KYMCO Active 50 Service Manual

ACTIVE 50

PREFACE

This Service Manual describes the
technical features and servicing
procedures for the KYMCO ACTIVE 50.

Section 1 contains the precautions for all
operations stated in this manual. Read
them carefully before starting any
operation.

Section 2 is the inspection/ adjustment
procedures, safety rules and service
information for each part, starting from
periodic maintenance.

Sections 3 and 4 state the servicing
procedures and cautions for the removal
and installation of lubrication and fuel
systems.

Sections 5 through 18 give instructions
for disassembly, assembly and inspection
of engine, chassis frame and electrical
equipment.

Most sections start with an assembly or
system illustration and troubleshooting
for the section. The subsequent pages
give detailed procedures for the section.

KWANG YANG MOTOR CO., LTD.

OVERSEAS SALES DEPARTMENT

OVERSEAS SERVICE SECTION

TABLE OF CONTENTS

GENERAL INFORMATION 1
INSPECTION/ADJUSTMENT 2
LUBRICATION SYSTEM 3
FUEL SYSTEM 4
ENGINE REMOVAL/INSTALLATION 5
CYLINDER HEAD/VALVES 6
CYLINDER/PISTON 7
ALTERANTOR/CAM CHAIN

TENSIONER

8

CLUTCH/GEAR SHIFT MECHANISM 9

ENGINE

CRANKCASE/CRANKSHAFT/KICK
STARTER/TRANSMISSION

10

FRONT WHEEL/SUSPENSION/
STEERING

11

REAR WHEEL/BRAKE/SUSPENSION 12
HYDRAULIC BRAKE 13

CHASSIS

FRAME COVER

14

IGNITION SYSTEM 15
CHARGING SYSTEM 16
STARTING SYSTEM 17

ELECTRICAL

EQUIPMENT

LIGHTS/INSTRUMENTS/SWITCHES

/

HORN/FUEL UNIT

18

Our company reserves right to make
any alteration in the design

.

The information and contents included
in this manual may be different from
the motorcycle in case specifications
are changed.

1. GENERAL INFORMATION

1-0

ACTIVE 50

1

__________________________________________________________________________________

__________________________________________________________________________________

__________________________________________________________________________________

__________________________________________________________________________________

__________________________________________________________________________________

GENERAL INFORMATION

__________________________________________________________________________________

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

1

1. GENERAL INFORMATION

1-1

ACTIVE 50

ENGINE SERIAL NUMBER

Location of Engine Serial Numbe

r

Location of Frame Serial Numbe

r

1. GENERAL INFORMATION

1-2

ACTIVE 50

SPECIFICATIONS

Motorcycle name & Model No. LCA7
Motorcycle name ACTIVE 50
Overall length (mm) 1995
Overall width (mm) 680
Overall height (mm) 1090
Wheel base (mm) 1275
Engine type 4 ∞
Displacement (cc) 49
Fuel type nonleaded gasoline

Front wheel 46.5
Rear wheel 58

Dry weight (kg)

Front wheel 48.5
Rear wheel 63.5

Gross weight(kg)

Front wheel 2.5-17

Tires

Rear wheel 2.75/17

Ground clearance (mm) 120

Bra k ing d i s t anc e ( m) 7under

Perform­ance

Min. turning radius
(mm)

3800(R/L)

Starting system

Starting motor &

kick starter
Type OHC
Cylinder arrangement Single cylinder
Combustion chamber type Semi-sphere
Valve arrangement Single cam, OHC
Bore x stroke (mm) φ52.4x 49.5
Compression ratio 8

Compression pressure
(kg/cm²)

13

Max. output 1.8/7000kw(r/min)
Max. torque 2.6/4500kgm/rpm

Open 0°

Intake
(1mm)

Close 35°

Engine

Open 30°

Port
timin

g

Exhaust
(1mm)

Close 5°

Intake 0.02mm

Valve clearanc

e

(cold)

Exhaust 0.02mm

Idle speed (rpm) 1700rpm

Lubrication type

Forced

p

ressure &

wet sump
Oil pump type Inner/Outer rotor
Oil filter type Wire gauze filter

Lubrication

System

Oil capacity 0.9 liter

Cooling Type Air cooling

Air cleaner type Wet, single
Fuel capacity 4liter

Type PIF
Piston dia. (mm) 14.9
Venturi dia.(mm) φ20equivalent

Fuel System

Carburetor

Throttle type Plunger type
Type CDI
Ignition timing 15±2°/1700rpm
Spark plug CHAMPION-P-PZ9HC

Ignition

System

Spark plug gap 0.6～0.7mm

Electrical

Equipment

Battery Capacity 12V5AH
Clutch Type Wet multi-disc clutch

Type Permanent gear m eshing
Operating method Foot operated
Type Cycle type

1st gear 2.92
2nd gear 1.67
3rd gear 1.17
4th gear 0.92

Power Drive System

Transmission Gear

Reduction
ratio

5th gear -------

Front Caster angle 27°
Axle Wheel base 1305

Tire pressure

Front 1.75

(kg/cm²)(2 riders)

Rear 2.25
Left 45°

Turning angle

Right 45°
Front Disk brake

Brake system
type

Rear Drum brake
Front Telescope

Damping

Device

Shock absorber
type

Rear Mono Shock

Frame type Back bone

Moving Device

1. GENERAL INFORMATION

1-3

ACTIVE 50

SERVICE PRECAUTIONS

 Make sure to install new gaskets, O-rings,

circlips, cotter pins, etc. when
reassembling.

 When tightening bolts or nuts, begin with

larger-diameter to smaller ones at several
times, and tighten to the specified torque
diagonally.

 Use genuine parts and lubricants.

 When servicing the motorcycle, be sure

to use special tools for removal and
installation.

 After disassembly, clean removed parts.

Lubricate sliding surfaces with engine oil
before reassembly.

1. GENERAL INFORMATION

1-4

ACTIVE 50

 Apply or add designated greases and

lubricants to the specified lubrication
points.

 After reassembly, check all parts for

proper tightening and operation.

 When two persons work together, pay

attention to the mutual working safety.

 Disconnect the battery negative (-)

terminal before operation.

 When using a spanner or other tools,

make sure not to damage the motorcycle
surface.

 After operation, check all connecting

points, fasteners, and lines for proper
connection and installation.

 When connecting the battery, the positive

(+) terminal must be connected first.

 After connection, apply grease to the

battery terminals.

 Terminal caps shall be installed securely.

1. GENERAL INFORMATION

1-5

ACTIVE 50

 If the fuse is burned out, find the cause

and repair it. Replace it with a new one
according to the specified capacity.

 After operation, terminal caps shall be

installed securely.

 When taking out the connector, the lock

on the connector shall be released before
operation.

 Hold the connector body when

connecting or disconnecting it.

 Do not pull the connector wire.

 Check if any connector terminal is

bending, protruding or loose.

Confirm
Capacity

1. GENERAL INFORMATION

1-6

ACTIVE 50

 The connector shall be inserted

completely.

 If the double connector has a lock,

lock it at the correct position.

 Check if there is any loose wire.

 Before connecting a terminal, check

for damaged terminal cover or loose
negative terminal.

 Check the double connector cover for

proper coverage and installation.

 Insert the terminal completely.
 Check the terminal cover for proper

coverage.

 Do not make the terminal cover opening

face up.

 Secure wire harnesses to the frame with

their respective wire bands at the
designated locations.
Tighten the bands so that only the
insulated surfaces contact the wire
harnesses.

Snapping!

1. GENERAL INFORMATION

1-7

ACTIVE 50

 After clamping, check each wire to make

sure it is secure.

 Do not squeeze wires against the weld or

its clamp.

 After clamping, check each harness to

make sure that it is not interfering with
any moving or sliding parts.

 When fixing the wire harnesses, do not

make it contact the parts which will
generate high heat.

 Route wire harnesses to avoid sharp

edges or corners. Avoid the projected
ends of bolts and screws.

 Route wire harnesses passing through the

side of bolts and screws. Avoid the
projected ends of bolts and screws.

N

o Contact !

1. GENERAL INFORMATION

1-8

ACTIVE 50

 Route harnesses so they are neither

pulled tight nor have excessive slack.

 Protect wires and harnesses with

electrical tape or tube if they contact a
sharp edge or corner.

 When rubber protecting cover is used to

protect the wire harnesses, it shall be
installed securely.

 Do not break the sheath of wire.
 If a wire or harness is with a broken

sheath, repair by wrapping it with
protective tape or replace it.

 When installing other parts, do not press

or squeeze the wires.

Do not pull
too tight!

Do not press o

r

squeeze the wire.

1. GENERAL INFORMATION

1-9

ACTIVE 50

 After routing, check that the wire

harnesses are not twisted or kinked.

 Wire harnesses routed along with

handlebar should not be pulled tight, have
excessive slack or interfere with adjacent
or surrounding parts in all steering
positions.

 When a testing device is used, make sure

to understand the operating methods
thoroughly and operate according to the
operating instructions.

 Be careful not to drop any parts.

 When rust is found on a terminal, remove

the rust with sand paper or equivalent
before connecting.

 Do not bend or twist control cables.

Damaged control cables will not operate
smoothly and may stick or bind.

Do you understand
the instrument? Is the
instrument set correctly?

Remove Rust !

1. GENERAL INFORMATION

1-10

ACTIVE 50

 Symbols:

The following symbols represent the
servicing methods and cautions included
in this service manual.

: Apply engine oil to the

specified points. (Use
designated engine oil for
lubrication.)

: Apply grease for

lubrication.

: Use special tool.

: Caution

: Warning

Grease

＊

Engine Oil

Special

1. GENERAL INFORMATION

1-11

ACTIVE 50

TORQUE VALUES

STANDARD TORQUE VALUES

Ite

m

Torque (kg-m

)

Ite

m

Torque (kg-m

)

5mm bolt, nut
6mm bolt, nut
8mm bolt, nut
10mm bolt, nut
12mm bolt, nut

0.45～0.6

0.8～1.2

1.8～2.0

3.0～4.0

5.0～6.0

5mm screw
6mm nut, 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

2.0～3.0

3.5～4.5

Torque specifications listed below are for important fasteners.

