pressure (using compression
pressure gauge)

Ignition timing correct Incorrect ignition timing

Compression pressure

correct

No compression

pressure

Check if carburetor is clogged

Normal Clogged

Remove spark plug

Check if engine over heat

No foul or discoloration

Fouled and discoloration

No knock Knock

1. Air cleaner clogged

2. Poor fuel supply

3. Lines in fuel tank evaporation system
clogged

4. Exhaust pipe clogged

1. Malfunction of CDI

2. Malfunction of AC generator

1. Cylinder & piston ring worn out

2. Cylinder gasket leaked

3. Sand hole in compression parts

4. Valve deterioration

5. Crankcase leakage for pre-compression

1. Remove dirt

1. Remove dirt

2. Incorrect spark plug heat range

1. Piston and cylinder worn out

2. Lean mixture

3. Poor fuel quality

4. Too much carbon deposited in
combustion chamber

5. Ignition timing too advanced

Normal

Engine

overheat

Continually drive in
acceleration or high speed

1. Too much carbon deposited in
combustion chamber

2. Lean mixture

3. Poor fuel quality

4. Lean mixture

Check and adjustment Fault condition Probable causes

1. General Information

1-16

1. General Information

1-17

C. Engine runs sluggish (especially in low speed and idling)

D. Engine runs sluggish (High speed)

Check ignition timing (using
ignition lamp)

Good spark Poor

No air sucked Air sucked

Good Poor

Normal Abnormal

Air sucked through carburetor
gasket

Adjust the air screw of
carburetor

Remove spark plug, install
spark plug into spark plug cap
and perform spark test against
engine ground

Check for fuel supplying
system in automatic fuel cup

Check if carburetor clogged

Good

Poor

Check ignition timing

Normal

Abnormal

Normal Clogged

1. Incorrect ignition timing (malfunction of
CDI or AC generator)

1. Rich mixture (loosen the screw)

2. Lean mixture (tighten the screw)

1. Poor heat insulation gasket

2. Carburetor lock loose

3. Poor intake gasket

4. Poor carburetor O-ring

1. Spark plug fouled

2. Malfunction of CDI

3. Malfunction of AC generator

4. Malfunction of ignition coil

5. Open or short circuit in spark plug leads

6. Malfunction of main switch

1. Insufficient fuel in fuel tank

2. Fuel filter clogged

3. Restricted fuel tank vent

1. Malfunction of CDI

2. Malfunction of AC generator

1. Cleaning

Check and adjustment

Fault condition Probable causes

Check and adjustment

Fault condition Probable causes

1. General Information

1-18

1. General Information

1-19

E. CLUTCH, DRIVING AND DRIVING PULLEY

1. Clutch ling spring broken

2. Clutch outer cover stuck with clutch balance
weights

3. Connection parts in clutch and shaft worn out or
burned

Engine can be started but
motorcycle can not be driving

FAULT CONDITION

PROBABLE CAUSES

1. Driving belt worn out or deformation

2. Driving disk damaged

3. Driving pulley spring broken

4. Clutch ling broken

5. Driving slide-shaft gear groove broken

6. Transmission gear damage

7. Transmission gear worn out or burned

Engine running and misfire as

motorcycle initial forward moving

or jumping sudden (rear wheel
rotating as engine in running)

Poor initial driving (Poor
climbing performance)

1. Driving belt worn out or deformation

2. Balance weight roller worn out

3. Driving sliding gear shaft worn out

4. Driving disk spring deformation

5. Driving sliding gear shaft worn out

6. Greased in driving belt and sliding gear.

1. General Information

1-20

Lubrication Points

Seat catch

Rear wheel bearing

Steering shaft bearing

Speedometer gear/
front wheel bearing

Side stand shaft

Main stand shaft

Throttle cable/
Front & rear brake lever pivot

1. General Information

1-21

Note:

2. Service Maintenance Information

2-1

General Information ······························2-1
Periodical Maintenance Schedule········2-2
Air Cleaner·············································2-3
Fuel Lines ··············································2-3
Fuel Filter···············································2-4
Engine Oil Line······································2-4
Oil Pump Control Cable························2-5
Battery····················································2-5
Tire··························································2-6
Rear Drum Brake Free Play··················2-6
Disc Brake System Hose ······················2-7
Steering System····································2-9
Suspension············································2-9

Transmission Oil··································· 2-10
Spark Plug·············································2-10
Control Cable Lubrication···················· 2-11
Driver Belt·············································· 2-11
Ignition Timing······································2-11
Throttle Valve Operation······················ 2-11
Carburetor Idle Speed Adjustment······ 2-12
Carbon Removing For Exhaust Pipe &

Muffle····················································· 2-12
Cylinder Compression Pressure Test· 2-12
Headlight Adjustment··························· 2-13
Special Tool Manual····························· 2-14

General Information

Specification

Item Jet Sport X 50 series

Tire dimension Front: 120 / 70 – 12, Rear: 130 / 70 - 12
Tire pressure at cold Only rider

Front: 1.75kg/cm2, Rear: 2.0 kg/cm2

Rear brake lever free play

10~20 mm

Transmission oil

/ Recommendation

Type: HYPOID GEAR OIL
Oil: SAE #140 Quantity: 0.12 L,

Replacement

: 0.11L

Spark plug

/ Recommendation

Type: NGK BR8HAS / Plug gap: 0.6-0.7mm

Driving belt width

Standard 18.0mm
Allowable limit: replace it if below 16.5mm

Ignition timing F mark

17°, BTDC/1500 rpm

Acceleration operation

2~6 mm

Idle speed

2000±100 rpm

Cylinder compression pressure

7

±

1

kgf/cm²

2

Home page

Contents

2. Service Maintenance Information

2-2

Periodical Maintenance Schedule

Maintenance
kilometer

300KM

Every

1000KM

Every

3000KM

Every

6000KM

Every

12000KM

Check item

Maintenance
interval

New 1 month 3 month 6 month

1 year

Reference

☆

1. Air cleaner

I C R

☆

2. Fuel filter

C

☆

3. Engine oil filter cleaning

C C

☆

4. Oil pump linkage operation
check

I I

5. Tire pressure

I I

6. Battery inspection

I I

7. Brake & free play check

I I

8. Steering handle check

I I

9. Cushion operation check

I I

10. Every screw tightening check

I I

11. Gear oil check for leaking

I I

☆

12. Spark plug check or change

I R

☆

13. Gear oil change

R Replacement for every 5000km

14. Frame lubrication

L

15. Exhaust pipe

I I

☆

16. Carburetor

I I

17. Driving belt check

I

☆

18. Ignition timing

I I

☆

19. Emission check in Idling

I I

☆

20. Idle speed check

I I

21. Fuel lines

I I

☆

22. Throttle operation

I I

☆

23. Engine bolt tightening

I I

☆

24. Engine screw torque

I

☆

25. Carbon cleaning for cylinder
head, cylinder, and piston
head, and exhaust system.

I

Have your scooter checked, adjusted periodically by your SYM Authorized Dealer to maintain the scooter at the
optimum condition.

Code: I ~ Inspection, cleaning, and adjustment R ~ Replacement

C ~ Cleaning (replaced if necessary) L ~ Lubrication

The above maintenance schedule is established by taking the monthly 1000 kilometers as a reference which ever
comes first.

Remarks:

1. Clean or replace the air cleaner element more often for pro-long engine life-span when the scooter is
operated on dusty roads or in the Heavily- polluted environment.

2. Maintenance should be performed more often if the scooter is frequently operated in high speed and
after the scooter has accumulated a higher mileage.

This chapter Contents

2. Service Maintenance Information

2-3

Air Cleaner



Remove the mounting screw from the air
cleaner cover



Remove the air cleaner cover

Remove the air cleaner element
Clean the element with non-flammable or
high-flash point solvent and then squeeze it for
dry.

Caution

Never use gasoline or acid organized solvent to
clean the element.

Soap the element into cleaning engine oil and
then squeeze it out. Install the element onto the
element seat and then install the air cleaner
cover.



Limit to use SAE 20 JASO FC class engine oil;
otherwise, SYM is no responsible for the
warranty.



Recommended engine oil: MAX-2 serial oils.

Fuel Lines

Remove the luggage box.
Check fuel lines and replace damaged lines if
found.
Install the luggage box.

