Service Manual
Holtvej 8-10, Høruphav, 6470 Sydals
Telefon: +45 73 15 11 00
Fax: +45 73 15 11 01
info@scanmi.dk · www.scanmi.dk
CVR: 27 73 31 07
www.genericmotor.dk
Juli 2011
ONYX
50
ONYX
Service Manual
Generic Motor GmbH
- 1 -
Contents
Contents................................................................................................................................................ - 1 -
Preface.................................................................................................................................................. - 7 -
Preparing documents....................................................................................................................... - 8 -
Inspection/Adjustment................................................................................................................... - 38 -
Inspection and maintenance of electrical system...................................................................................... - 53 -
1. Battery/charging system.................................................................................................................... - 55 -
1.1 Preparing documents ............................................................................................................... - 55 -
1.2 Failure diagnosis ..................................................................................................................... - 56 -
1.3 Battery ................................................................................................................................... - 57 -
1.4 Charging system...................................................................................................................... - 58 -
1.5 Rectifier ................................................................................................................................. - 59 -
1.6 Magnetor charging coil ............................................................................................................ - 60 -
1.7 Replacement of magnetor......................................................................................................... - 61 -
2. Ignition system................................................................................................................................. - 64 -
2.1 Preparing documents ............................................................................................................... - 64 -
2.2 Failure diagnosis ..................................................................................................................... - 65 -
2.3 Checking the ignition system.................................................................................................... - 66 -
2.4 CDI Group.............................................................................................................................. - 68 -
2.5 Ignition coil ............................................................................................................................ - 69 -
2.6 Trigger ................................................................................................................................... - 70 -
- 2 -
3. Activation system ............................................................................................................................. - 72 -
3.1 Preparing documents ............................................................................................................... - 72 -
3.2 Failure diagnosis ..................................................................................................................... - 73 -
3.3 Starting motor ......................................................................................................................... - 73 -
3.4 Starting relay .......................................................................................................................... - 75 -
4. Bulbs/Switches/Meters...................................................................................................................... - 79 -
4.1 Preparing documents ............................................................................................................... - 79 -
4.2 Failure diagnosis ..................................................................................................................... - 79 -
4.3 Headlight bulb replacement...................................................................................................... - 79 -
4.4 Front turn signal lamp bulb replacement .................................................................................... - 80 -
4.5 Taillight/Rear turn signal lamp replacement................................................................................ - 80 -
4.6 Meters.................................................................................................................................... - 81 -
4.7 Main switches......................................................................................................................... - 81 -
4.8 Speakers................................................................................................................................. - 81 -
4.9 Combined switch..................................................................................................................... - 82 -
Examination and maintenance of chassis................................................................................................ - 83 -
5. Brake .............................................................................................................................................. - 86 -
5.1 Maintenance instruction ........................................................................................................... - 86 -
5.2 Failure Diagnosis .................................................................................................................... - 87 -
5.3 Front fluid brake...................................................................................................................... - 87 -
5. 4 Rear drum brake..................................................................................................................... - 89 -
6. Body panel ...................................................................................................................................... - 93 -
- 3 -
7.Front wheel/front suspension.............................................................................................................. - 97 -
7.1 Preparation documents............................................................................................................. - 97 -
7.2 Failure diagnosis ..................................................................................................................... - 98 -
7.3 Front wheel............................................................................................................................. - 98 -
7.4 Steering handle ..................................................................................................................... - 100 -
7.5 Front fork ............................................................................................................................. - 101 -
8.Rearwheel/rear suspension ............................................................................................................... - 106 -
8.1 Preparing documents ............................................................................................................. - 106 -
8.2 Failure diagnosis ................................................................................................................... - 106 -
8.3 Rear wheel............................................................................................................................ - 107 -
8.4 Rear shock absorber............................................................................................................... - 108 -
9.Fuel tank/seat.................................................................................................................................. - 114 -
9.1 Preparation documents........................................................................................................... - 114 -
9.2 Failure diagnosis ................................................................................................................... - 114 -
9.3 Fuel tank/seat........................................................................................................................ - 115 -