ENGINE

Item Quantity Thread

Torque (kg-m) Remarks

Kick plate bolt
R/L case bolt
Stopper shift bolt
Cam gear shift bolt
Pin guide bolt
Oil pump bolt
Clutch nut
Rotor oil nut
Rotor oil cover bolt
Motor bolt
Head stud bolt
Cam sprocket bolt
Head cover cap nut
Pivot cam chain bolt
Tensioner bolt
Cylinder head bolt
Hole TP cap nut
Plate L case screw
Sprocket drive bolt
Fly wheel nut
L cover bolt
Head side cover L bolt
Inlet pipe bolt
Carburetor bolt
Head stud bolt
Head side cover R bolt
R cover oil bolt
Filter hole cap
Outer starting

2
8
1
1
1
3
1
1
3
3
4
3
4
1
1
2
2
2
2
1
9
2
2
2
2
2
1
1
3

6
6
6
6
8

6
10
10

6

6

7

5

7

8
14

6

30.8
6
6

10

6
6
6
6
8
6

14

30.8
6

0.8～1.2

0.8～1.2

0.8～1.2

1.0～1.4

0.8～1.2

0.8～1.2

3.8～4.5

3.8～4.5

0.45～0.6

0.8～1.2

0.7～1.1

0.7～1.1

1.2～1.6

1.3～1.8

1.5～2.5

0.6～0.9

1.0～2.0

0.8～1.2

1.0～1.6

3.2～4.0

0.8～1.2

0.8～1.2

0.8～1.2

0.8～1.2

0.7～1.1

0.8～1.2

2.0～3.0

1.0～2.0

1.0～1.5

1. GENERAL INFORMATION

1-12

ACTIVE 50

FRAME

Item Quantity Thread Torque (kg-m) Remarks

Steering stem lock nut
Steering top cone race
Front axle nut
Rear axle nut

Rear shock absorber upper mount bolt
Rear shock absorber lower mount bolt

Rear fork pivot nut
Handlebar lock nut
Rear driven gear bolt
Rear brake panel nut
Intake pipe mounting bolt
Engine hanger upper nut
Engine hanger lower nut

1
1
1
1
1
1
1
1
4
1
2
1
1

25.4

25.4

14
16
10
10
12
10

8
8
6
1
1

6.0～9.0

0.5～1.3

5.5～7.0

6.0～8.0

3.0～4.0

3.0～4.0

5.5～7.0

6.0～9.0

1.8～2.0

1.8～2.5

1.8～2.5

1.8～2.5

1.8～2.5

SPECIAL TOOLS

Tool Name Tool No. Ref. Page Remarks

Flywheel puller E003

8-4

Bearing puller 18mm E008

10-10

Lock nut socket wrench F007、E010、E049

9-5、11-16、11-18

Tappet adjuster E012

2-5

Oil seat & bearing install E014

10-11、11-9

Bearing puller 15mm E018

10-10

Bearing puller 12mm E020

10-10

Flywheel holder E021

8-3、8-7、9-6

Bearing puller 10mm E031

10-10

Clutch holder E039

9-5

Gear holder E038

9-9

Bearing driver handle & Bearing installer E014

11-9、11-17

Race cone install F005

1. GENERAL INFORMATION

1-13

ACTIVE 50

LUBRICATION POINTS

ENGINE

or CABLE LUBRICANT
SPEEDOMETER, THROTTLE, BRAKE CABLE

THROTTLE GRIP

SWING ARM
PIVOT VUSHINGS

CHAIN LUBRICANT
DRIVE CHAIN

BRAKE CAM

WHEEL BEARINGS

BRAKE PEDAL
PIVOT

CENTER & SIDE
STAND PIVOTS

SPEEDOMETER
GEAR

WHEEL BEARINGS

STEERING HEAD
BEARINGS

ENGINE

1. GENERAL INFORMATION

1-14

ACTIVE 50

CABLE & HARNESS ROUTING

Throttle Cable

Ignition Switch

Horn

Front brake
hose

1. GENERAL INFORMATION

1-15

ACTIVE 50

Winker Relay

Horn

Front Brake
Hose

Wire Harness

Ignition Coil

Ignition
Coil Wire

Starte

r

Motor

Regulator/
Rectifier

Choke Cable

1. GENERAL INFORMATION

1-16

ACTIVE 50

WIRING DIAGRAM

1. GENERAL INFORMATION

1-17

ACTIVE 50

TROUBLESHOOTING

ENGINE WILL NOT START OR IS HARD TO START

Empty fuel tank
Clogged carburetor fuel inlet
tube, vacuum tube or fuel tube
Clogged float oil passage
Clogged fuel filter
Clogged charcoal canister
Clogged auto fuel valve strainer
Faulty valve passage
Faulty fuel pump

Faulty spark plug
Fouled spark plug
Faulty CDI unit
Faulty pulser coil
Faulty exciter coil
Faulty ignition switch
Broken or shorted ignition coil
wire

Faulty or slipping clutch
Valve clearance too small
Valve stuck open
Worn cylinder and piston rings
Leaking cylinder head gasket

Faulty choke control system
Leaking intake manifold
Incorrect ignition timing
Incorrectly adjusted air screw

Flooded carburetor
Throttle valve excessively open
Clogged air cleaner

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

Probable Cause

Spark jumps

Normal

compression

Engine does not

fire

Weak or no spark

Low or no
compression

Engine fires but

does not start

Test cylinder
compression

Start engine by follow-

ing normal starting

procedure

Remove spark plug and

inspect again

Symptom

Fuel reaches

carburetor

Fuel does not

reach carburetor

Wet spark plug

Dry spark plug

1. GENERAL INFORMATION

1-18

ACTIVE 50

POOR PERFORMANCE (ESPECIALLY AT IDLE AND LOW SPEEDS)

Faulty CDI unit
Faulty pulser coil

Mixture too lean (turn screw in)
Mixture too rich (turn screw
out)

Faulty intake manifold gasket
Carburetor not securely
tightened
Damaged insulator rubber
Broken vacuum tube

Faulty or fouled spark plug
Faulty CDI unit
Faulty A.C. generator
Faulty ignition coil
Faulty ignition switch

Faulty A.C. generator
Damaged vacuum tube
Clogged air vent hole

Remove spark plug and
install it into spark plug

cap to test spark by

connecting it to engine

ground

Inspection/Adjustment Symptom

Probable Cause

Check ignition timing

Check A.C. generator

Check carburetor gasket

for air leaks

Check carburetor air

screw adjustment

Correct

Incorrect

Correctly adjusted

No air leak

Air leaks

Good spark

Weak or inter-

mittent s

p

ark

Good

Faulty

Incorrectly adjusted

1. GENERAL INFORMATION

1-19

ACTIVE 50

POOR PERFORMANCE (ENGINE LACKS POWER)

Clogged air cleaner
Poor fuel flow (Restricted)
Clogged fuel tank cap breather hole
Clogged exhaust muffler
Carburetor fuel level too low
Clogged carburetor high speed fuel
passage

Faulty CDI unit
Faulty pulser coil

Improper valve clearance
adjustment
Excessively worn valve seat
(protruded valve stem)

Improper valve and seat contact
Worn cylinder and piston rings
Leaking cylinder head gasket
Improper valve timing

Clean and unclog

Fouled spark plug
Incorrect heat range plug

Oil level too high
Oil level too low
Oil not changed

Clogged oil cooler
Clogged oil line
Faulty oil pump

Worn cylinder and piston rings
Mixture too lean
Poor quality fuel
Excessive carbon buildup in
combustion chamber
Ignition timing too advanced

Excessive carbon build-up in
combustion chamber
Poor quality fuel
Clutch slipping
Mixture too lean
Ignition timing too advanced

Start engine and accelerate
lightly for observation

Inspection/Adjustment

Symptom

Probable Cause

Engine speed

increases

Correc

t

Engine speed does no

t

increase sufficiently

Incorrec

t

Check ignition timing using
a timing light

Test cylinder compression

Check carburetor fo

r

clogging

Rapidly accelerate or run a

t

high speed

Remove spark plug and
inspect

Check for engine overheating

Check valve clearance

Correc

t

Incorrec

t

N

ormal

compression

Abnormal

compression

Check crankcase for oil
level and condition

Remove cylinder head oil
pipe bolt and inspect

Engine overheats

Engine does no

t

overheats

Plug not fouled o

r

discolored

Plug fouled o

r

discolored

Correct and no

t

contaminated

Incorrect o

r

contaminated

Valve train lubricated
properly

Valve train no

t

lubricated properly

Engine does not knock

Engine knocks

Not clogged

Clogged

1. GENERAL INFORMATION

1-20

ACTIVE 50

POOR PERFORMANCE (AT HIGH SPEED)

Faulty CDI unit
Faulty pulser coil

Improperly adjusted valve clearance
Worn valve seat

Empty fuel tank
Clogged fuel filter or tube
Clogged fuel tank cap breather
hole
Cracked fuel pump vacuum tube

Clean and unclog

Cam timing gear aligning marks
not aligned

Faulty spring

Inspection/Adjustment Symptom Probable Cause

Check ignition timing

Check carburetor for

clogged jets

Check fuel filter for

fuel supply

Correct

Incorrect

Check valve spring

tension

Check valve clearance

Fuel flows freely

Fuel f l o w restricted

Correct

Incorrect

Not clogged

Clogged

Correct

Incorrect

Not weakened

Weak spring

Check valve timing

1. GENERAL INFORMATION

1-21

ACTIVE 50

POOR CHARGING (BATTERY OVER DISCHARGING OR OVERCHARGING)
Undercharging

Dead battery
Faulty battery

Faulty coil
Broken pink and yellow wires
Shorted pink and yellow wires

Broken red wire

Faulty regulator/rectifier
Poorly connected coupler

Faulty A.C. generator

Overcharging

Broken black wire

Poorly connected coupler

Faulty regulator/rectifier

Start engine and test
limit voltage between
battery terminals

Connect battery (+) wire
to regulator/rectifier
coupler red wire and
battery (-) wire to engine
ground and test voltage

Inspection/Adjustment

Inspection/Adjustment

Symptom

Symptom

Probable Cause

Probable Cause

Normal voltage

B

attery has voltage
with ignition switch
“ON”

Normal

Voltage does no

t

increase

B

attery has no
voltage with ignition
switch “ON”

Resistance too high

Normal voltage

No voltage

Measure resistance
between AC generator
coil terminals

Normal

Abnormal

Check regulator/rectifier
coupler for loose
connection

Normal

Abnormal

Connect battery (+) wire
to regulator/rectifier
coupler black wire and
battery (-) wire to engine
ground and test voltage

Check regulator/rectifier
coupler for loose
connection

1. GENERAL INFORMATION

1-22

ACTIVE 50

NO SPARK AT SPARK PLUG

Faulty old spark plug

Loose spark plug cap

Poorly connected coupler

Faulty ignition switch
Faulty exciter coil
Faulty pulser coil
Faulty ignition coil

Broken wire harness
Poorly connected coupler

Faulty CDI unit

Faulty ignition coil

Replace with a new spark

p

lug and inspect again

Check CDI unit coupler
for looseness

Inspection/Adjustment Symptom

Probable Cause

Normal

Abnormal

Normal

Abnormal

Normal

Abnormal

Abnormal

Measure resistance
between CDI unit
coupler wire terminals

Check related parts

Check ignition coil with
a CDI unit tester

Weak or no spark

Not loose

Good spark

Loose

Normal

Abnormal

Check spark plug cap
and ignition coil wire for
looseness

Check CDI unit with a
CDI unit tester

2. INSPECTION/ADJUSTMENT

2-0

ACTIVE 50

2

__________________________________________________________________________________

__________________________________________________________________________________

__________________________________________________________________________________

__________________________________________________________________________________

__________________________________________________________________________________

INSPECTION/ADJUSTMENT

__________________________________________________________________________________

SERVICE INFORMATION------------------------------------------------ 2- 1
MAINTENANCE SCHEDULE-------------------------------------------- 2- 2
FUEL LINE/FILTER-------------------------------------------------------- 2- 3
THROTTLE OPERATION/CHOKE-------------------------------------- 2- 3
AIR CLEANER -------------------------------------------------------------- 2- 4
SPARK PLUG---------------------------------------------------------------- 2- 4
VALVE CLEARANCE----------------------------------------------------- 2- 5
CARBURETOR IDLE SPEED -------------------------------------------- 2- 5
IGNITION TIMING--------------------------------------------------------- 2- 6
CYLINDER COMPRESSION--------------------------------------------- 2- 6
ENGINE OIL----------------------------------------------------------------- 2- 7
DRIVE CHAIN -------------------------------------------------------------- 2- 7
CLUTCH---------------------------------------------------------------------- 2- 8
BRAKE SHOE --------------------------------------------------------------- 2- 8
BRAKE FLUID -------------------------------------------------------------- 2- 8
SUSPENSION---------------------------------------------------------------- 2- 9
NUTS/BOLTS/FASTENERS ---------------------------------------------- 2- 9
WHEELS/TIRES ------------------------------------------------------------ 2- 9
STEERING HANDLEBAR ------------------------------------------------ 2-10

2

2. INSPECTION/ADJUSTMENT

2-1

ACTIVE 50

SERVICE INFORMATION

GENERAL

！ WARNING

•Before running the engine, make sure that the working area is well-ventilated. Never run the
engine in a closed area. The exhaust contains poisonous carbon monoxide gas which may
cause death to people.