Air cleaner element

Squeeze out remaining oil

Soap

Clean

Squeeze oil out

Fuel pump

Carburetor

Fuel line

5 screws

This chapter Contents

2. Service Maintenance Information

2-4

Fuel Filter

Remove the luggage box.
Remove the fuel line from the fuel filter.
Replace the fuel filter with new one.
Install the fuel filter. The arrow indicates the fuel
flowing direction.
Check the fuel line for leaking.

Engine Oil Line

Remove the body cover.
Check the engine oil line and replace damaged
parts.
Remove the filling pipe from the oil pump, and
drain oil into a cleaning container.
Loosen the clamp under the engine oil tank, and
then remove the oil pipe.
Bleed the air inside the oil pump and oil pipe if air
found.
Install the body cover.

Fuel filter

Oil filling pipe

Engine oil pipe

Oil pump

This chapter Contents

2. Service Maintenance Information

2-5

Oil Pump Control Cable

Caution

To adjust the oil pump control cable after
adjusted the throttle grip play.

Remove the luggage box.
Wide open the throttle valve, and check if the
calibration point aligns on the oil pump lever with
the mark of pump body.

Loosen the adjustment nut of the oil pump control
cable.
Turn the adjustment nut and align with the point,
then tighten the mounting nut.

Battery

Open the seat.
Loosen two screws of battery cover and then
remove the cover.
Check if the battery terminals are loosened.
Remove the battery if its terminals are corroded
obviously.

Battery Removal

1. Remove the Negative (-) battery cable at first.

2. Then, remove the Positive (+) battery cable.

3. Remove the battery.
Clean the rust with steel brush.
Install the battery in reverse order of removal, and
apply with grease onto two terminals.

Caution

The electrolyte is contained sulfuric acid so be
careful not to let it touch to eyes, skin, or
clothes. If touched by accident, flush them
with clean water immediately. However, if the
electrolyte sprays to eyes, medical care should
be done quickly.

Mounting nut

Adjustment nut

This chapter Contents

2. Service Maintenance Information

2-6

Tire

Caution

Tire pressure should be checked when cold.

Check tire for cracks, damage, nail, or other
object stuck in tread.
Recommended tire and tire pressure

Tire size

Front:
120 / 90 - 10

Rear:

130 / 90 - 10
Tire pressure
(cold) kg/cm2

1.75 2.0

Check if the tire tread and wall rubber for crack or
damage, and replace if necessary.
Check if foreign materials such as nail, metal
pieces, and stones stuck on tire.
The thread depth can be checked by visual
inspection or by a depth gauge.



If the tread bend too much, replace the tire.



If tire wear exceeds limitation, replace the tire,
and check it for un-even wear.

Caution

Wear indicator “△ ” is distributed on average
along the wall rubber for check.

Rear Drum Brake Free Play

Measure the free play of the rear brake lever at
the end of the lever.
Free play: 10-20 mm (3/8-3/4 in)

Adjust the free play by turning the front brake
adjustment nut if necessary.

Brake Confirmation

Caution

After brake adjustment, it has to check the
brake operation to make sure the front and rear
wheel can be braked.

Wear indicator

△

△△

△ Mark

10~20mm
(3/8~3/4in)

Adjustment nut

Increasing
free play

Decreasing free
play

This chapter Contents

2. Service Maintenance Information

2-7

Disc Brake System Hose

Make sure that the brake hose is corrosion or
damage, and also check the system for leaking.

Brake Fluid:

Check brake fluid level in the brake fluid reservoir.
If the level is lower than the LOWER limit, add
brake fluid DOT-3 to UPPER limit. Also check
brake system for leaking if low brake level found.

Caution



In order to maintain brake fluid in the
reservoir in horizontal position, do not
remove the cap until handle bar stop.



Do not operate the brake lever after the cap
had been removed. Otherwise, the brake
fluid will spread out if operated the lever.



Do not mix non-compatible brake fluid
together.

Brake Lining Wear: (Rear Drum Brake
Type)

Replace the brake lining if the wear limit mark “△ ”
on the brake arm aligning with the indicator of

brake drum.
Brake lining replacements refer to chapter 12.

Brake pad Wear: (Disc Brake Type)

The arrow mark on brake pad is the wear
limitation.
Replace the brake pad if the wear limit mark
closed to the edge of brake disc.

Caution

In order to maintain brake power balance, the
brake lining must be replaced with one set.

Brake pad replacements refer to chapter 12.

This chapter Contents

Brake pad

Brake caliper

Brake disc

Wear limit mark

Arrow

Lower level

2. Service Maintenance Information

2-8

Loosen the guide pin bolts.
Remove the front wheel shaft bolt.
Take out the front wheel.

Remove brake caliper mounting bolt and then
remove the brake caliper.

Caution

Do not operate the brake lever after the clipper
removed to avoid clipping the brake lining.

Pry out the brake lining with a flat driver if lining is
clipped.

Remove brake lining bolt.
Take out the lining.

Tighten Torque:

Mounting bolt: 2.9-3.5kgf-m
Pin bolt: 1.5-2.0kgf-m
Pin bolt cap: 0.8-1.2kgf-m

The brake light switch is to light up brake light as
brake applied. Replace the switch if the light
does not light up in properly.

Caution

The brake light switch is un-adjustable.

This chapter Contents

Pin bolt

Brake lining

Lining guide bolts

Front brake

Caliper bolt

2. Service Maintenance Information

2-9

Steering System

Caution

The control cables cannot interfere with the
rotation of steering handle.

Lift the front wheel out of ground, and check if the
steering handle turning is smoothly.
If handle turning is uneven and bending, stuck, or
the handle can be operated in vertical direction,
then adjust the handle top bearing by adjusting
the steering nut.

Suspension

Warning

Do not ride the scooter with poor suspension.
Looseness, wear or damage suspension
system will make poor stability and drive-ability.

Front Shock Absorber

Press down the front shock absorber for several
times to check it operation.
Check if the shock absorber assembly is damage.
Replace it if damage found and can not be
repaired.
Tighten all nuts and bolts.

Rear Shock Absorber

Park the scooter with its main stand.
Shake the rear wheel side to side to check engine
suspension bushing for wear.
Replace the bushing if looseness found. Check
the shock absorber for damage.
Tighten all nuts and bolts.

Nuts, Bolts Tightness

Check if all bolts and nuts on the frame are
tightened to specified torque in accord with the
interval of Periodical Maintenance Schedule.
Check all split pins, snap rings, hose clamps, and
wire holders for security.

This chapter Contents

2. Service Maintenance Information

2-10

Transmission Oil

Leak

Check if the transmission is leak.

Check

Caution

Park the scooter on flat ground with its main
stand.

Remove the oil level check bolt, and check if the
oil level is placed on the hole of check bolt.

Replacement

Remove the oil level check bolt.

Remove the oil draining bolt, and then drain oil

out.
Install the oil draining bolt.

Tighten torque: 1.3kgf-m

Caution

Check if oil seal and washer is in good
condition.

Replacement Quantity: 0.09 L (90 cc)
Recommended oil: King Bramax HYPOID
GEAR OIL #140

Spark Plug

Recommended plug: NGK BR8HSA



Remove the luggage box.



Remove the spark plug cap.



Clean any dirt on the spark plug seat.



Remove the spark plug.



Visually inspect the spark plug electrodes for
wear.



The center electrode should have square
edges and side electrode should have a
constant thickness. Replace the spark plug if
there is apparent wear or if the insulator is
cracked and/or chipped. If the spark plug
deposits can be removed by sandpaper, the
spark plug can be reused.



Measure the spark plug gap with feeler gauge.

Spark plug gap: 0.6-0.7mm (0.024-0.028in)



Adjust the gap by careful bending the side
electrode.



Install the spark plug by screwing it with hands
after installed the spark plug washer so that
can prevent the plug from out of thread. Then,
tighten the spark plug with a spark plug wrench.



Install the spark plug cap.

This chapter Contents

Oil level check bolt

Draining bolt

Oil level check bolthole

0.6~0.7mm

Side electrode

Center electrode

2. Service Maintenance Information

2-11

Control Cable Lubrication

Remove the throttle control and the brake cables
periodically, and lubricate the moving parts of the
cables thoroughly.

Driver Belt



Remove left crankcase cover.