10.Removal / installation of motor....................................................................................................... - 117 -
10.1 Preparation documents ......................................................................................................... - 117 -
10.2 Failure diagnosis ................................................................................................................. - 117 -
10.3 Removal of motor................................................................................................................ - 118 -
10.4 Installation of motor............................................................................................................. - 119 -
Inspection and maintenance of motor ................................................................................................... - 120 -
11.Lubricaiton system ........................................................................................................................ - 122 -
- 4 -
11.1 Preparation documents ......................................................................................................... - 122 -
11.2 Failure diagnosis..................................................................................................................- 122 -
11.3 Machine oil pump................................................................................................................ - 123 -
12.Carburetor .................................................................................................................................... - 127 -
12.1 Preparation documents ......................................................................................................... - 127 -
12.2 Failure diagnosis ................................................................................................................. - 128 -
12.3 Removal of carburetor.......................................................................................................... - 128 -
12.4 Installation and adjustment ................................................................................................... - 130 -
13.Cylinder cap ................................................................................................................................. - 133 -
13.1 Preparation documents ......................................................................................................... - 133 -
13.2 Failure diagnosis ................................................................................................................. - 133 -
13.3 Cylinder cap........................................................................................................................ - 133 -
13.4 Cylinder cap inspection........................................................................................................ - 134 -
13.5 Installation of cylinder cap.................................................................................................... - 134 -
14.Cylinder body and piston................................................................................................................ - 137 -
14.1 Preparation documents ......................................................................................................... - 137 -
14.2 Failure diagnosis ................................................................................................................. - 138 -
14.3 Cylinder body ..................................................................................................................... - 138 -
14.4 Piston ................................................................................................................................. - 139 -
14.5 Installation of piston ............................................................................................................ - 142 -
15.Driving /clutch/driven wheel/foot driving device .............................................................................. - 146 -
15.1 Preparation documents ......................................................................................................... - 146 -
- 5 -
15.2 Failure diagnosis ................................................................................................................. - 146 -
15.3 Left crankcase cover ............................................................................................................ - 147 -
15.4 Driving disc ........................................................................................................................ - 147 -
15.5 Clutch/driven wheel............................................................................................................. - 149 -
15.6 Detach clutch and driven wheel............................................................................................. - 151 -
15.7 Install ................................................................................................................................. - 155 -
15.8 Foot starting device.............................................................................................................. - 155 -
16.1 Preparation documents ......................................................................................................... - 158 -
16.2 Failure diagnosis ................................................................................................................. - 158 -
16.3 Gear box............................................................................................................................. - 158 -
16.4 Installation.......................................................................................................................... - 159 -
17．Crankcase .................................................................................................................................. - 161 -
17.1 Preparation documents ......................................................................................................... - 161 -
17.2 Failure diagnosis ................................................................................................................. - 161 -
17.3 Crankcase ........................................................................................................................... - 162 -
17.4 Installation.......................................................................................................................... - 164 -
Inspection and maintenance of exhaust gas discharge control system....................................................... - 164 -
18.Exhaust gas discharge control system .............................................................................................. - 166 -
18.1 Exhaust gas discharge control system reconizance................................................................... - 166 -
18.2 Regular maintenance notes ................................................................................................... - 166 -
18.3 Mechanic function of exhaust gas discharge control system ..................................................... - 167 -
18.4 Catalytic transfer system ...................................................................................................... - 167 -
- 6 -
18.5 Solution for idle discharge value exceeding defined value (two-stroke) ..................................... - 169 -
- 7 -
Preface
This is maintenance manual for QJ50QT-22D.
Preparing Documents include all necessary instructions and statements. Please
carefully read this manual before operation.
Inspection & Adjustment states how to check and adjust your motorcycle. All
safety rules and maintenance regulations shall be carried out from the beginning of
periodic inspection.
Except for chapter one, the rest chapters explain the disassembly/ assembly/
inspection of engine, entire motorcycle and electrical parts.
Breakdown drawing, systematic drawing, failure analysis and statement are
contained at the first part of each chapter.
Please note that photos, pictures or instructions are for your reference only. The
actual object may differ from these mentioned here. We will not make notification for
any discrepancy.
Generic Motor GmbH
- 8 -
Preparing documents
General safety Maintenance rules
Specification table Failure diagnosis
General Safety
Carbon monoxide
Engine shall be started in a ventilated place, not in a closed area.
Note
Exhaust gas contains poisonous carbon monoxide, which may cause unconsciousness or even death of human
being.
Start engine in an open place. The exhaust cleaning system shall be adopted if engine is started in a closed area.