•Gasoline is extremely flammable and is explosive under some conditions. The working area
must be well-ventilated and do not smoke or allow flames or sparks near the working area or
fuel storage area.

SPECIFICATIONS
ENGINE CHASSIS

Throttle grip free play : 2～6mm Front brake free play: 10～20mm
Spark plug gap : 0.6～0.7mm Rear brake free play : 20～30mm
Spark plug specification : NGK–DR8EA Brake fluid : DOT-4
Valve clearance : IN: 0.02mm

EX: 0.02mm
Cylinder compression : 13±2kg/cm²
Ignition timing : 15±2°/1700rpm

Idle speed : 1700±100rpm
Engine oil capacity:
At disassembly : 1.0 liter
At change : 0.9 liter

TIRE PRESSURE

1 Rider 2 Riders

Front 1.75kg/cm² 2.0kg/cm²

Rear 2.25kg/cm² 2.25kg/cm²

TIRE SIZE:
Front : 2.5-17
Rear : 2.75-17

TORQUE VALUES

Front axle nut 5.5～7.0kg-m
Rear axle nut 6.0～8.0kg-m

2. INSPECTION/ADJUSTMENT

2-2

ACTIVE 50

MAINTENANCE SCHEDULE

Perform the periodic maintenance at each scheduled maintenance period.
I: Inspect, and Clean, Adjust, Lubricate, Refill, Repair or Replace if necessary.
A: Adjust C: Clean R: Replace T : Tighten

Regular Service Mileage (km)

Frequenc

y

Item

comes
first

Ö

Ø

1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 11000 12000

Engine oil

R

RRRRR

RRR

RRR

Engine oil filter
screen

CC C C

Fuel filter screen Replace at every 5000km
Valve clearance Inspect at every 3000km and adjust if necessary
Carburetor I I I I
Air Cleaner Note 2,3 C C C
Spark plug Clean at every 2000km and replace at every 5000km
Brake system I I I I I I
Drive chain A A A A A A
Suspension I I I I
Nuts, bolts, fasteners Inspect at every 8000km
Tire I I I I
Steering head bearing I I I I

• In the interest of safety, we recommend these items should be serviced only by an authorized

KYMCO motorcycle dealer.
Note: 1. For higher odometer readings, repeat at the frequency interval established here.

2. Service more frequently when riding in dusty or rainy areas.

3. Service more frequently when riding for long distance, in rain or at full throttle.

Whicheve

r

2. INSPECTION/ADJUSTMENT

2-3

ACTIVE 50

FUEL LINE/FILTER

Check the fuel lines and replace any parts
which show signs of deterioration, damage
or leakage.

THROTTLE OPERATION

Check for smooth throttle grip movement in
all steering positions.
Measure the throttle grip free play.

Free Play: 2～6mm

Adjust the throttle grip free play by turning
the adjusting nut on the throttle cable.
Slide the dust boot out and adjust by
loosening the lock nut and turning the
adjusting nut.

CHOKE

Check choke lever operation.
If the choke lever moves stiffly, clean and

lubricate the pivot.
After cleaning, recheck the lever movement.

Lock Nu

t

Adjusting Nu

t

Dust Boo

t

Do not smoke or allow flames or sparks
in your working area.

＊

Fuel Filte

r

2. INSPECTION/ADJUSTMENT

2-4

ACTIVE 50

Gap, Wear, and
Fouling Deposits

AIR CLEANER

AIR CLEANER REPLACEMENT

Remove the right center cover. (page 14-3)
Remove the air cleaner case. (page 4-5)
Remove the air cleaner case cover screws
and the cover. (page 4-5)
Remove the air cleaner screen and element.
Check the element and replace it with a new
one if it is excessively dirty or damaged.

CHANGE INTERVAL

Wash the air cleaner element in detergent oil,
squeeze out and allow to dry.

After washing, soak the element in clean
engine oil SAE 15W-40# and squeeze out
excess oil. Reinstall the element.

SPARK PLUG

Remove the spark plug.
Check the spark plug for wear, damage and
fouling deposits.
Clean any fouling deposits with a spark plug
cleaner or a wire brush.

Specified Spark Plug: CHAMPION-P-PZ9HC

Measure the spark plug gap.
Spark Plug Gap: 0.6～0.7mm

Cracks
Damage

Squeeze ou

t

and dry

Air Cleaner Case

Washe

r

Deformation

Spark Plug

Air Cleaner Case Cove

r

Wash

Engine
oil

Squeeze ou

t

and dry

Never use gasoline or organic vaporable

oil with acid or alkali for washing.

＊

0.6～0.7m

m

When installing, first screw in the spar

k

plug by hand and then tighten it with a
spark plug wrench.

＊

Choke Leve

r

2. INSPECTION/ADJUSTMENT

2-5

ACTIVE 50

VALVE CLEARANCE

Remove the cylinder head cover.

Rotate the generator flywheel to locate the
camshaft on the top dead center (TDC) and
align the “T” mark on the flywheel with the
mark on the left crankcase cover.

Inspect and adjust the valve clearance.
Valve Clearance: IN : 0.02mm

EX: 0.02mm

Loosen the lock nut and adjust by turning the
adjusting bolt.

Tappet adjuster E012

CARBURETOR IDLE SPEED

Turn the throttle stop screw to obtain the
specified idle speed.

Idle Speed: 1700±100rpm
When the engine misses or run erratic, adjust

the air screw.

Throttle Stop Screw

“T” Mark

Bolts

Air Screw

Inspect and adjust valve clearance while
the engine is cold (below 35℃).

＊

After adjustment, rotate the crankshaft
several turns to make sure that the valve
clearance is correct.

＊

Check the valve clearance again after the
lock nut is tightened.

＊

The engine must be warm for accurate
idle speed inspection and adjustment.

＊

When adjusting the carburetor, make
sure to use a E/M tester.

＊

Cylinder Head Cove

r

Special

2. INSPECTION/ADJUSTMENT

2-6

ACTIVE 50

IGNITION TIMING

Remove the ignition timing eye hole cap on
the left crankcase cover.

Check the ignition timing with a timing light.
When the engine is running at idle speed, the
ignition timing is correct if the index mark
on the left crankcase cover aligns with the
“F” mark on the flywheel.

CYLINDER COMPRESSION

Warm up the engine before compression test.
Stop the engine, then remove the spark plug
and insert a compression gauge.
Open the throttle valve fully and crank the
engine with the starter motor or kick lever.
Measure the compression.

Compression: 13±2kg/cm²

If the compression is low, check for the
following:

‧Leaky valves
‧Valve clearance to small
‧Leaking cylinder head gasket
‧Worn piston rings
‧Worn piston/cylinder

If the compression is high, it indicates that
carbon deposits have accumulated on the
combustion chamber and the piston head.

Compression Gauge

Timing Ligh

t

Eye Hole

“F” Mark

• The CDI unit is not adjustable.

• If the ignition timing is incorrect,

check the ignition system.

＊

2. INSPECTION/ADJUSTMENT

2-7

ACTIVE 50

ENGINE OIL

After the engine is stopped for 10 minutes,
check if the oil level is between the upper and
lower limits.
If the oil level is low, add the recommended
oil to the proper level.

Recommended Oil: SAE15W40#

API: SG

After oil change, be sure to tighten the drain
bolt securely.
Check the drain bolt washer for damage.

Oil Capacity: At disassembly : 1.0 liter

At change : 0.9 liter

DRIVE CHAIN

Check the drive chain slack.
Specified Slack: 1～2cm
Drive Chain Adjustment:

1. Loosen the rear axle nut.

2. Adjust the right and left adjusting nuts to

align the right punch mark with the left
punch mark.

3. Turn the rear wheel to see if the drive

chain slack is within the specified range.

4. Tighten the rear axle nut.

Punch Mark

Rear Axle Nu

t

Adjusting Nu

t

When checking the oil level, place the
motorcycle on its main stand on level
ground for oil level check.

＊

After drive chain adjustment, check the
rear brake pedal free play and adjust if
necessary.

＊

Upper Limit

Lower Limit

Drain Bol

t

2. INSPECTION/ADJUSTMENT

2-8

ACTIVE 50

BRAKE SHOE

Inspect the front brake linings for wear.

BRAKE LEVER/PEDAL

Measure the rear brake pedal free play.

Free Play: 20～30mm

CLUTCH

Stop the engine.
Loosen the lock nut.
Slowly turn the adjusting bolt
counterclockwise and stop when resistance is
felt,
From this point, turn the adjusting bolt
clockwise 1/8 turn and tighten the lock nut,
Check that the clutch is not slipping and is
properly disengaging.

BRAKE FLUID

Turn the steering handlebar upright and
check if the brake fluid level is between the
upper and lower limits.

Specified Brake Fluid: DOT-4

Lower Limi

t

Lock Nu

t

Adjusting Bol

t

2. INSPECTION/ADJUSTMENT

2-9

ACTIVE 50

SUSPENSION

FRONT

Fully apply the front brake lever and check
the action of the front shock absorbers by
compressing them several times.
Check the entire shock absorber assembly
for oil leaks, looseness or damage.

REAR

Check the action of the rear shock absorber
by compressing it several times.
Check the entire shock absorber assembly
for oil leaks, looseness or damage.
Jack the rear wheel off the ground and move
the rear wheel sideways with force to see if
the engine hanger bushings are worn.

NUTS/BOLTS/FASTENERS

Check all important chassis nuts and bolts
for looseness.
Tighten them to their specified torque values
if any looseness is found.