Check if the belt is crack or worn out. Replace
the belt if necessary.



Measure the driving belt width

Allowable limit: 16.5mm

Ignition Timing

Caution



C.D.I ignition timing cannot be adjusted. If
the ignition timing is incorrect, check the
C.D.I. device and the alternator and replace
damaged components.



Check ignition timing with standard
instrument.

Remove the right-side cooling fan cover.
Check ignition timing with the timing light.
When engine speed setting to 1800 rpm, and if
the mark aligns with “F” mark, then it means that
the ignition timing is correct.

Throttle Valve Operation

Check if each steering positions are operated in
smooth, and handle bar if its operation is smooth
as the throttle valve wide opening or fully closed.
Check throttle cable and replace it if deteriorated,
twisted or damaged.
Lubricate the cable if operation is not smooth
Measure throttle valve handle free play.

Free play：：：：2~6 mm (1/8~1/4 in)

Loosen the mounting nut, and turn the free play
adjustment nut of the throttle valve handle for
adjustment.
Replace the cable if it can not be adjusted.

This chapter Contents

Tooth face

Belt width

Ignition lamp

“F” mark

2. Service Maintenance Information

2-12

Carburetor Idle Speed Adjustment

Caution



Inspection & adjustment for idle speed have
to be performed after all parts in engine had
been adjusted in specification.



Idle speed check and adjustment have to be
done after engine is being warned up. It
around operates engine from stop to running
for 10 minutes.

Remove the body cover.
Park the scooter with main stand after warned up
engine. According to the required idling and air
screw to adjust to specified idle speed.

Idle speed: 2000±±±±100 rpm

Carbon Removing For Exhaust Pipe
& Muffle

Remove the body cover.
Remove the exhaust pipe & muffler.
Clean the carbon deposits on the muffler &
cylinder exhaust edge.

Cylinder Compression Pressure Test

Remove the left body cover, and warn up engine.
Stop the engine and remove the spark plug.
Insert the compression gauge and wide open the
throttle, and then rotate the engine by means of
the starting motor.

Compression pressure: 7.0±1 kg/cm

2

Probable causes for low compression pressure.



Damaged cylinder head gasket.



Worn piston ring



Worn cylinder

Probable causes for high compression pressure.



Carbon on the combustion chamber or cylinder
head

Adjust the idling after warn up engine for 10
minutes.

4. Connect tachometer.

5. Adjust the idle speed screw to let engine
speed in 2000±100 rpm.

6. Insert the sampling pipe of the CO/HC meter to
the test hole on the front end of exhaust pipe.
Adjust the idling emission value to standard
range. (CO: 1.8-2.6%)

7. Slightly accelerate the throttle valve and
release it. Repeat this operation for 1-2
times.

8. Read the engine idle speed and the emission
value after engine speed in stable. Repeat the
operation on step No. 2 – No. 4. until these
value within standard range.

This chapter Contents

Pilot screw

Idle speed adjustment screw

Compression pressure gauge

2. Service Maintenance Information

2-13

Headlight Adjustment

Turn the headlight- adjustment bolt for adjustment
its light beam.

Caution

Improper headlight beam adjustment will make
in coming driver dazzled or insufficient lighting
for safety distance.

This chapter Contents

Headlight adjustment bolt

Higher

Lower

2. Service Maintenance Information

2-14

Special Tool Manual

N

ame

R/L. Crankcase disassemble
tool

N

ame

R/L. Crank puller N

ame

R. Crank shaft puller

No. SYM-1120100-G5 No. SYM-1130000-L No. SYM-1130000-R

Nam

e

L. Crankshaft install bush N

ame

R. Crankshaft install bush N

ame

Extension bush

No. SYM-1130010 No. SYM-1130020 No.

SYM-1130031(long)
SYM-1130032(short)

(ø28mm)

(ø20mm)

Nam

e

Crankcase bush puller N

ame

Crankcase bush puller N

ame

ACG. Flywheel puller

No. SYM-1120310 No. SYM-1120320 No. SYM-3110A01

(25*37*6)

(20*32*6)

(27*42*7)

Nam

e

Oil seal driver N

ame

Oil seal driver N

ame

Oil seal driver

This chapter Contents

2. Service Maintenance Information

2-15

No. SYM-9121600 No. SYM-9120200 No. SYM-9125500

2. Service Maintenance Information

2-16

(6301)

(6203/6004UZ)

(6204)

N

ame

Bearing driver 6301 N

ame

Bearing driver Ø17mm N

ame

Bearing driver 6204

No. SYM-9610000 No. SYM-9620000 No. SYM-9110400

N

ame

Inner bearing puller N

ame

Inner bearing puller N

ame

Outer bearing puller

No. SYM-6204020 No. SYM-6204022 No. SYM-6204001

N

ame

Clutch nut wrench N

ame

Clutch spring compressor N

ame

Universal holder

No. SYM-9020200 No. SYM-2301000 No. SYM-2210100

N

ame

Multi-meter

No. SYM-HE07007-01

This chapter Contents

3. Lubrication System

3-1

Lubrication System Diagram················ 3-1
Precautions In Operation······················ 3-2
Lubricant················································ 3-2
Trouble Shooting ··································3-2

Oil Pump Removal·································3-3
Oil Pump Installation·····························3-3
Oil Pump/Oil Tube Air Bleeding············3-4
Oil Tank ··················································3-5

Lubrication System Diagram

Oil pump

Oil output tube

Oil tube

Oil lever switch

Oil tank

3

Home page

Contents

3. Lubrication System

3-2

Precautions in Operation

Be careful not let dirt enters into engine or oil hoses when removing or installing the oil pump.
If air is found in the oil tube (from oil tank to oil pump) or oil tube is removed, the oil pump should be
conducted air-bleeding operation.
It should bleed the oil output tube (from oil pump to carburetor) as hose removed.
The adjustments of oil pump control cable.

Lubricant

Appointed to apply SAE 20 JASO FC class oil. Otherwise, warranty shall not cover the damage.

Recommended oil: MAX-2 oil.
Oil tank capacity: 1.2 lit.

Trouble Shooting

Too much smoke, carbon in spark plug

1. Improperly oil pumps adjustment (too much oil).

2. Poor quality oil.

3. Applying with poor quality oil.

Over heat

1. Improperly oil pumps adjustment (insufficient oil).

2. Poor quality oil.

3. Applying with poor quality oil.

Piston seized

1. No oil in oil tank or clogged hose.

2. Improperly oil pumps adjustment (insufficient oil).

3. Air in oil hose.

4. Malfunction of oil pump.

Oil did not flow out the oil tank

1. Clogged breath hole on the oil tank cover.

This chapter Contents

3. Lubrication System

3-3

Oil Pump Removal

Caution

Before removing the oil pump, clean the oil
pump and crankcase.

Remove the luggage box and seat.
Loosen the mounting nut of the oil pump control
cable, and remove the control cable.
Remove the oil tube, and clip its end side to
prevent oil from flowing out.

Remove the oil output tube form intake manifold.
Remove the oil pump mounting bolt, and then
take out the oil pump.

Inspection

Inspect the following items on the removed oil
pump.
Check if O-ring is damaged or softening.
Check if crankcase interface is damaged.
Check if pump body is damaged.
Check if pump gear is damaged.
Check for oil leaking.

Caution

The oil pump cannot be disassembled.

Oil Pump Installation

Install the oil pump onto the crankcase.

Caution

Apply with some grease onto oil pump O-ring.
The connection between both oil pump and
crankcase has to be installed in position
security.

Tighten the oil pump mounting bolt security.
Install the oil tube.
Install in the reverse order of removal.

Caution

Inspection and adjustment following items as
installed.
The adjustment operation of control cable.
Air bleeding operation of oil pump.
Air bleeding operation of oil tube.
Check each section for leaking.

This chapter Contents

O

il tube

C

ontrol cable

Oil output tube

Adjustment nut

Mounting nut

1 bolt

O-ring

Pump gear

3. Lubrication System

3-4

Oil Pump/Oil Tube Air Bleeding

Caution

The oil tube system has to be conducted air
bleeding operation because air will clog or
restraint oil flowing so that causes serious
engine damage.

Caution

After disconnect the oil tube, air enters oil tube
due to oil leak out without added oil. There is
why the oil tube and oil pump have to conduct
air bleeding operation.