Petrol
Ventilated place is required for working. Fire is strictly forbidden in work place or where petroleum is stored.
- 9 -
Maintenance Rules
Metric tools are preferable for the maintenance of this motorcycle. Improper tools may cause damage.
Clean up the surface of parts or assembly parts before removing or opening the shield for maintenance, which can
prevent dirt from falling into the engine, chassis or braking system.
Wash parts and dry with compressed air machine after
disassembly and before measurement of attrition value.
Solvent or oil can easily damage aging rubber articles. Check
rubber before reassembly and replace rubber if necessary.
When releasing assembly parts, please start from outside to inside.
Small assembly parts shall be loosened first.
Complex assembly parts, such as gear box, shall be stored in
proper order for facilitating installation in the future.
Please specially note the important connections before
disassembly. Replace parts which will not be in use before
disassembly.
Sheath
- 10 -
Bolts and screws with different length will be separately used for
assembly parts and shields, and they shall be correctly mounted.
Insert a bolt into a hole to check whether it is proper if you are
confused.
Fill the groove with grease before mounting an oil seal. Check
whether the oil seal is smooth or damaged during assembly.
When installing a hosepipe (fuel, vacuum or cooling agent),
insert its end into the bottom of the connector so that the hose clip
can properly fix the connector. Rubber or plastic dirt-proof boot
shall be mounted according to the original design.
During dismantling ball bearing, one or two (inside & outside)
bearing rollers shall be supported by tools. Ball bearings may be
damaged and have to be replaced if only one roller (either inside
or outside) is imposed with force.
Groove
Clip
Connector
Bearings will be broken under either occasion as
mentioned.
- 11 -
Loose cables threaten electrical safety. Check each cable after they are all clamped to ensure the electrical safety;
Wire clamps are not allowed to bend towards welding point;
Bind cables at the designated place;
Do not deploy cables at the end of frame or at sharp point;
Do not deploy cables at the end of bolts or screws;
Cable deployment shall be far from heat source and where
cables may be clamped during moving;
Cables along the handlebar shall be neither too tight nor too
loose, and do not interface with any neighboring parts at
steering positions;
Cables shall be properly deployed without twist or knot;
Check whether the connector jacket is damaged and whether
the connector is over-stretched before mounting connectors;
Adopt adhesive tape or hosepipe to protect cables if they are
positioned at sharp point or corner;
Bind cables with tape after repairing;
Control cables shall not be bent or twisted. Clumsy operation
may be caused in light of damaged control cables.
- 12 -
Identification of Motorcycle
1. The identification number of motorcycle frame is
marked at : *LBBB4900?8B?????*. The 9
th
digital,
10 digital and 11
th
digital respectively indicate
inspection code, year and supplier code. There are
17-digital in total. The frame sign is nailed at . See
Fig. 1-1.
Fig. 1-1
2. The serial number of engine is printed on the shell of
crankcase of engine and shall be in the format of
KW1E40QMB-4*□□□□□□□□*. Please see fig. 1-2.
Fig. 1-2
Significant Notes
1. Please apply valid Generic parts and accessories. Any part or accessory not in accordance with the design
specification of Generic Company may cause damage to engine.
2. Only metric tools are valid for maintenance and repair. Metric screws, bolts and nuts can not be exchanged with
imperial fasteners.
3. New gaskets, O-rings, cotter pins and locking pieces shall be applied for re-assembly.
4. Bolts with large diameter or positioned inside shall be fastened first and then diagonally screw down until
reaching required torque, otherwise there is special instruction.
5. Wash disassembled parts with cleanser. Lubricate all sliding surface before assembly.
6. Check whether all the parts and accessories are correctly mounted and operated after assembly.
7. Clean and remove oil before measurement. Add recommended lubricant to the lubricating areas during
assembly.
8. Apply lubricant to the surface of engine and driving system if they are dismantled for long-term storage, which
can prevent rust and dirt.
- 13 -
Special Tools
Special tools refer to tools which are specially designed for assembling or disassembling some motorcycle
parts on special positions. Applicable special tools are necessary for precise adjustment and installation. With
them, parts and accessories can be mounted safely, reliably and rapidly, which improves efficiency and saves
energy.
1．Tools for repairing engine
Special tools are required for properly disassembling/assembling some engine parts.