WHEELS/TIRES

Check the tires for cuts, imbedded objects or
other damages.
Check the tire pressure.

TIRE PRESSURE

1 Rider 2 Riders

Front 1.75kg/cm² 1.75kg/cm²
Rear 1.75kg/cm² 2.25kg/cm²

TIRE SIZE

Front: 2.5-17
Rear: 2.75-17

Tire Pressure Gauge

Tire pressure should be checked when
tires are cold.

＊

2. INSPECTION/ADJUSTMENT

2-10

ACTIVE 50

Check the front and rear axle nuts for
looseness.
If the axle nuts are loose, tighten them to the
specified torques.

Torques: Front : 5.5～7.0kg-m

Rear : 6.0～8.0kg-m

STEERING HANDLEBAR

Check that the control cables do not interfere
with handlebar rotation.
Raise the front wheel off the ground and
check that the steering handlebar rotates
freely.
If the handlebar moves unevenly, binds, or
has vertical movement, adjust the steering
head bearing.

Front Axle Nu

t

3. LUBRICATION SYSTEM

3-0

ACTIVE 50

3

__________________________________________________________________________________

__________________________________________________________________________________

__________________________________________________________________________________

__________________________________________________________________________________

__________________________________________________________________________________

LUBRICATION SYSTEM

__________________________________________________________________________________

SERVICE INFORMATION------------------------------------------------ 3- 2
TROUBLESHOOTING----------------------------------------------------- 3- 2
ENGINE OIL/OIL FILTER ------------------------------------------------ 3- 3
OIL PUMP/OIL FILTER ROTOR ---------------------------------------- 3- 4

3

3. LUBRICATION SYSTEM

3-1

ACTIVE 50

3. LUBRICATION SYSTEM

3-2

ACTIVE 50

SERVICE INFORMATION

GENERAL INSTRUCTIONS

• The service and maintenance of this section can be performed with the engine installed in the

frame.

• Use care when removing and installing the oil pump not to allow dust and foreign matters to

enter the engine and oil line.

• The oil pump must be replaced as a set when it reaches its service life.

• After the oil pump is installed, check each part for oil leaks and improper lubrication.

• When removing and installing the oil cooler, be careful not to bend or deform the oil pipe.

SPECIFICATIONS

Item Standard (mm) Service Limit (mm)

Tip clearance ─ 0.20

Oil pump Body clearance ─ 0.20

End clearance 0.10～0.15 0.15

TROUBLESHOOTING

Oil level too low Engine burns

• External oil leak • Oil not changed often enough

• Worn valve guide or seal • Head gasket faulty

• Worn piston rings • Worn piston rings

3. LUBRICATION SYSTEM

3-3

ACTIVE 50

ENGINE OIL/OIL FILTER

OIL LEVEL

Check the oil level. If the level is near the
lower limit, fill to the upper limit with the
specified engine oil.

OIL CHANGE

Remove the drain bolt to drain the engine oil
thoroughly.
Check the drain bolt washer for damage or
deformation and replace with a new one if
necessary.

ENGINE OIL FILTER

Remove the right crankcase cover attaching
bolts and right crankcase cover.
Remove the dowel pins and gasket.

Clean oil filter screen.

Specified Oil: SAE15W40
API service classification: SG
Oil Capacity: At disassembly : 1.0 liter

At change : 0.9 liter
Check for oil leaks and then start the engine
and let it idle for few minutes.
Stop the engine and recheck the oil level.

Lower Limi

t

Drain Bol

t

Oil Filter Screen Ca

p

• Place the motorcycle upright on level
ground for engine oil level check.

• Run the engine for 2～3 minutes and
check the oil level after the engine is
stopped for 2～3 minutes.

＊

Upper Limi

t

The engine oil will drain more easily
while the engine is warm.

＊

Bolts

3. LUBRICATION SYSTEM

3-4

ACTIVE 50

Right Crankcase Cove

r

Gasge

t

Pump Cove

r

Oil Filter Rotor Cove

r

OIL PUMP/OIL FILTER ROTOR

REMOVAL

Remove the right crankcase cover (page 9-3)

OIL FILTER ROTOR

Remove the filter rotor cover and gasket
(pqge 9-3).

Clean the oil filter rotor cover and rotor.
Install the oil filter rotor cover (page 9-9).
Install the right crankcase cover (page 9-11).

OIL PUMP

Remove the oil drain bolt and drain the oil
from the engine (page 3-3).

Remove the right crankcase cover (page 9-

3).
Remove the clutch drum (page 9-3)
Remove the three oil pump mounting bolts

and oil pump.

DISASSEMBLY

Remove the three cover screws and cover.
Remove the rotor shaft.
Remove the inner and outer rotors from the

pump body.
Clean the disassembled parts in non-

flammable or high flash-point solvent.
Check all parts for damage or wear.

Oil Filter Roto

r

Oil Pump Mounting Bolts

Screws

When installing, make sure to use a new
right crankcase cover gasket.

＊

The oil pump can be removed with the
engine mounted in the frame.

＊

3. LUBRICATION SYSTEM

3-5

ACTIVE 50

INSPECTION

Install the drive shaft and rotors.
Measure the rotor tip clearance.

Service limit: 0.2mm

Measure the pump body clearance.
Service limit: 0.2mm

Install the gasket and measure the rotor end
clearance.

Service limit: 0.15mm

OIL PUMP ASSEMBLY

Install the outer and inner rotors.
Insert the drive shaft and align the flat on the
shaft with the flat in the inner rotor,

Inner Roto

r

Outor Roto

r

Drive Shaf

t

Align Flats

Pump Body

3. LUBRICATION SYSTEM

3-6

ACTIVE 50

Gaske

t

Pump Cove

r

Oil Pump Mounting Bolts

Cover Screws

Gaske

t

Cam Chain Guide Spindle

Drive Shaf

t

Install a new pump body cover gasket and
the cover.

INSTALLATION

Install the oil pump with a new gasket under
it by aligning the slot if the drive shaft with
the cam chain guide spindle.

Tighten the oil pump mounting bolts
securely.
Check the cover screws for loose, retighten if
necessary.

Install the right crankcase cover, kick starter
pedal.

Fill the crankcase with the recommended
engine oil.

Make sure that the pump rotates freely
without binding.

＊

4. FUEL SYSTEM

4-0

ACTIVE 50

4

_____________________________________________________________________________________________

_____________________________________________________________________________________________

_____________________________________________________________________________________________

_____________________________________________________________________________________________

_____________________________________________________________________________________________

FUEL SYSTEM

_____________________________________________________________________________________________

SERVICE INFORMATION ------------------------------------------------ 4- 2
TROUBLESHOOTING----------------------------------------------------- 4- 3
AIR CLEANER REMOVAL----------------------------------------------- 4-4
THROTTLE VALVE DISASSEMBLY----------------------------------- 4- 5
THROTTLE VALVE INSTALLATION ---------------------------------- 4- 6
CARBURETOR REMOVAL----------------------------------------------- 4- 7

4

4. FUEL SYSTEM

4-1

ACTIVE 50

4. FUEL SYSTEM

4-2

ACTIVE 50

SERVICE INFORMATION

GENERAL INSTRUCTIONS

• Do not bend or twist control cables. Damaged control cables will not operate smoothly.

• When disassembling fuel system parts, note the locations of O-rings. Replace them with new ones during

reassembly.

• Before float chamber disassembly, loosen the drain screw to drain the residual gasoline into a clean container.

• After the carburetor is removed, plug the intake manifold side with a clean shop towel to prevent foreign

matters from entering.

• The carburetor air jets and fuel jets must be cleaned with compressed air.

• When the motorcycle is not used for over one month, drain the residual gasoline from the float chamber to

avoid erratic idling and clogged slow jet due to deteriorated fuel.

SPECIFICATIONS

Item Standard
Carburetor type PIF
Venturi dia. φ11
Piston dia φ13.5
Main jet 77.5#
Idle speed 1700±100rpm
Throttle grip free play 2～6mm
Air screw opening 1¾±½

SPECIAL T OOL

Float level gauge

Gasoline is very dangerous. When working with gasoline, keep sparks and flames away from the
working area.

Gasoline is extremely flammable and is explosive under certain conditions. Be sure to
work in a well-ventilated area.

4. FUEL SYSTEM

4-3

ACTIVE 50

TROUBLESHOOTING

Engine cranks but won’t start Engine lacks power

• No fuel in tank • Clogged air cleaner

• No fuel to carburetor • Faulty carburetor

• Cylinder flooded with fuel • Faulty ignition system

• No spark at plug

• Faulty fuel pump

• Clogged air cleaner Lean mixture

• Intake air leak • Clogged carburetor fuel jets

• Improper throttle operation • Float level too low

• Intake air leak

Engine idles roughly, stalls or runs poorly • Faulty charcoal canister

• Faulty charcoal canister • Restricted fuel line

• Ignition malfunction

• Faulty carburetor Rich mixture

• Poor quality fuel • Float level too low

• Lean or rich mixture • Clogged air jets

• Clogged air cleaner • Clogged air cleaner

• Incorrect idle speed

• W orn throttle needle

Misfiring during acceleration

• Faulty ignition system

• Faulty carburetor

• Faulty accelerating pump

• Faulty charcoal canister

Backfiring at deceleration

• Float level too low

• Incorrectly adjusted carburetor

• Faulty exhaust muffler

4. FUEL SYSTEM

4-4

ACTIVE 50

AIR CLEANER REMOVA L

Remove the front cover (page 14-3).
Remove the screw attaching the carburetor.
Remove the air cleaner case by removing the
attaching bolts.

.
Remove the four screws with the air cleaner case
cover.

Remove the element and the element holder
from the air cleaner case.

INSTALLATION

Install the air cleaner case in the reverse order of
removal.

Screw

Screw

Element

Element Holde

r

Air Cleaner Case Cover

Bolt

4. FUEL SYSTEM

4-5

ACTIVE 50

THROTTLE VALVE DIS­ASSEMBLY

Remove the front cover (page 14-3).
Loosen the carburetor cap and remove the
throttle valve.

Disconnect the throttle cable from the
throttle valve.

Remove the throttle valve, spring and carburetor
top.

Remove the jet needle by removing the
needle clip.
Check the jet needle and throttle valve for
wear or damage.

Carburetor Cap

Throttle Valve

Throttle Valve

Jet Needle

Needle Clip

Spring

Throttle Cable

Throttle Valve

The carburetor top is an integral part of the

throttle cable assembly. The top can not be
separated from the assembly without causing
damage to the cable.

＊

4. FUEL SYSTEM

4-6

ACTIVE 50

THROTTLE VALV E INSTALLA­TION

Set the needle clip on the jet needle clip.
Standard podition: 3rd groove from the top
Install the jet needle on the throttle valve.
Install the retainer on the throttle valve and secure
the jet needle.

Install the throttle cable to the throttle valve
while depressing the throttle valve spring.

Insert the throttle valve into the carbu reto r, aligning
the throttle valve groove with the throttle stop
screw.

Install the carburetor top onto the carburetor.