Oil Tube/Oil Pump

It has to add some oil into the oil tank.
Place a piece of dry cloth around the oil pump.
Disconnect the oil tube.
Fill out oil to oil pump connection section by
means of the oil pot so that the oil pump body is
full with oil.
Fill out oil to oil tube connection section so that
the oil tube is full with oil. Then, install the tube
onto oil pump.
Make sure whether air is in the oil tube or not
after installation.

Caution

After bleeding the oil tube and oil pump, the oil
tube has to be conducted air bleeding
operation too.

Oil Tube Air Bleeding

Remove the oil output tube and plug its input
connector. Bend the oil tube into “U “shape, and
fill out new oil into the output tube.
Connect the oil output tube to the oil pump
connection part.
Start engine, and run it in idling as the oil control
lever in wide open position. Make sure oil flows
out from the oil output tube.

Caution

Motorcycle’s exhaust gas includes with CO,
which causes human to coma or death so
perform this operation in well-ventilation place.
Run the engine in extreme low speed to avoid
to damaging the engine caused from clogged
oil tube.

This chapter Contents

Oil tube

Oil output tube

Recommended oil

Oil tube

Control cable

Oil output tube

3. Lubrication System

3-5

Oil Tank

Removal

Remove the luggage box and seat.
Remove the right / left side covers, right / left rear
side covers, center cover, rear carrier, body
covers, rear fender and rear inner fender. (Refer
to chapter 11)
Remove the battery and battery case (1 bolt).

Remove the oil input tube from oil pump, and then
drain oil to a clean container.

Remove the oil level switch wire coupler of the oil
indicator.

Remove the mounting bolt on the oil tank upper
side, and then remove the oil tank.

Installation

Install in the reverse order of removal.
The oil tubes air bleeding after installation.

This chapter Contents

Oil level switch coupler

1 blot

1 bolt

3. Lubrication System

3-6

Notes:

This chapter Contents

4. Fuel System

4-1

Maintenance Information ······················4-2
Troubleshooting ····································4-2
Throttle Valve·········································4-3
Carburetor Remove ·······························4-4
Auto By-Starter······································4-4
Float/Float Valve/Jet······························4-6

Flaot Level Inspection ·························· 4-7
Carburetor Installation·························· 4-7
Reed Valve············································· 4-7
Fuel Pump·············································· 4-8
Air Cleaner············································· 4-9

4

Fuel tank

Fuel unit

Fuel filter

Vacuum tube

Fuel pump

Carburetor

Fuel output tube

Throttle valve cable

Fuel cap

Home page Contents

Fuel inlet tube

4. Fuel System

4-2

Maintenance Information

Precautions in Operations

Warning

Gasoline is a highly flammable material and may explosive under circumstance. Thus, always work in
a well-ventilated place and strictly prohibit flame when working with gasoline.

 Care must be taken when dealing with gasoline, and always work in a well-ventilated place and

strictly prohibit flame.

 When disassembling fuel system parts, pay attention to O-ring position, replace with new one as

re-assembly

 It has to conduct air bleeding operation as removed the oil tube.
 Idle speed adjustment.

Specification

Item Jet Sport X 50
Ventura diameter 15 mm
Fuel level

8.8±1.0mm
Air screw opener 1 3/8
Idle speed

2000±100 rpm

Throttle handle free play 2~6 mm

Troubleshooting

Engine cannot be started

1. No fuel in fuel tank

2. Fuel can not reach to carburetor

3. Too much fuel in cylinder

4. Clogged air cleaner

Stall after started

5. Incorrect idle speed adjustment

6. No spark on the spark plug

7. Low compression pressure

8. Rich mixture

9. Lean mixture

10. Clogged air cleaner

11. Inlet pipe leaking

12. Polluted fuel

Lean Mixture

1. Clogged carburetor jet

2. Clogged hose from carburetor to canister

3. Bend, squeezed or clogged fuel lines

4. Clogged fuel filter

5. Malfunction of float valve

6. Low fuel level in float chamber

7. Clogged vent pipe

8. Malfunction of fuel pump

Rich Mixture

13. Malfunction of float valve

14. Low fuel level in float chamber

15. Clogged carburetor air injector

This chapter Contents

4. Fuel System

4-3

Throttle Valve

Removal

Remove the body cover.
Remove the carburetor upper part, throttle valve
spring and sealed cap.
Remove the throttle valve cable from the throttle
valve.
Remove needle clamp and fuel needle.

Inspection

Installation

Place the fuel needle onto the throttle valve and clip it with needle clamp.
Install the sealed cap, carburetor upper part, and throttle valve spring.
Connect the throttle valve cable to the throttle valve.
Install the throttle valve into the carburetor body.

Caution

Align the groove inside the throttle valve with the throttle stopper screw of the carburetor body.

Tighten the carburetor upper part.
Adjust the free play of throttle valve cable.

Needle clamp

Throttle valve spring

Fuel needle

Throttle valve cable

Sealed cap

Carburetor upper part

Washer

Throttle valve

Fuel needle clip

Carburetor upper part

This chapter Contents

4. Fuel System

4-4

Carburetor Remove

Remove the rear side cover.

Disconnect the auto by-starter coupler.

Loosen draining screw and then drain out fuel
inside the carburetor.
Loosen carburetor upper part and remove
carburetor upper part.
Remove fuel and oil hoses from carburetor.
Remove carburetor mounting bolt and carburetor.

Auto By-Starter

Inspection

Connect resistor meter to the terminals of auto
by-starter, and then measure its resistance.
If the resistance value exceeds specification too
much, it means that the PTC in the auto by-starter
is malfunction. Then, replace the auto by-starter.

Resistance value: Max. 10Ω (at cold engine)

Caution

If the resistance value exceeds the standard a
little bit, the auto by-starter may still in normal.
However, it is necessary to check other relative
components for damage.

Auto by-starter coupler

Carburetor
upper part

Connection hose clamp

Auto by-starter

2 bolts

Fuel hose

Draining screw

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4. Fuel System

4-5

Remove carburetor, and allow it to cool off for 30
minutes.
Connect fuel rich circuit with a hose and pump
compressed air to the hose.
Air should flow into fuel rich circuit.
Replace the auto by-starter if the circuit clogged.

Connect battery to starter’s connectors and wait
for several minutes.
Pump compressed air into the fuel rich circuit.
Air should not flow into the circuit.
If air flow through the circuit; then replace the
auto-by starter.

Check resistor to make sure that the auto
by-starter is in normal. Engine is running.
If the resistor is in open-circuit, then current will
not flow into the PTC. Thus, the auto by-starter
is not operated.
However, if the resistor is in short-circuit; current
higher than specification will flow into the PTC.
Then, it will cause the fuel rich circuit close rapidly,
and difficult to start the scooter.

Resistance value: 10.2Ω

Auto By-Starter Removal/Installation

Remove the cover of the auto by-starter.
Remove screw and mounting plate.
Remove the auto by-starter from carburetor.
Install in the reverse order of removal procedures.

Battery

Auto by-starter

Alternator

Resistor

Mounting
plate

2 screws

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4. Fuel System

4-6

Float/Float Valve/Jet

Removal

Remove the float from carburetor body.
Remove the float pin and then remove float and
float valve.
Check the valve seat for worn out or damage.
Check float for bend and if fuel inside the float.
Before removing both the throttle valve stopper
and air screws, record their original turns for close
to their original set up position as installation.

Caution

Do not tighten the screw forcedly to avoid to
damaging the valve seat.

Remove main jet, needle jet seat and idle jet and
clean them and each component with
compressed air.

Installation

Install the idle jet, the needle jet seat and main jet.
Then install the throttle valve stopper and air
screws to their original position according to the
marks as removal. Adjust the screws if replace
with new ones.

Air screw

Throttle valve
stopper screw

Needle jet

Needle jet seat

Main jet

Float pin

Float valve

Float

O-ring

Float cap

Screw

Draining screw

Idle jet

Air inlet for
fuel rich
circuit

Float cap

Air inlet for idle speed

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4. Fuel System

4-7

Float Level Inspection

Measures float fuel level to have the upper end of
float just contact with the float.

Float fuel level: 8.8 mm

Carefully bend the float arm for adjustment.
Check the float operation and the install it.

Carburetor Installation

Caution

Do not let foreign materials into the carburetor.

Install the carburetor and insulator onto intake
pipe with bolts.
Install fuel and vent pipes onto carburetor.
Install the carburetor upper part.
Tighten the connection hose.
Tighten the draining screw.
Connect the automatic by-starter connector.
Install air cleaner cap.
Conduct following operations

 Adjustment of throttle valve cable.
 Adjustment of oil pump.
 Adjustment of idle speed.

Reed Valve

Removal

Remove the luggage box.
Remove the carburetor.
Remove carburetor insulator.
Remove inlet pipe.
Remove the reed valve.

Reed valve

Inlet pipe

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Carburetor
upper part

Connection hose clamp

2 bolts

Fuel hose

Draining screw

4. Fuel System

4-8

Inspection

Check the reed valve for damage and its reed
strength.
Check the reed valve seat for crack, damage and
the clearance between the seat and the valve.
Replace reed valve if necessary.

Caution

Do not bend the reed valve stopper. Otherwise,
it will cause its strength insufficient and rough
engine running. If the reed valve or its seat is
damaged, replace with a set.

Installation

Install in the reverse order of removal procedures.
Check for leaking after installed.

Fuel Pump

Inspection

Remove the rear side cover.
Warm up the engine and adjust idle speed.
Remove fuel hose from carburetor and then wait
for 5 minutes.
Measure the output of fuel pump. Its output time
is 10 seconds.

Output quantity: Min. 20 c.c.

If the output quantity is lower than 20c.c., check
fuel hose, vacuum hose and fuel filter.

Removal/Installation

Remove floor plate.
Remove fuel inlet, outlet and vacuum hoses.
Remove 2 bolts and fuel pump.
Install the fuel pump in the reverse order of
removal procedures.

Carburetor

Fuel inlet
hose

Fuel outlet
hose

2 bolts

Vacuum
hose

Fuel hose

Reed valve stopper

Reed valve

Reed valve seat

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4. Fuel System

4-9

Air Cleaner

Removal/Installation

Remove air cleaner and rear inner fender
mounting screw.

Loosen connection hose clamp.
Remove 2 bolts and then remove the air cleaner.

Install in the reverse order of removal procedures.

1 screw

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2 bolts

Hose clamp

4. Fuel System

4-10

Notes:

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5. Engine Removal

5-1

Maintenance Information······················ 5-2
Engine removal······································ 5-3

Engine installation ······························· 5-6

5

2.4~3.0kgf-m

2.4~3.0kgf-m

5.5~6.5kgf-m

5.5~6.5kgf-m

5.5~6.5kgf-m

4.5~5.5kgf-m

Home page Contents

5. Engine Removal

5-2

Maintenance Information

There are parts that require removal of engine for maintenance.

●

Crankcase

●

Crankshaft

Related bolts tightening torque for removal of engine:

Engine hanger bolt 5.5~6.5kgf-m
Engine hanger bracket bolt 4.5~5.5kgf-m
Rear cushion upper mounting bolts 3.5~4.5kgf-m
Rear cushion lower mounting bolts 2.4~3.0kgf-m
Exhaust pipe connection nut 1.0~1.4kgf-m
Muffle mounting bolt 3.0~3.5kgf-m

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5. Engine Removal

5-3

Engine removal

Remove body cover.
Remove the spark plug cap from the spark plug.
Remove the fuel output and the vacuum tubes
from fuel pump.

Remove the oil control cable from oil pump.
Remove the oil tube from oil pump and then clip
the tube.

Remove the wire couplers of auto by starter and
ACG.

Remove the upper parts of the carburetor from its
upper side.
Remove the carburetor heater electric wire.

Vacuum tube

Fuel output tube

Wire couplers

Spark plug

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Carburetor
upper parts

Heater wire

O

il tube

C

ontrol cable

5. Engine Removal

5-4

Drum type rear brake

Remove rear brake cable from engine rear-lower
side.
Remove brake cable from cable clamp.

Disc type rear brake

Remove rear brake caliper (2 bolts) from engine
rear-upper side.
Remove brake hose from hose clamp.

Remove air cleaner and rear inner fender
mounting screw.

Loosen connection hose clamp.
Remove 2 bolts and then remove the air cleaner.

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1 screw

2 bolts

Hose clamp

R

ear brake

cable

Caliper

5. Engine Removal

5-5

Remove two exhaust pipe connection nuts.
Remove two bolts beside fan cover and exhaust
pipe.

Support the engine and then remove cushion
lower mounting bolt.

Remove engine mounting nut and bolt. (Each
side 1 bolt and 1 nut)
Remove the engine.

Engine mounting nut

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Rear cushion lower
mounting bolt

Engine mounting bolt

3 bolts

Connection nut

5. Engine Removal

5-6

Engine Hanger Bracket

Removal

Remove the frame side right and left side bolts of
engine hanger bracket. (1 bolt on each side)

Disassembly

Remove the engine hanger bracket nut and bolt.
Disassembly engine hanger bracket A and engine
hanger bracket B.
Check if the engine hanger rubber bushes,
hanger bushes and collar for damage. If so,
replace with new ones.

Assembly

Install hanger bushes and collar into engine
hanger bracket B.
Install engine hanger bracket A and engine
hanger bracket B and tighten the bolts and nuts
of engine hanger bracket.

Torque Value: 4.5~5.5kgf-m

Engine installation

Install in the reverse order of removal procedures.
Tighten the engine mounting bolts and rear
cushion upper/lower bolts.

Torque value:

Engine hanger bolt 5.5~6.5kgf-m
Rear cushion upper mounting bolts 3.5~4.5kgf-m
Rear cushion lower mounting bolts 2.4~3.0kgf-m
Exhaust pipe connection nut 1.0~1.4kgf-m
Muffle mounting bolt 3.0~3.5kgf-m

Perform the following inspection and adjustment
after installation.

●

Check if control cable is correct.

●

Check if throttle valve cable is correct.

●

Check if oil pump control cable is correct.

●

Oil input and output of the oil pump.

●

Adjust rear brake.

Engine mounting nut

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2 bolts

Engine mounting bolt

Engine hanger bracket A

Engine hanger bracket B

Bush

C

ollar

Rubber bush

Rubber bush

Bush

6. Cylinder Head/Cylinder/Piston

6-1

Maintenance Information······················6-2
Troubleshooting····································6-2

Cylinder Head·········································6-3
Cylinder/Piston·······································6-5

6

Home page

Contents

1.6~2.0kgf-m

1.1~1.7kgf-m

6. Cylinder Head/Cylinder/Piston

6-2

Maintenance Information

Precautions in Operation

 The inspection and maintenance of the cylinder head, cylinder and piston can be carried as engine

mounted on the body.

 It should clean the engine to prevent dirt from entering into cylinder and crankcase before removal.
 Remove all washes from the interfaces of cylinder head, cylinder and crankcase.
 Be careful do not damage cylinder head, cylinder and piston when removing.
 Inspect the removed & cleaned parts thoroughly, and apply with oil onto the rotation surfaces before

installation.

Specification

Jet Sport X 50 series

Item

Standard value (mm) Limit (mm)

Cylinder head Deformation - 0.100

Piston OD 39.030~39.045 38.935
Clearance between cylinder and piston 0.040~0.050 0.100
Piston pin hole 12.002~12.008 12.030
Piston pin OD 11.994~12.000 11.970
Clearance between piston and piston pin 0.002~0.014 0.030
Piston ring end gap 0.100~0.250 0.400

Piston

ID of connecting rod small end 17.05~17.015 17.025
ID 39.000~39.015 39.050

Cylinder

Deformation - 0.100

ID: inner diameter OD: outer diameter

Tighten torque value

Cylinder head 1.6~2.0kgf-m
Spark plug 1.1~1.7kgf-m
Exhaust pipe connection nut 1.0~1.4kgf-m
Exhaust muffler mounting bolt 3.0~3.6kgf-m

Troubleshooting

Compression Pressure Too Low/Difficult
To Start/Rough Idling

1. Cylinder head gasket leaking

2. Spark plug not tighten enough

3. Worn, seized or crack piston ring

4. Damaged, worn cylinder or piston

5. Poor reed

Compression Pressure Too
High/Overheat/Knock

1. Too much carbon deposit built up in
combustion chamber

Piston Noise

1. Cylinder and piston worn out

2. Piston pin or piston pin hole worn out

3. Connecting rod small end bearing worn out

Piston Ring Noise

1. Worn, seized or crack piston ring

2. Cylinder worn out or damaged

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6. Cylinder Head/Cylinder/Piston

6-3

Cylinder Head

Cylinder Head Removal

Removal luggage box, body covers and center
cover.
Remove fuel pump tubes.