Throttle Valve

Throttle Cable

Carburetor T op

Throttle Valve Spring

Groove

Carburetor T op

After installing the carburetor and
throttle valve, perform the following
adjustments:

-Throttle grip free play (page 2-3).

-Carburetor air screw adjustment if the
carburetor was overhauled or cleaned.

＊

4. FUEL SYSTEM

4-7

ACTIVE 50

CARBURETOR REMOVAL

Remove the front cover (page 14-3).

Loosen the air cleaner connecting tube band.

Remove the carburetor top (page 4-6).

Remove the fuel tube from the carburetor.

Remove the choke cable.
Remove the carburetor mounting bolts.
Remove the insulator, O-ring and carburetor.

CARBURETOR DISASSEMBLY

Loosen the drain screw to drain the gasoline from
the float chamber.

Bolts

Drain Screw

Fuel Tube

Choke Cable

Carburetor top

• Keep sparks and flames away from the work
area.

• Drain gasoline into a clean container.

＊

4. FUEL SYSTEM

4-8

ACTIVE 50

Float/Float Valve Disassembly

Remove the four float chamber attaching screws
and remove the float chamber.

Remove the float pin, float and float valve.

FLOA T/FLOAT VAL VE INSPECTION

Inspect the float valve seat for wear or damage.

Inspect the float for damage or fuel level
inside the float chamber.

MAIN JET/SLOW JETS/AIR
SCREW/THROTTLE STOP SCREW
REMOVAL

Remove the main jet, needle jet holder, and needle
jet.
Remove the slow jet.

Float Pin

Floa

t

Slow Je

t

Screws

Float Valve Sea

t

N

eedle Je

t

N

eedle Jet Holde

r

Main Je

t

4. FUEL SYSTEM

4-9

ACTIVE 50

Remove the air screw and throttle stop screw.

CAUTIONS !

Carburetor Cleaning

Blow compressed air through all passages of the
carburetor body.

Slow Jet/Main Jet Installation

Install the slow jet.
Install the needle jet, needle jet holder and main jet.
Install the throttle stop screw and air screw.

Install the float valve, float and float pin.

Float Pin

Floa

t

Throttle Stop Screw

Air Screw

Throttle Stop Screw

Air Screw

Slow Je

t

N

eedle Je

t

N

eedle Jet Holde

r

Main Je

t

• Be careful not to damage the jets and jet
holder when removing them.

• Before removing, turn the throttle stop screw
and air screw in and carefully count the
number of turns until they seat lightly and
then make a note of this.

• Do not force the screw against its seat to
avoid seat damage.

• Be sure to install the O-ring in the reverse
order of removal.

＊

• When installing the air screw, return it to the
original position as noted during removal

• After the carburetor is installed, be sure to
perform the Exhaust Emission Test.

＊

4. FUEL SYSTEM

4-10

ACTIVE 50

FLOAT LEVEL INSPECTION

Turn the carburetor upside down so that the float
will go down to make the float valve contact the
float valve seat.

Then slowly tilt the carburetor and measure
the float level with the float level gauge
while the float pin just contacts with float
valve.

Float Level: 20mm

When adjusting, carefully bend the float pin.
Check the float for proper operation and then install
the float chamber.

CARBURETOR INSTALLATION

Install the carburetor onto the intake manifold and
tighten the two mounting bolts.
Install the fuel tube and the choke cable..

Torque: 0.8～1.2kg-m
Install the air cleaner connector and tighten the

band screw.

Assemble the carburetor top and throttle valve
spring.

Connect the throttle cable to the throttle
valve.

Float Level Gauge

Carburetor T op

Bol

t

Fuel Tube

Choke Cable

4. FUEL SYSTEM

4-11

ACTIVE 50

FUEL TANK

FUEL TANK REMOVAL

Turn the fuel valve to “OFF”.
Remove the three bolts attaching the rear
carrier.

Remove the four seat lock nuts.
Remove the tool box mounting bolt and tool box.
Disconnect the fuel strainer and remove the nuts on

the end of the fuel tank.
Disconnect the fuel unit wire connector and fuel
gauge wire.
Remove the fuel tank.

FUEL STRAINER REMOVAL

Remove the fuel strainer from the fuel tank.

INSPECTION

Inspect if the fuel strainer is clogged and
clean it with compressed air.

INSTALLATION

Install the fuel strainer with its arrow mark

toward the fuel pump.

FUEL TANK INST ALLATION

Install the fuel tank in the reverse order of removal.
Check that there is no fuel leakage.

Check the wire connectors for proper
connection.

• Keep sparks and flames away from the
work area.

• Wipe off any spilled gasoline.

• When removing the fuel strainer, do not

allow flames or sparks near the working area
and drain the residual gasoline into a
container.

＊

Warning

Fuel Unit Wire

Screw Fuel Straine

r

Fuel Unit Wire

Screw Fuel Straine

r

5. ENGINE REMOVAL/INSTALLATION

5-0

ACTIVE 50

5 .

__________________________________________________________________________________

__________________________________________________________________________________

__________________________________________________________________________________

__________________________________________________________________________________

__________________________________________________________________________________

ENGINE REMOVAL/INSTALLATION

__________________________________________________________________________________

SERVICE INFORMATION------------------------------------------------ 5- 1
ENGINE REMOVAL ------------------------------------------------------- 5- 2
ENGINE INSTALLATION ------------------------------------------------ 5- 3

5

5. ENGINE REMOVAL/INSTALLATION

5-1

ACTIVE 50

SERVICE INFORMATION

GENERAL INSTRUCTIONS

• A engine stand or floor jack is required to support and maneuver the engine.

• The following parts can be serviced with the engine installed in the frame:
⎯ Cylinder head/valves (Section 6)
⎯ Cylinder/piston (Section 7)
⎯ Alterantor/cam chain tensioner (Section 8)
⎯ Clutch/gear shift mechanism (Section 9)

• When removing and installing the engine, do not use a hammer or screw driver to strike or pry

the engine.

• Do not damage the crankcase mating surfaces and clean off all gasket materials from the mating
surfaces.

• After crankcase assembly, check that the transmission system operates smoothly.

• After engine installation, start the engine and check that the lubrication system is normal.

Engine oil capacity:
At disassembly : 1.0 liter
At change : 0.9 liter

TORQUE VALUES

Engine bracket bolt 2.0～2.5kg-m
Drive gear lock bolt 0.8～1.2kg-m
Exhaust muffler hanger lock bolt 2.4～3.0kg-m
Rear fork pivot nut 5.5～6.5kg-m
Exhaust muffler joint lock nut 0.8～1.2kg-m

5. ENGINE REMOVAL/INSTALLATION

5-2

ACTIVE 50

ENGINE REMOVAL

Remove the right and left decorative covers
under the seat.
Remove the carburetor (page 4-5).

Remove the two exhaust muffler joint lock
nuts.
Remove the exhaust muffler hanger lock bolt
and exhaust muffler.

Remove the spark plug cap.
Disconnect the A.C. generator wire

connector.

Loosen the rear axle nut and adjust the drive
chain slack (page 2-7).

Exhaust Muffle

r

Carbureto

r

Spark Plug Cap

Scre

w

Screw

• Drain the engine oil before engine
removal.

• The exhaust muffler temperature is
extremely high. Remove it when the
engine is cold.

＊

A.C. Generator Wire

Bol

t

Bol

t

5. ENGINE REMOVAL/INSTALLATION

5-3

ACTIVE 50

Remove the gear shift lever bolt and gear
shift lever.

Remove the two bolts attaching the left rear
crankcase cover and remove the rear
crankcase cover.

Remove the two bolts attaching the drive
gear set plate and the set plate.
Remove the drive gear and chain.

Remove the engine hanger nuts and pull out
the engine hanger bolts.

Remove the engine.

ENGINE INSTALLATION

Install the engine in the reverse order of
removal. Install the engine to its original
position with a jack or other adjustable
support.

Gearshift Pedal

Bolts

Rear Crankcase Cove

r

• When installing the engine, do not
damage the bolt thread and route the
wires and cables properly.

• Install the gear shift lever by align the
punch mark on the lever with that on
the spindle.

• Fill the crankcase to the proper level
with recommended engine oil.

• After installation, perform the following
inspections and adjustments:

1. Throttle operation

2. Drive chain adjustment

＊

Engine Hanger Bolt/Nu

t

Drive Chain Bolts Drive Gea

r

Set Plate

6. CYLINDER HEAD/VALVES

6-0

ACTIVE 50

6 .

__________________________________________________________________________________

__________________________________________________________________________________

__________________________________________________________________________________

__________________________________________________________________________________

__________________________________________________________________________________

CYLINDER HEAD/VALVES

__________________________________________________________________________________

SCHEMATIC DRAWING ------------------------------------------------- 6- 1
SERVICE INFORMATION------------------------------------------------ 6- 2
TROUBLESHOOTING----------------------------------------------------- 6- 3
CYLINDER HEAD REMOVAL ------------------------------------------ 6- 4
CYLINDER HEAD DISASSEMBLY ------------------------------------ 6- 5
CYLINDER HEAD ASSEMBLY----------------------------------------- 6- 8
CYLINDER HEAD INSTALLATION ----------------------------------- 6-10

6

6. CYLINDER HEAD/VALVES

6-1

ACTIVE 50

SCHEMATIC DRAWING

6. CYLINDER HEAD/VALVES

6-2

ACTIVE 50

SERVICE INFORMATION

GENERAL INSTRUCTIONS

• The cylinder head can be serviced with the engine installed in the frame. Coolant in the radiator
and water jacket must be drained first.

• When assembling, apply molybdenum disulfide grease or engine oil to the valve guide movable
parts and valve arm sliding surfaces for initial lubrication.

• The valve rocker arms are lubricated by engine oil through the cylinder head engine oil passages.
Clean and unclog the oil passages before assembling the cylinder head.

• After disassembly, clean the removed parts and dry them with compressed air before inspection.

• After removal, mark and arrange the removed parts in order. When assembling, install them in

the reverse order of removal.

Ite

m

Standard (mm) Service Limit (mm)

IN 0.02 0.04

EX 0.02 0.04
Cylinder head compression pressure 13kg/cm²
Cylinder head warpage

⎯

0.05

IN

⎯

25.8

EX

⎯

25.6

IN

⎯

10.

EX

⎯

10.

Valve rocker arm shaft IN

⎯

9.78

O.D. EX

⎯

9.78

IN 4.92～4.970 4.9

EX 4.90～4.950 4.9

IN

⎯

5.

EX

⎯

5.

Valve stem-to-guide IN

⎯

0.1

clearance EX

⎯

0.1

TORQUE VALUES

Cylinder head cap nut 1.0～2.0kg-m
Valve clearance adjusting nut 0.9kg-m
Cylinder head cover nut 1.2～1.6kg-m

SPECIAL TOOLS

Valve spring compressor

Valve clearance (cold)

Valve rocker arm I.D.

Valve stem O.D.

Camshaft cam height

Valve guide I.D.

6. CYLINDER HEAD/VALVES

6-3

ACTIVE 50

TROUBLESHOOTING

• The poor cylinder head operation can be diagnosed by a compression test or by tracing engine

top-end noises.