Remove spark plug cap.
Remove fuel pump bracket (2 nuts).

Remove vacuum tube and oil pump control cable
from engine shield.

Remove fan cover (3 bolts).
Remove engine shield mounting bolt (1 bolt).

3 bolts

Engine shield

1 bolt

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2 nuts

Vacuum tube

Fuel output tube

Fuel inlet tube

Plug cap

6. Cylinder Head/Cylinder/Piston

6-4

Remove engine shield.

Cylinder Head Removal

Remove spark plug.
Remove the 4 cylinder head bolts and then
remove the cylinder head.

Caution

Loosen the cylinder head bolts with diagonal
direction to avoid to damaging it.

Cleaning Carbon in Combustion Chamber

Clean carbon deposit in which built up in
combustion chamber with shown chisel.

Caution

Do not scratch to the interfaces of combustion
chamber and cylinder.

Cylinder Head Inspection

Use a straight edge and a feeler gauge to
measure the cylinder head for warp.

Service limit: 0.10 mm

Cylinder Head Installation

Replace the cylinder head gasket with new one,
and place the cylinder head onto cylinder.
Tighten the 4 bolts with diagonal direction and by
2-3 sequences.

Tighten torque: 1.6~2.0kgf-m

Install spark plug

Tighten torque: 1.1~1.7kgf-m

4 bolts

Chisel

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6. Cylinder Head/Cylinder/Piston

6-5

Cylinder/Piston

Remove spark plug cap.
Remove fan cover.
Remove engine shield.
Remove two connection nuts of the exhaust pipe.
Remove exhaust muffle mounting bolt, and then
remove the exhaust muffler.

Cylinder Removal

Remove cylinder head.
Be careful to pull the cylinder up and prevent
piston from damage.

Caution

Do not have pry out operation between cylinder
and crankcase. Or let radiation fan be
knocked seriously.

Piston Removal

Place a clean rag onto crankshaft to cover the
piston.
Remove piston pin clip (one piece) and then push
piston pin out the piston.

Caution

 Do not damage or scratch the piston.
 Do not apply with lateral force to connecting

rod.

 Do not let piston pin snap ring falling into

crankcase.

Piston Ring Removal

Caution

Pry out the opening end of each piston ring and
then remove the ring from piston.

Piston pin clip

Piston pin

Piston

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3 bolts

Connection nut

6. Cylinder Head/Cylinder/Piston

6-6

Check if cylinder and piston are worn or damaged,
and then clean carbon deposit on exhaust
opening area as the diagram shown.

Caution

Do not scratch both the cylinder and the piston.

Use a straight edge and a feeler gauge to
measure the cylinder head for warp.

Service limit: 0.10 mm

In “X” and “Y” direction, measure the cylinder for
worn out as the three levels shown in the figure.
With the maximal value to decide cylinder wear
out condition.

Service limit: 39.050mm

Measure the OD of piston at the 7 mm from the
bottom of the piston.

Service limit: 38.935 mm

Calculate the clearance between piston and
cylinder.

Service limit: 0.100 mm

7mm

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6. Cylinder Head/Cylinder/Piston

6-7

Measure the piston pinhole ID of piston.

Service limit: 12.030mm

Measure the OD of piston pin.

Service limit: 11.970 mm

Piston Ring Inspection

Measure the end gap of each piston ring.

Service limit: 0.40 mm

Caution

With the piston, push each piston ring into
cylinder correctly.

Connecting Rod Inspection

Measure the ID of connecting rod small end.

Service limit: 17.025mm

Install bearing and piston pin onto connecting rod
small end, and then check its clearance.

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The ID of piston pinhole

The OD of piston pin

Clearance

6. Cylinder Head/Cylinder/Piston

6-8

Piston/Cylinder Installation

Install the expanding ring into the groove of 2nd
ring.
Align the ring end with the lock pin in the ring
groove.
Install the top ring and the 2nd ring onto the ring
groove respective.

Caution

The top ring and the 2nd ring cannot be
changeable each other.

Push the rings into ring groove and then check
rings’ mating condition.
If ring could not be push in the ring groove, it
means that ring groove is dirty or wrong ring
groove installation.

Caution

 All rings should be installed with the marks

facing up.

 All rings should be replaced at same time,

and it cannot be replaced one ring only.

 It should use same brand name piston ring in

an engine and cannot mix with other one.

Place a cleaning cloth onto the crankcase
opening to prevent the piston pin snap ring from
falling into the crankcase.
Apply with two-stroke engine oil onto needle
bearing and piston pin, and install needle bearing
into connecting rod small end.
Install piston, and place “EX” mark of the piston
toward to exhaust side, and then install the piston
pin onto piston and connecting rod.

Install new piston pin snap ring.
Clean all gaskets onto the interfaces of cylinder
and crankcase.
Place a new gasket onto the crankcase.
Make sure that the piston ring aligns with the lock
pin in piston ring groove.

Caution

Make sure that all rings in the piston ring
groove cannot be rotated around the lock pin to
avoid to damaging the rings, piston and
cylinder.

Piston pin snap ring

Piston pin

Piston

〝

〝〝

〝EX〞〞〞〞mark

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Top ring

2nd ring

Expanding ring

Piston ring mark

1T: top ring
2T: 2nd ring

Needle bearing

6. Cylinder Head/Cylinder/Piston

6-9

6. Cylinder Head/Cylinder/Piston

6-10

Lubricate cylinder and piston with two-stroke
engine oil.
Hold the piston and then install it into cylinder.

Caution

To avoid to damaging the piston and the
cylinder sliding surface.

Install the cylinder head.

Tighten torque: 1.6~2.0kgf-m

Replace the exhaust pipe washer with new one
and then install exhaust pipe.
Tighten exhaust pipe connection nut.

Tighten torque: 1.0~1.4kgf-m

Tighten exhaust pipe mounting bolt.

Tighten torque: 3.0~3.6kgf-m

Install the removed parts in the reverse order of
removal procedures.
Inspect following item after installation.
Test engine compression pressure.
Check for engine noise.

4 bolts

Lock pin

3 b

olts

Connection nut

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6. Cylinder Head/Cylinder/Piston

6-11

Note:

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7. A.C. Generator

7-1

Maintenance Information ············7-2
Generator Removal······················7-3

Generator Installation··················7-4

7

3.5~4.5kgf-m

Home page

Contents

7. A.C. Generator

7-2

Maintenance Information

Precautions in Operation



The maintenance service of A.C. generator can be carried out directly on the scooter.



Please refer to Chapter 15 for the relative A.C. generator inspection.

Torque value:

Flywheel 3.5~4.5kgf-m

Special Service Tools:

Flywheel puller

SYM-3110A01

Universal holder

SYM-2210100

Coil resistance value for the A.C. generator

Y/L Y P Earth

Y/L 50~200Ω

Y 0.2~0.8Ω
P 0.2~0.8Ω

Earth 50~200Ω

AC. generator

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7. A.C. Generator

7-3

Generator Removal

Remove the luggage box and rear side cover.
Remove 3 bolts and then take out cooling fan
cover.

Remove 4 bolts, and then take out the cooling
fan.

Hold flywheel with universal holder.
Support the flywheel and the remove the 10 mm
nut on the flywheel.

Special tool:
Universal holder

SYM-2210100

Remove the flywheel with flywheel puller.

Special tool:
Flywheel puller

SYM-3110A01

Universal holder

Flywheel puller

4 bolts

3 Bolts

10mm flanged nut

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7. A.C. Generator

7-4

Disconnect generator wire coupler and pulse coil
coupler.

Remove the pulse coil and generator coil bolts (4
bolts), and then take out the generator assembly.

Caution

Care to be taken for not damaging the
generator coil.

Generator Installation

Install the generator assembly.
Connect the generator coupler.

Caution

Connect the generator wire harness properly
and then clip the harness with clipper.