Poor performance at idle speed White smoke from exhaust muffler

• Compression too low • Worn valve stem or valve guide

• Damaged valve stem oil seal

Compression too low

• Incorrect valve clearance adjustment Abnormal noise

• Burned or bend valves • Incorrect valve clearance adjustment

• Incorrect valve timing • Sticking valve or broken valve spring

• Broken valve spring • Damaged or worn camshaft

• Poor valve and seat contact • Worn cam chain tensioner

• Leaking cylinder head gasket • Worn camshaft and rocker arm

• Warped or cracked cylinder head

• Poorly installed spark plug

Compression too high

• Excessive carbon build-up in combustion

chamber

6. CYLINDER HEAD/VALVES

6-4

ACTIVE 50

CYLINDER HEAD REMOVAL

Remove the left crankcase cover bolt.
Remove the left crankcase cover.
Remove the crankshaft hole cap and timing
hole cap.
Remove the left side cover and gasket.
Remove the cam chain tensioner sealing bolt,
washer, spring and tensioner shaft.(See the
diagramp6-4-4)
Remove the valve inspection hole caps.

Turn the crankshaft counterclockwise until
the “o” mark on the cam sprocket aligns with
the index mark on the cylinder head.

Make sure there slight clearances between the
valve stems and rocker arms by moving the
rocker arms up and down.

If the rocker arms are tight, turn the
crankshaft counterclockwise one full turn and
realign the “o” mark with the index mark.

Remove the cam sprocket bolts and cam
sprocket.

Loosen the cylinder bolts.
Remove the bolt attaching the cylinder head

to the cylinder,
Remove the four nuts holding the cylinder

head cover,
Remove the cylinder head cover.

Remove the cylinder head cover gasket.
Remove the cylinder head.
Remove the cylinder head gasket and dowel

pins.

Gaske

t

Inspection Hole Caps

• Suspend the cam chain with a wire o

r

cord to prevent it from falling into the
cylinder.

＊

Cylinder Head Cove

r

Cylinder Bol

t

N

uts And Washers Cy linder Head Bol

t

Left Side Cove

r

Tensioner Sealing Bol

t

Bol

t

Align

Bol

t

Cam Sprocke

t

6. CYLINDER HEAD/VALVES

6-5

ACTIVE 50

CYLINDER HEAD
DISASSEMBLY

Remove the two bolts and the right side
cover.

Screw a 8mm bolt into the rocker arm shaft,
and pull it out of the cylinder head.

Remove the rocker arms and camshaft from
the cylinder head.

While compressing the valve spring with a
valve spring compressor, remove the valve
cotters.

Loosen the valve spring compressor and
remove the valve retainers, valve springs,
spring seats, stem seals and valves.

Remove carbon deposits from the combustion
chamber.

Right Side Cove

r

Bolts

Valve Spring Compresso

r

• To prevent loss of tension, do not
compress the valve springs more than
necessary to remove the valve spring
cotters.

• Mark all parts to insure original
assembly.

＊

Rocker Arms

Camshaf

t

Rocker Arm Shaf

t

6. CYLINDER HEAD/VALVES

6-6

ACTIVE 50

Clean any gasket material from the cylinder
head mating surface.

CYLINDER HEAD INSPECTION

Check the spark plug hole and valve areas for
cracks.
Check the cylinder head for warpage with a
straight edge and feeler gauge.
Service Limit: 0.05mm repair or replace if
over

CAMSHAFT INSPECTION

Check each camshaft bearing for play or
damage. Replace the camshaft assembly with
a new one if the bearings are noisy or have
excessive play.

Check each cam lobe for wear or damage.
Measure the cam lobe height.

Service Limits:

IN: 25.8mm replace if below
EX:25.6mm replace if below

ROCKER ARM INSPECTION

Camshaft Bearing

Be careful not to damage the cylinde

r

head mating surface and valve seat.

＊

6. CYLINDER HEAD/VALVES

6-7

ACTIVE 50

Measure the I.D. of each valve rocker arm.
Service Limits: IN: 10. mm replace if over
EX: 10. mm replace if

over

ROCKER ARM SHAFT INSPECTION

Measure each rocker arm shaft O.D.
Service Limits: IN: 9.78mm replace if below

EX: 9.88mm replace if below

VALVE SPRING INSPECTION

Measure the free length of the inner and outer
valve springs.

Service Limits:
Inner (IN, EX) : 32.41mm replace if below
Outer (IN, EX): 35.25mm replace if below

VALVE /VALVE GUIDE INSPECTION

Inspect each valve for bending, burning,
scratches or abnormal stem wear.
Check valve movement in the guide.

Measure each valve stem O.D.
Service Limits:

IN: 4.90mm replace if below
EX: 4.90mm replace if below

Measure each valve guide I.D.

6. CYLINDER HEAD/VALVES

6-8

ACTIVE 50

Service Limits: IN: 5.00mm replace if over

EX: 5.00mm replace if over

Subtract each valve stem O.D. from the
corresponding guide I.D. to obtain the stem­to-guide clearance.
Service Limits: IN: 0.10mm replace if over

EX: 0.10mm replace if over

CYLINDER HEAD ASSEMBLY

Lubricate each valve stem with oil.
Insert the valves into the valve guides.

Install the valve spring seats and valve stem
seals.

Apply engine oil to the inside of the valve
stem seals and insert the valves into the valve
guides.

Install the valve springs and retainers.
Compress the valve springs using the valve
spring compressor, then install the valve
cotters.

Special Tool

Valve Spring Compressor

Tap the valve stems gently with a plastic
hammer to firmly seat the cotters.

If the stem-to-guide clearance exceeds
the service limits, replace the guides as
necessary. Reface the valve seats
whenever the valve guides are replaced.

＊

Be careful not to damage the valves.

＊

Valve

Outer Spring

Inner Spring

Stem Seal

Retaine

r

Valve Cotters

Be sure to install new valve stem seals.

＊

• When assembling, a valve spring
compressor must be used.

• Install the cotters with the pointed ends
facing down from the upper side of the
cylinder head.

＊

Install new valve stem seals when
assembling.

＊

6. CYLINDER HEAD/VALVES

6-9

ACTIVE 50

Coat the camshaft, camshaft bearings and
automatic decompressor cam with clean
engine oil.

Install the camshaft into the cylinder head
with the cam lobes facing the piston.

Install the rocker arms as shown.

Coat the rocker arm shafts with clean engine
oil.

Install the rocker arm shafts by screwing an 8
mm bolt into the thread end as shown.

Install a new Gasket on the right side cover.
Install the right side cover.

CYLINDER HEAD INSTALLATION

Clean the cylinder head gasket surface of any
gasket material.

Gaske

t

Rocker Arm Shafts

Camshaf

t

Rocker Arms

Be careful not to enter dust and dirt into
the cylinder.

＊

6. CYLINDER HEAD/VALVES

6-10

ACTIVE 50

Install the dowel pins and a new cylinder
head gasket.

Install the cylinder head.
Install the new cylinder head cover gasket.

Install the cylinder head cover with its arrow
mark facing the inlet side.

Install one copper washer and three washers.
Install the four cylinder head cover cap nuts,

cylinder head bolt and cylinder bolt.
Tighten the four cap nuts in a crisscross

pattern in 2-3 steps first, then tighten the
cylinder head bolt and cylinder bolt.

TORQUE
Cylinder head cover cap nut: 1.2～1.6kg-m
Cylinder head bolt: 0.6～0.9kg-m
Cylinder bolt: 0.6～0.9kg-m

Rotate the flywheel counterclockwise to align
the “T” mark on the cylinder head.

Install the cam chain over the cam sprocket,
and install the cam sprocket on the camshaft.

Install and tighten the cam sprocket bolts.
TORQUE: 0.7～1.1 kg-m

Install the left side cover Gasket on the left
side cover.

Install the left side cover.
Adjust the valve clearance.

Gaske

t

Gaske

t

Dowel Pins

Inspection Hole Caps

Cylinder Bol

t

Caps Nuts
And Washers

Cylinder Head Bol

t

Align

Bol

t

Cam Sprocke

t

Cap Nut And
Copper Washer

Arrow

Cam Chain

6. CYLINDER HEAD/VALVES

6-11

ACTIVE 50

Gaske

t

Left Side

7. CYLINDER/PISTON

7-0

ACTIVE 50

7

__________________________________________________________________________________

__________________________________________________________________________________

__________________________________________________________________________________

__________________________________________________________________________________

__________________________________________________________________________________

CYLINDER/PISTON

__________________________________________________________________________________

SCHEMATIC DRAWING-------------------------------------------------- 7- 1
SERVICE INFORMATION ------------------------------------------------ 7- 2
TROUBLESHOOTING----------------------------------------------------- 7- 2
CYLINDER REMOVAL --------------------------------------------------- 7- 3
PISTON REMOVAL -------------------------------------------------------- 7- 4
PISTON INSTALLATION ------------------------------------------------- 7- 6
CYLINDER INSTALLATION--------------------------------------------- 7- 6

7

7. CYLINDER/PISTON

7-1

ACTIVE 50

SCHEMATIC DRAWING

7. CYLINDER/PISTON

7-2

ACTIVE 50

SERVICE INFORMATION

GENERAL INSTRUCTIONS

• The cylinder and piston can be serviced with the engine installed in the frame.

• When installing the cylinder, use a new cylinder gasket and make sure that the dowel pins are

correctly installed.

• After disassembly, clean the removed parts and dry them with compressed air before inspection.

SPECIFICATIONS

Ite

m

Standard Limit (mm) Service Limit (mm)
I.D. ⎯ 52.4
Warpage

⎯

0.05

Cylindricity

⎯

0.05

True roundness

⎯

0.05

Ring-to-groove top

⎯ 0.12

clearance

Second

⎯ 0.12

top

0.1～0.25 0.5

Piston, Ring end gap Second

0.1～0.25 0.5

piston ring Oil side rail

0.1～0.25

0.5

Piston O.D.

55.58～55.95 51.6

Piston O.D. measuring position

5mm from bottom of

s

kir

t

5mm from bottom of skirt

. Piston-to-piston pin clearance

0.005～0.014 0.1

Piston pin hole I.D.

0.01～0.35 13.00

Piston pin O.D

12.994～13.000 12.944

Connecting rod small end I.D. bore

13.016～13.034 13.08

TROUBLESHOOTING

• When hard starting or poor performance at low speed occurs, check the crankcase breather for
white smoke. If white smoke is found, it means that the piston rings are worn, stuck or broken.

Compression too low or uneven
compression Excessive smoke from exhaust muffler

• Worn or damaged cylinder and piston rings • Worn or damaged piston rings

• Worn, stuck or broken piston rings • Worn or damaged cylinder and piston

Compression too high Abnormal noisy piston

• Excessive carbon build-up in combustion • Worn cylinder, piston and piston rings
chamber or on piston head • Worn piston pin hole and piston pin

• Incorrectly installed piston

Cylinde

r

7. CYLINDER/PISTON

7-3

ACTIVE 50

CYLINDER REMOVAL

Remove the cylinder head.
Remove the cam chain guide roller.
Remove the cylinder by removing the
cylinder bolt.
Remove all gasket material from the cylinder
surface.