Install the woodruff key onto the crankshaft
groove.

Caution



Clean dirt and metal pieces inside the
flywheel.



Make sure that there is no foreign material
inside the flywheel.

Install the flywheel.
Tighten the flywheel 10 mm nut.

Torque value: 3.5~4.5kgf-m

Install the removed parts in reverse order of
removal procedures.
Start engine and check its ignition timing.

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Pulse coil coupler

Generator coupler

4 bolts

10mm flanged nut

Universal holder

10mm flanged nut

8. "V" Type Belt Drive System/Kick-Starter

8-1

Maintenance Information·····················8-3
Trouble Shooting ·································8-3
Left Crankcase Cover ··························8-4
Reassembly Of Kick Starter ················8-5
Installation Of The Left Crankcase Cover

·······························································8-5

Drive Belt··············································8-6
Movable Driven Pulley·························8-7
Clutch/Driven Pulley····························8-11

8

5.5~6.5

kgf-m

3.5~4.5

kgf-m

5.0~6.0

kgf-m

Home page

Contents

8. "V" Type Belt Drive System/Kick-Starter

8-2

8. "V" Type Belt Drive System/Kick-Starter

8-3

Maintenance Information

Precautions In Operation

The surfaces of drive belt and driven pulley must be free of grease.

Specification

Item Standard value (mm) Limit (mm)

Drive belt width

18.0 16.5

ID of movable drive face

20.035~20.085 20.120

OD of movable drive face boss

23.964~23.985 23.918

OD of weight roller

15.92~16.08 15.40

ID of clutch outer

107.0~107.2 107.5

Thickness of clutch weight

4.0~4.1 2.0

Free length of driven pulley spring

87.9 82.5

OD of driven pulley

33.965~33.985 33.940

ID of movable driven face

33.000 34.060

ID: Inner Diameter
OD: Outer diameter

Torque Values:

Movable drive face 5.5~6.5kgf-m
Driven pulley plate 5.0~6.0kgf-m
Clutch outer 3.5~4.5kgf-m

Special Service Tools

Clutch spring compressor

SYM-2301000

Clutch nut wrench

SYM-9020200

Universal holder

SYM-2210100

Inner bearing puller SYM-6204020
Clutch bearing driver
Clutch seal driver

Trouble Shooting

Engine can be started but motorcycle
cannot be moved

1. Worn drive Belt

2. Worn ramp plate

3. Worn or damaged clutch weight

4. Broken driven pulley spring

Shudder or misfire when drive

1. Broken clutch weight

2. Worn clutch weight

Insufficient horsepower or poor
high-speed performance

1. Worn drive belt

2. Insufficient spring capacity of driven pulley

3. Worn weight roller

4. Driven pulley operation un-smoothly

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8. "V" Type Belt Drive System/Kick-Starter

8-4

Left Crankcase Cover

Left crankcase cover removal

Remove rear left body side cover.
Remove air cleaner (2 bolts).
Remove kick-start arm (1 bolt).
Remove left crankcase cover (9 bolts).

Disassembly of Kick Starter

Remove snap clip and thrust washer from left
crankcase cover.
Install kick-start arm, rotate the lever slightly and
then remove driven gear and washer.
Remove the kick-starter arm, kick starter spindle,
and return spring as well as socket.

Inspection of kick Starter

Check if starter spindle, driven gear for wear or damage.

Driven gear

Thrust washer

Friction spring

Return spring

Starter spindle

Snap ring

Kick start arm

Bolt

Thrust washer

Bush

Starter spindle

Driven gear

Return spring

9 bolts

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8. "V" Type Belt Drive System/Kick-Starter

8-5

Reassembly of Kick Starter

Install bush, return spring and starter spindle as
diagram shown.
Install thrust washer and snap clip onto starter
spindle.

Install kick-starter lever temporary.
Slightly rotate the lever and then align driven gear
with width-tooth on the starter spindle.
Install the friction spring of drive gear onto convex
part of the cover.

Installation of the Left Crankcase
Cover

Install the dowel pin and gasket.
Install the left crankcase cover.

Install kick-start arm.

Kick starter spindle

Convex part

Friction spring

Width-tooth

Return spring

Driven gear

Dowel pin

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8. "V" Type Belt Drive System/Kick-Starter

8-6

Drive Belt

Removal

Remove left crankcase cover.
Hold clutch outer with universal holder, and
remove nut and clutch outer.

Special tool:
Universal holder

SYM-2210100

Caution

 Using special tools for tightening or

loosening the nut.

 Fixed rear wheel or rear brake will damage

reduction gear system.

Push the drive belt into belt groove as diagram
shown so that the belt can be loosened, and then
remove the driven pulley.
Remove driven pulley/clutch. Do not remove
drive belt.
Remove the drive belt from the groove of driven
pulley.

Inspection

Check the drive belt for crack or wear. Replace
it if necessary.
Measure the width of drive belt as diagram
shown.

Service Limit: 16.5 mm

Replace the belt if exceeds the service limit.

Caution

 Using the genuine parts for replacement
 The surfaces of drive belt or pulley must be

free of grease.

 Clean up all grease or dirt before installation.

Installation

Caution

 Pull out driven pulley to avoid it closing.

Install drive belt onto driven pulley.

Nut

Clutch/drive belt

Universal holder

Belt tooth

Movable driven

pulley

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8. "V" Type Belt Drive System/Kick-Starter

8-7

Install the driven pulley that has installed the belt
onto drive shaft.

Hold the clutch outer, and then tighten nut to
specified torque value.

Special tool:
Universal holder

SYM-2210100

Torque value: 3.5~4.5kgf-m

Movable Drive Face

Removal

Remove fan cover and fan.
Remove left crankcase cover.
Hold generator flywheel with universal holder, and
then remove drive face nut.

Special tool:
Universal holder

SYM-2210100

Remove drive face.

Drive belt

Clutch outer

Drive shaft

Flywheel

Nut

Clutch/driven pulley

Drive face

Nut

Universal holder

Drive face

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8. "V" Type Belt Drive System/Kick-Starter

8-8

Removal

Remove movable drive face set and drive belt
from crankshaft.

Remove ramp plate.

Remove weight rollers from movable face.

Inspection

The weight roller is to press movable driven face
by means of centrifuge force. Thus, if weight
rollers are worn out or damage, the centrifuge
force will be affected.
Check if rollers are wearing out or damage.
Replace it if necessary.
Measure each roller’s outer diameter. Replace it if
exceed the service limit.

Service limit: 15.40 mm

Ramp plate

Movable drive face

Weight roller

Crankshaft

Drive face boss

Movable drive face

Weight roller

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8. "V" Type Belt Drive System/Kick-Starter

8-9

Check if movable drive face boss is worn or
damage and replace it if necessary.
Measure the outer diameter of drive face boss,
and replace it if it exceed service limit.

Service limit: 19.98 mm

Measure the inner diameter of drive face, and
replace it if it exceed service limit.

Service limit: 20.120 mm

Reassembly / Installation

Install weight rollers.

Install ramp plate.

Apply with some grease to inside of movable
drive face, and install drive face boss.

Caution

 The drive face has to be free of grease.

Clean it with cleaning solvent.

Weight roller

Drive face boss

Ramp plate

Drive face

Movable drive face

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8. "V" Type Belt Drive System/Kick-Starter

8-10

Install movable drive face assembly onto
crankshaft.

Drive Face Installation

Press drive belt into pulley groove, and then pull
the belt on to crankshaft.

Install drive face, washer and nut.

Caution

 Make sure that two sides of drive face have

to be free of grease. Clean it with cleaning
solvent.

Hold flywheel with universal holder.

Tighten nut to specified torque.

Torque value: 5.5~6.5kgf-m

Install left crankcase cover.

Drive belt

Universal holder

Nut

Drive face

Flywheel

Press down

Movable drive face

Crankshaft

Drive face boss

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8. "V" Type Belt Drive System/Kick-Starter

8-11

Clutch/Driven Pulley

Disassembly

Remove drive belt and clutch/driven pulley.
Install clutch spring compressor onto the pulley
assembly, and operate the compressor to let nut
be installed more easily.

Special tool:
Clutch spring compressor

SYM-2301000

Clutch nut wrench

SYM-9020200

Caution

 Do not press the compressor too much.

Hold the clutch spring compressor onto bench
vise, and then remove mounting nut with clutch
nut wrench.
Release the clutch spring compressor and
remove clutch and spring from driven pulley.

Remove socket from sliding pulley.

Remove guide pin, guide pin roller, and driven
pulley, and then remove O-ring & oil seal seat
from sliding pulley.

Inspection
Clutch outer

Measure the inner diameter of clutch outer friction
face. Replace clutch outer if exceed service limit.

Service limit: 107.5 mm

Socket

Or

Clutch nut
wrench

Clutch spring
compressor

Clutch outer

Inner
diameter

O-ring

Oil seal

Guide pin

Sliding pulley

Guide pin roller

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8. "V" Type Belt Drive System/Kick-Starter

8-12

Clutch weight

Measure each clutch weight thickness. Replace
it if exceeds service limit.

Service limit: 2.0 mm

Driven pulley spring

Measure the length of driven pulley spring.
Replace it if exceeds service limit.

Service limit: 82.5 mm

Driven pulley

Check following items:

 If both surfaces are damage or wear.
 If guide pin groove is damage or wear.

Replace damaged or worn components.
Measure the outer diameter of driven pulley and
the inner diameter of sliding pulley. Replace it if
exceeds service limit.

Service limit: Outer diameter 33.94 mm

Inner diameter 34.06 mm

Driven Pulley Bearing Inspection

Check if the inner bearing oil seal is damage.
Replace it if necessary.
Check if needle bearing is damage or too big
clearance. Replace it if necessary.
Rotate the inside of inner bearing with fingers to
check if the bearing rotation is in smooth and
silent. Check if the bearing outer parts are
closed and fixed. Replace it if necessary.

Caution

 Some of models are equipped with two ball

bearings.

Free length

Clutch weight

Needle bearing

Outer ball bearing

Sliding pulley

Driven pulley

Guide pin groove

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8. "V" Type Belt Drive System/Kick-Starter

8-13

Clutch Block Replacement

Remove clip and washer, and then remove clutch
weight and spring from drive plate.

Caution

 Some of models are equipped with one

mounting plate instead of 3 snap clips.

Check if spring is damage or insufficient elasticity.

Check if shock absorption rubber is damage or
deformation. Replace it if necessary.
Apply with grease onto lock pins.

Install new clutch weight onto lock pin and then
push to specific location.
Apply with grease onto lock pins. But, the clutch
weight should not be greased. If so, replace it.

Caution

 Grease or lubricant will damage the clutch

weight and affect the weight’s connection
capacity.

Install the spring into groove with pliers.

Shock absorption
rubber

Drive plate

Snap clip

Spring

Shock absorption rubber

Clutch block

Clutch weight

Spring

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8. "V" Type Belt Drive System/Kick-Starter

8-14

Install snap clip and mounting plate onto lock pin.

Replacement of Driven Pulley Bearing

Remove inner bearing.

Caution

 If the inner bearing equipped with oil seal on

side in the driven pulley, then remove the oil
seal firstly.

 If the pulley equipped with ball bearing, it has

to remove snap clip and then the bearing.

Remove snap clip and then push bearing forward
to other side of inner bearing.

Place new bearing onto proper position and its
sealing end should be forwarded to outside.
Apply with specified grease.

Install new inner bearing.

Caution

 Its sealing end should be forwarded to

outside as bearing installation.



Install needle bearing with hydraulic presser.

Install ball bearing by means of hydraulic
presser or driver.

Install snap clip into the groove of drive face.
Align oil seal lip with bearing, and then install the
new oil seal (if necessary).

Clip

Snap clip

Sealing end

Inner bearing

Sealing end

Specified grease

Snap ring

Outer bearing

Inner ball bearing

Outer bearing

Snap clip

Inner needle bearing

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8. "V" Type Belt Drive System/Kick-Starter

8-15

Installation of Clutch/Driven Pulley
Assembly

Install new oil seal and O-ring onto sliding pulley.
Apply with specified grease to lubricate the inside
of sliding pulley.

Install sliding pulley onto driven pulley.
Install guide pin and guide pin roller.

Install socket.

Install driven pulley, spring and clutch into clutch
spring compressor, and press down the assembly
by turning manual lever until mounting nut that
can be installed.
Hold the compressor by bench vise and tighten
the mounting nut to specified torque with clutch
nut wrench.

Special tool:
Clutch spring compressor

SYM-2301000

Clutch nut wrench

SYM-9020200

Remove the clutch spring compressor.

Torque value: 5.0~6.0kgf-m

Install clutch/driven pulley and drive belt onto
drive shaft.

Oil seal

Specified grease

O-ring

Mounting nut

Socket

Clutch nut wrench

Clutch spring
compressor

Or

O-ring

Oil seal

Guide pin

Sliding pulley

Guide pin roller

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8. "V" Type Belt Drive System/Kick-Starter

8-16

9. Final Driving Mechanism

9-1

Maintenance Information···················· 9-2
Troubleshooting·································· 9-2
Disassembly of Final Driving Mechanism

······························································ 9-3

Inspection of Final Driving Mechanism

································································9-6
Bearing Replacement ···························9-7
Re-Assembly of Final Driving Mechanism

································································9-8

9

Home page

Contents

Bearing 6201

Bearing 6203

Bearing 6201

Bearing 6203

Oil seal 17xxxx30xxxx6

Bearing 6004UU

1.0~1.5kgf-m

2.4~3.0kgf-m

1.0~1.5kgf-m

Oil seal 27xxxx42xxxx7

9. Final Driving Mechanism

9-2

Maintenance Information

Limited usage of gear oil: gear oil #140
Recommended oil: Bramax serial oil.
Oil quantity: 120 c.c. (110 c.c. as replacement)

Torque Values:

Mission cover bolt 2.4~3.0kgf-m
Mission oil drain bolt 1.0~1.5kgf-m
Mission oil check bolt 1.0~1.5kgf-m

Special tools:

Inner type bearing puller SYM-6204020
Outer type bearing puller SYM-6204010
Final shaft oil seal installer SYM-9125500
Drive shaft oil seal installer SYM-9120200
Bearing driver 6201 SYM-9610001
Bearing driver 6203/6004UZ SYM-9620000
R. Crank shaft puller SYM-1130000-R
L. Crank shaft install bush SYM-1130010
Extension bush

SYM-1130031 (long)

Extension bush

SYM-1130032 (short)

Troubleshooting

Trouble Diagnosis
Engine can be started but scooter cannot be moved

1. Damaged drive gear

2. Burnt out or seized drive gear

Noise

1. Seized, worn or damage gear

2. Worn or loose bearing

Gear oil leaks

1. Excessive gear oil.

2. Worn or damage oil seal

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9. Final Driving Mechanism

9-3

Disassembly of Final Driving
Mechanism

Remove driven pulley
Remove oil drain bolt and filling bolt.
Drain gear oil out from gearbox.

Remove muffler and rear wheel.

Remove gearbox cover mounting bolts from the
clutch side (7 bolts).

Remove the cover from the rear wheel side.

Rear wheel nut

Oil filling hole

7 bolts

Oil draining hole

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9. Final Driving Mechanism

9-4

Remove final gear, final shaft and counter gear,
counter shaft.

Remove the drive shaft from left crankcase.

Caution

The bearing must be replaced when removing
the drive shaft.

Drive shaft is pulled out with it’s bearing, then
remove the bearing with bearing puller and shaft
protector.

Special tool:
Multi-functional bearing puller or Outer bearing
puller SYM-6204001
Shaft protector SYM-6204010

Remove drive shaft oil seal and bearing from left
crankcase.

Oil seal

Drive shaft

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Counter shaft

Final shaft

Outer bearing puller

9. Final Driving Mechanism

9-5

Remove final gear, final shaft and counter gear,
counter shaft.

Remove the drive shaft from left crankcase.

Caution

The bearing must be replaced when removing
the drive shaft.

Drive shaft is pulled out with it’s bearing, then
remove the bearing with bearing puller and shaft
protector.

Special tool:
Multi-functional bearing puller or Outer bearing
puller SYM-6204001
Shaft protector SYM-6204010

Remove drive shaft oil seal and bearing from left
crankcase.

Oil seal

Oil filling hole

Drive shaft

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Counter shaft

Final shaft

Outer bearing puller