Remove the gasket and dowel pins.

CYLINDER INSPECTION

Inspect the cylinder bore for wear or damage.
Measure the cylinder I.D. at three levels of
top, middle and bottom at 90° to the piston
pin (in both X and Y directions).

Service Limit:52.4mm repair or replace if

over

52.4mm repair or replace if below

Measure the cylinder-to-piston clearance.
Service Limit:0.35mm repair or replace if

over

The true roundness is the difference between
the values measured in X and Y directions.
The cylindricity (difference between the
values measured at the three levels) is subject
to the maximum value calculated.

Service Limits:
True Roundness: 0.05mm repair or replace

if over

Cylindricity: 0.05mm repair or replace if over

Gaske

t

Guide Roller Bol

t

Cylinder Bol

t

Guide Rolle

r

Dowel Pins

Middle

Botto

m

Top

7. CYLINDER/PISTON

7-4

ACTIVE 50

Inspect the top of the cylinder for warpage.

Service Limit: 0.05mm repair or replace if over

PISTON REMOVAL

Remove the piston pin clip.
Press the piston pin out of the piston.

Install the piston rings onto the piston and
measure the piston ring-to-groove clearance.

Service Limits:

Top: 0.12mm replace if over
2nd: 0.12mm replace if over

Remove the piston rings and insert each
piston ring into the cylinder bottom.

Measure the piston ring end gap.
Service Limit: 0.5mm replace if over

Place a clean shop towel in the crankcase
to keep the piston pin clip from falling
into the crankcase.

＊

Piston

Piston Pin

Clip

• Use the piston head to push each piston
ring into the cylinder.

＊

7. CYLINDER/PISTON

7-5

ACTIVE 50

Measure the piston O.D.

Service Limit: 51.6mm replace if below
Measure the piston-to-piston pin clearance.

Service Limit: 0.10mm replace if over

Measure the piston pin hole I.D.
Service Limit: 13.06mm replace if over

Measure the piston pin O.D.
Service Limit: 12.944mm replace if below

Measure the connecting rod small end I.D.
Service Limit: 13.016mm replace if over

• Take measurement at 5mm from the
bottom and 90° to the piston pin hole.

＊

7. CYLINDER/PISTON

7-6

ACTIVE 50

PISTON RING INSTALLATION

Install the piston rings onto the piston.
Apply engine oil to each piston ring.

Install the piston, piston pin and a new piston
pin clip.

CYLINDER INSTALLATION

Install the dowel pins and a new cylinder
gasket on the crankcase.

Second
Side Rail

Top

Second

Top

Side Rail

Oil Ring

• Position the piston “IN” mark on the

intake valve side.

• Place a clean shop towel in the

crankcase to keep the piston pin clip
from falling into the crankcase.

＊

• Be careful not to damage the piston and
piston rings during assembly.

• All rings should be installed with the
markings facing up.

• After installing the rings, they should
rotate freely without sticking.

• Stagger the ring end gaps as the figure
shown.

＊

“IN” Mark

Piston Pin Clip

Piston PinPiston

Dowel Pins

Gaske

t

7. CYLINDER/PISTON

7-7

ACTIVE 50

Coat the cylinder bore, piston and piston
rings with clean engine oil.
Carefully lower the cylinder over the piston
by compressing the piston rings.

Install the cam chain guide roller and tighten
the roller bolt.

Temporarily install the cylinder bolts.
Install the cylinder head (page 6-10).
Tighten the cylinder bolt to the specified

torque.
TORQUE: 0.6～0.9kg-m

Bol

t

• Be careful not to damage or break the
piston rings.

• The piston ring end gaps should not be
parallel with or at 90° to the piston pin.

＊

Roller Bol

t

Guide Rolle

r

8. ALTERNATOR/STARTER CLUTCH/

9. CAM CHAIN TENSIONER

8-0

ACTIVE 50

8

__________________________________________________________________________________

__________________________________________________________________________________

__________________________________________________________________________________

__________________________________________________________________________________

__________________________________________________________________________________

ALTERNATOR/STARTER CLUTCH/

CAM CHAIN TENSIONER

__________________________________________________________________________________

SERVICE INFORMATION------------------------------------------------ 8-2
TROUBLESHOOTING----------------------------------------------------- 8-2
ALTERNATOR REMOVAL ---------------------------------------------- 8-3
STARTER CLUTCH REMOVAL ---------------------------------------- 8-4
CAM CHAIN TRNSIONER ----------------------------------------------- 8-5
TENSIONER SPRING AND PUSH ROD ------------------------------- 8-5
STARTER CLUTCH INSTALLATION --------------------------------- 8-6

8

8. ALTERNATOR/STATER CLUTCH/
CAM CHAIN TENSIONER

8-1

ACTIVE 50

SCHEMATIC DRAWING

8. ALTERNATOR/STARTER CLUTCH/

9. CAM CHAIN TENSIONER

8-2

ACTIVE 50

SERVICE INFORMATION

GENERAL INSTRUCTIONS

• The starter motor, generator, left crankcase and starter clutch can be serviced in the frame.

• Do not install the starter clutch forcedly.

• Install the generator by aligning the groove in the flywheel with the key on the crankshaft.

• Install the starter motor reduction gear shaft by aligning the shaft pin with the shaft seat groove.

SPECIFICATIONS

Ite

m

Standard (mm

)

Service Limit (mm

)

Push rod O.D. 11.985～12.00 11.945
Driven sprocket O.D. 37.87～37.90 37.60
Driven sprocket I.D. 19.01～19.02 19.041
Tensioner spring free length 110～107 90

TORQUE VALUES

Flywheel lock nut 3.2～4.0kg-m

SPECIAL TOOLS

Flywheel holder E021
Flywheel puller E003

TROUBLESHOOTING

Hard starting and poor performance at high speed

• Improperly tightened flywheel lock bolt Starting noise

• Worn reduction gear

Starter clutch slips • Worn starter gear

• Worn starter clutch roller • Worn starter clutch roller

• Faulty starter clutch roller or spring • Faulty reduction gear shaft bearing

• Worn starter gear shaft O.D.

8. ALTERNATOR/STATER CLUTCH/
CAM CHAIN TENSIONER

8-3

ACTIVE 50

ALTERNATOR REMOVAL

Remove the four bolts.
Remove the left crankcase cover.

Remove the gasket and dowel pins.

Remove the flywheel nut and washer while
holding the flywheel with a flywheel holder.

Flywheel holder

Remove the flywheel using a flywheel puller
as shown.

Flywheel puller

Flywheel Holde

r

Dowel Pins

Fl

y

wheel Pulle

r

Gaske

t

Bolts

Special

Special

8. ALTERNATOR/STARTER CLUTCH/

9. CAM CHAIN TENSIONER

8-4

ACTIVE 50

Remove the clamp.
Remove the five bolts and alternator stator
base from the crankcase cover.

STARTER CLUTCH REMOVAL

REMOVAL

Drain the engine oil (page 3-3)
Remove the alternator (page 8-3)

Remove the stopper plate and chain sliders.
Remove the snap ring.
Remove the chain, starter drive sprocket and
driven sprocket as an assembly.

Remove the two screws, base plate and three
O-rings.

INSPECTION

Inspect the chain sliders for wear or damage.
Replace them if necessary.

Bolts

Clamp

Chain Sliders

Stator Base

• Do not disassemble the stator and pulse
generator coils.

＊

Snap Rin

g

Drive Sprocke

t

Stopper Plate

Chain Sliders

Driven Sprocke

t

Screws Base Plate

8. ALTERNATOR/STATER CLUTCH/
CAM CHAIN TENSIONER

8-5

ACTIVE 50

INSPECTION

Measure the driven sprocket O.D.
Service Limit:37.83mm replace if over

Measure the driven sprocket I.D.
Service Limit:19.06mm replace if over

Check the one-way clutch rollers, spring
caps and springs for wear or damage.

CAM CHAIN TENSIONER

REMOVAL

Drain the engine oil (page 3-3)
Remove the alternator (page 8-3)

Remove the starter clutch (page 8-4)
Remove the tensioner sealing bolt, washer,
spring and tensioner rod.
Remove the pivot bolt and cam chain
tensioner.

TENSIONER SPRING AND PUSH
ROD

INSPECTION

Measure the tensioner spring free length.
Service limit: 90mm

Sprin

g

Cam Chain Tensione

r

Sprin

g

Spring Cap

Rolle

r

Washer And Bol

t

Tensioner Rod

8. ALTERNATOR/STARTER CLUTCH/

9. CAM CHAIN TENSIONER

8-6

ACTIVE 50

Check the push rod valve for clogged
Check the push rod for wear or scraches.
Measure the push rod O.D.

Service limit: 11.945 mm

INSTALLATION

Install the cam chain tensioner and secure it
with the pivot bolt.

Install the tensioner rod, spring, sealing
washer bolt.

Tighten the tensioner sealing bolt.
TORUQE: 1.5～2.5 kg-m

Install the starter clutch and alternator (page
8-6)

STARTER CLUTCH
INSTALLATION

Install the new O-rings onto the left
crankcase and base plate,

Install the base plate, being careful not to
damage the O-ring.

Tighten the base plate screws.

Install the tensioner spring with its small

coil end up.

＊

Tensione

r

O-rings

TensionerRod

Spring

Sealing Washer And Bolt

Base Plate

One Way Valve

8. ALTERNATOR/STATER CLUTCH/
CAM CHAIN TENSIONER

8-7

ACTIVE 50

Install the chain, drive sprocket and driven
sprocket as an assembly.

Install the following components:

-snap ring.

-stopper plate.

-chain sliders.

Install the alternator stator base and secure it
with the two bolts.

Install the grommet into the grove of the left
crankcase cover.

Install the wire clamp.

Install the woodruff key on the crankshaft,
Wipe all oil lff the inside of the flywheel

amd crankshaft, and install the flywheel
aligning its groove with the woodruff key.

Install and tighten the flywheel nut while
holding the flywheel with a flywheel holder.

TORQUE: 3.2～4.0 kg-m

Flywheel Holder

Drive Sprocke

t

Chain

Snap Ring

Stopper Plate

Chain Sliders

Gromme

t

Clamp

Bolts

Stator Base

Nut

Flywheel Holde

r

Install the flywheel, turning it
counterclockwise.

＊

Special

8. ALTERNATOR/STARTER CLUTCH/

9. CAM CHAIN TENSIONER

8-8

ACTIVE 50

Install the dowel pins and a new gasket.

Install the left crankcase cover and tighten
the four bolts.

Torque: 0.8～1.2kg-m

Gaske

t

Dowel Pins

Bols

9. CLUTCH/GEAR SHIFT MECHANISM

9-0

ACTIVE 50

9

__________________________________________________________________________________

__________________________________________________________________________________

__________________________________________________________________________________

__________________________________________________________________________________

__________________________________________________________________________________

CLUTCH/GEAR SHIFT MECHANISM

__________________________________________________________________________________

SERVICE INFORMATION------------------------------------------------ 9 -2
TROUBLESHOOTING----------------------------------------------------- 9 -3
RIGHT CRANKCASE COVER REMOVAL --------------------------- 9 -4
CENTRIFUGAL CLUTCH/MANUAL CLUTCH REMOVAL ------ 9 -4
CENTRIFUGAL CLUTCH/MANUAL CLUTCH INSTALLATION 9 -8
GEAR SHIFT MECHANISM---------------------------------------------- 9-11
RIGHT CRANKCASE COVER INSTALLAION ---------------------- 9-12

9

9. CLUTCH/GEAR SHIFT MECHANISM

9-1

ACTIVE 50

9. CLUTCH/GEAR SHIFT MECHANISM

9-2

ACTIVE 50

SERVICE INFORMATION

GENERAL INSTRUCTIONS

• The clutch and gear shift mechanism can be serviced in the frame.

• Install the clutch plates in the same chamfer direction.

• Install the thrust washer with the chamfer facing up and the flat facing down.

SPECIFICATIONS mm

ITEM STANDARD SERVICE LIMIT
Clutch outer. I.D. 110mm 110.4mm
Driven gear outer.O.D 46.0mm 45.80mm
Gear primary drive.O.D. 34.25mm 34.15
Center clutch. O.D. 68.00mm 67.7mm

Guide clutch center.O.D 21.00 20.97~20.93
Spring clutch damper 11.3mm
Spring clutch 17.5mm

Spring clutch free 21mm
Disc A clutch friction

thickness

2.7~2.73mm 2.5~2.53

Centrifugal clutch

Disc B clutch friction
thickness

3.7~3.73mm 3.5~3.53mm

TORQUE VALUES

Centrifugal clutch lock nut 3.8～4.5kg-m
Manual clutch lock nut 3.8～4.5kg-m
Drum stopper bolt 0.8～1.2kg-m

SPECIAL TOOLS

Clutch holder E017
Lock nut wrench 18mm E010
Gear holder
Lock nut wrench 20mm E009
Flywheel holder E021

TROUBLESHOOTING

9. CLUTCH/GEAR SHIFT MECHANISM

9-3

ACTIVE 50

Faulty clutch operation can usually be corrected by adjusting the clutch.

Clutch slips when accelerating

• Faulty clutch lifter mechanism

• Discs worn

• Weak spring

• Incorrect clutch adjustment

Clutch will not disengage

• Faulty clutch lifter

• Incorrect clutch adjustment

• Plates warped

ATC creeps with engine idling

• Faulty centrifugal clutch

Clutch operation feels rough

• Rough manual clutch outer slots

• Worn or damaged centrifugal clutch shoes or drum

Gearshift pedal will not return

• Weak or broken gearshift spindle return spring

• Binding gearshift spindle

Hard to shift

• Gearshift spindle damaged

• Stopper plate and pin damaged

• Stopper plate bolt loosened

• Clutch adjustment incorrect

Transmission jumps out of gear

• Stopper arm damaged

• Stopper plate damaged

• Stopper plate bolt loosen

9. CLUTCH/GEAR SHIFT MECHANISM

9-4

ACTIVE 50

RIGHT CRANKCASE COVER
REMOVAL

Drain the engine oil (page 3-3).
Remove the kickstarter pedal.
Remove the right crankcase cover attaching
bolts and right crankcase cover.
Remove the dowel pins and gasket.

CLUTCH LIFTER
REMOVAL/INSPECTION

Remove the lock nut, and O-ring.
Remove the clutch adjusting bolt and clutch

lifter.
Check the removed parts for wear or damage

and replace them if necessary.

CENTRIFUGAL
CLUTCH/MANUAL CLUTCH
REMOVAL

REMOVEAL

Remove the clutch lifter lever and clutch
lifter cam.

Remove the four bolts, oil filter rotor cover
and gasket.

Remove the clutch lifter bearing.

O-Ring

Lifter Leve

r

Adjusting Bol

t

Rotor Cover And Gaske

t

Bolts

Nut

Clutch Lifte

r

Lifter Ca

m

Bolts

Bearing

Rotor Cover And Gaske

t

9. CLUTCH/GEAR SHIFT MECHANISM

9-5

ACTIVE 50

Install the clutch holder and secure it with
the bolts.

Remove the lock nut and plane washer using
a lock nut wrench.
Remove the clutch.

Clutch holder
Lock nut wrench

Remove the clutch square nut.
Remove the washer and clutch square nut
lock nuts.

Remove the clutch.

Remove the clutch circlip.
Remove the gear primarv driven.

Lock Nuts

Square Nu

t

Lock Nut Wrench

Clutch Holde

r

Special

Washe

r

Clutch

Circlip

9. CLUTCH/GEAR SHIFT MECHANISM

9-6

ACTIVE 50

Remove the follows:

- Gear primary drive.

-Guide clutch center.

- Washer

MANUAL CLUTCH DISASSEMBLY

Remove the set ring(101.5mm)

Remove the four bolts(5*10mm)

Washe

r

Guide Clutch Cente

r

Gear primary drive

Set Ring(101.5mm

)

Bolts(5*10mm

)

Plate Drive Center Clutch Driven Gear Oute

r

Set Ring

Plate A Clutch

Disk Clutch Friction

Plate A Clutch

9. CLUTCH/GEAR SHIFT MECHANISM

9-7

ACTIVE 50

Measure the O.D. of the crankshaft at the
primary drive gear.

SERVICE LIMIT: 17.00mm

INSPECTION CLUTCH GEAR O.D/I.D

Inspect the clutch outer groove for scratches
caused by the friction disks.
Measure the clutch outer I.D.

Service Limit: 110mm

Measure the driven gear outer O.D.
Service Limits: 46mm

Measure the gear primary drive O.D.

Service Limits:34.25 mm

Measure the center clutch O.D.

Service Limits: 68mm

Measure the center clutch O.D

Service Limits:21 mm

INSPECTION
CLUTCH TENSION SPRING

Measure each spring clutch damper.
Service Limit:11.3 mm

Measure each spring clutch.
Service Limit: 17.5mm
Measure each spring clutch free
Service Limit: 21mm
Replace the spring with a new one if it is

shorter than the service limit.

CLUTCH FRICTION DISK

Measure each disk B clutch friction
thickness.

Service Limit:3.7 mm
Measure each disk A clutch friction

thickness.
Service Limit:2.7 mm

crankshaft

Clutch Outer

Driven Gear
Outer

Gear Primary
Drive

Center Clutch Guide Clutch Center

Spring Clutch Damper Spring Clutch

Spring Clutch Free

Disk B Clutch Friction

Disk A Clutch Friction

9. CLUTCH/GEAR SHIFT MECHANISM

9-8

ACTIVE 50

CLUTCH A PLATE/ CLUTCH A PLATE

Measure each clutch plate bending using a
feeler gauge.

Service Limit: 0.20mm

CENTRIFUGAL
CLUTCH/MANUAL CLUTCH
INSTALLATION

MANUAL CLUTCH ASSEMBLY

Coat the clutch discs and plates with clean
engine oil.
Assemble the clutch plate drive, driven gear

outer

, center clutch, plate A clutch, disk clutch

friction, plate B clutch and set ring.

Install the clutch four bolts.
Install the four spring clutch damper
Install the clutch Set Ring.

INSTALLATION

Install the collapsible.
Install the guide clutch center

Outer Clutch

S

p

line Washe

r

Collapsible

Plate Drive Center Clutch Driven Gear Oute

r

Set Ring

Plate A Clutch

Disk Clutch Friction

Guide Clutch Cente

r

Plate B Clutch

Set Ring

Outer Clutch

Spring Clutch Damper

9. CLUTCH/GEAR SHIFT MECHANISM

9-9

ACTIVE 50

Install the clutch outer guide onto the main
shaft.
Install the washer over the crankshaft.

Install the clutch drum and manual clutch
assembly.

Install the washer with the “OUT SIDE”
mark facing out.

Install the plane washer and centrifugal
clutch lock nut.

Install the clutch holder and secure it with
two bolts.

Tighten the lock nut to the specified torque.
TORQUE: 3.8～4.5kg-m

Clutch holder
Lock nut wrench

Clutch Dru

m

“OUT SIDE” Mark

Lock Nut Wrench

Gear Holde

r

Washe

r

Guide Clutch Cente

r

Gear primary drive

Gear Primary Drive

r

Manual Clutch Assembly

Washe

r

WasherLock

Special

9. CLUTCH/GEAR SHIFT MECHANISM

9-10

ACTIVE 50

Install the oil filter rotor cover and a new
gasket.
Secure the oil filter rotor with the three bolts.

Install the clutch Bearing.

Install the clutch lifter bearing and clutch lifter
Cam.(page9-10-4)
Install the clutch lifter lever onto the
Gearshift spindle,aligning its punch mark with
The notch mark on the spindle.
Install the right crankcase cover(page9-12).

Install the clutch lift comp.
Install the through oil through and through oil.
Install the spring cam plate sid.e
Install the Retainer Clutch Bot.

Bearing 6000

Gaske

t

Cove

r

Clutch Lifter Ca

m

Punch Mark And Notch Mar

k

Clutch Lifter Leve

r

Clutch Lift Comp

Retainer Clutch Bot

Spring Cam Plate Side

Through Oil

Through Oil Through

9. CLUTCH/GEAR SHIFT MECHANISM

9-11

ACTIVE 50

GEAR SHIFT MECHANISM

Remove the cenrifugal clutch and manual
clutch (page 9-3)
Remove the warcher.
Remove the gear shift spindle and washer.
Remove the gear shift pedal.

Remove the bolt, drum stopper and spring.
Remove the gearshift stopper plate bolt and
the plate.

INSTALL

Install the pin in the holes.
Install the warcher
Install the stopper plate, aligning the holes in

the stopper plate with the dowel pin.
Tighten the stopper plate bolt security.

Install the gear shift cam stopper and spring.
Tighten the 6mm lock bolt.
Torque: 0.8~1.2kg-m

Gear Shift Spindle

Gearshift StopperPlate

Bol

t

Drum Stoppe

r

Bol

t

Spring

Stopper Plate

Dowel Pin Holes

Gear Shift Cam Stoppe

r

Spring

Drum stoppe

r

gear shift pedal

r

warche

r

Warche

r

Pin

9. CLUTCH/GEAR SHIFT MECHANISM

9-12

ACTIVE 50

Install the gear shift spindle and washer.
During installation, make sure that the return

spring aligns with the crankcase tab.

RIGHT CRANKCASE COVER
INSTALLATION

Install the new O-ring and lock nut.

Install the dowel pin and a new gasket.

Install the right crankcase cover and tighten
the cover bolts.

Install the kickstarter pedal.
Adjust the clutch (page 2-8).

Gear Shift Spindle

Spring

Adjusting Bol

t

Lock Nu

t

O-ring

Dowel Pins

Gaske

t

Bolts