List and drawing (1-1, 1-2) of special tools for disassembling/assembling engine parts are as follows:
Table 1-1
Name Remark
Special socket spanner
Clutch clamp holder
Flywheel puller
Feeler gauge
Bearing disassembly tools
Bearing assembly tools
Oil seal remover
Handle for dismantling tools
Piston pin pulling device
Piston pin pliers
Socket spanner for spark plug
Clutch thickness measuring device
Cylinder diameter measuring device
Dial indicato
Used for assembling/disassembling bolts for flywheels, Fig. 1-3
Fig. 1-4
Fig. 1-5
Fig. 1-6
Fig. 1-7
Fig. 1-8
Fig. 1-9
Fig. 1-10
Fig. 1-11
Fig. 1-12
Fig. 1-13
Fig. 1-14
Fig. 1-15
Measuring the inner diameter of piston pin, Fig. 1-16
Table 1-2 (continued)
Fig. 1-3 Fig. 1-4
- 14 -
Fig. 1-5 Fig. 1-6
Fig. 1-7 Fig. 1-8
Fig. 1-9 Fig. 1-10
handle
Fig. 1-11 Fig. 1-12
Thickness gauge
(feeler gauge)
- 15 -
pliers piston
Fig. 1-13 Fig. 1-14
Fig. 1-15 Fig. 1-16
2．Tools for repairing chassis
List and drawing (1-17, 1-18) of ordinary tools and special tools for disassembling/assembling chassis parts are
as follows:
Tabl e 1-17
Name Remark
Torque spanner
Inner hexagon spanner
Socket spanner
Dial indicator
Magnetic rack, V-block
Micrometer
Vernier calipers
Circlip pliers
Screwdriver with striking cap
Tool for assembling oil seal of front fork
Tool for hammering seal of front fork
Steering nut spanner
Fig. 1-19
Fig. 1-20
Fig. 1-21
Fig. 1-22
Fig. 1-23
Fig. 1-24
Fig. 1-25
Fig. 1-26
Fig. 1-27
Fig. 1-28
Fig. 1-29
Fig. 1-30
(1) Ordinary tools for repairing chassis
Table 1-18 (continued)
- 16 -
Fig. 1-19 Fig. 1-20
Fig. 1-21 Fig. 1-22
Fig. 1-23 Fig. 1-24
Fig. 1-25 Fig. 1-26
Fig. 1-27 Fig. 1-28
(2) Special tools for repairing chassis: tool for hammering seal of front fork
1. socket head 2. crank handle 3. ratchet spanner
4. connecting rod
- 17 -
Fig. 1-29
(3) Steering nut spanner
Fig. 1-30
3．Tools for electric parts
List and drawings (1-31, 1-32) of special tools for testing electric parts are as follows:
Tabl e 1-31
Name Remark
Multimeter
Ignition tester
Fig. 1-33
Fig. 1-34
Table 1-32 (continued)
Fig. 1-33
Fig. 1-34
- 18 -
Specification (QJ50QT-22D)
Model QJ50QT-22D
Engine type
QJ1E40QMB-4
Length mm
1940
Fuel type
Unleaded petrol
(92/95)
Width mm
730
No. of
cylinder
1
Height mm
1110
ID × stroke
40×39.2
Wheelbase mm
1305
Tota l
displacement
49.2CC
Forward
shaft
39
Startup
Electric/kick
Backshaft
62
Cooling
Air cooling
Wei ght kg
(Curb weight)
Tot a l
102
Front outer
tyre
80/80-16
Lubrication
Separate
lubrication
Front rim 16 X 1 .6
Rear outer
tyre
90/80-16
Air filter
AF-B45
Tyre
Size
Rear rim 16 X 1 .8 5
Capacity of
gasoline
tank
5.5 L±0.2L
Clutch
Dry centrifugal
clutch
Variable speed
gear
Stepless
Engine
Carburetor
type
PZ19JB-2K
T
ransmissio
n
gear
Transmission
Belt transmission
Idle speed
1900±100rpm/min
Max. torque
4.36N.m/5250rpm
Battery
capacity
12V-4AH
Max. Hp
2.60kW/6500rpm
Electromagnetic
motor capacity
90W/5000rpm
Compression
ratio
6.9：1
Spark plug
BR8HSA（ NGK）
Performance
Max. speed
45km/h
Clearance of
spark plug
0.6-0.7mm
Electric
devices
Ignition
CDI
Braking
Dia. of fluid
brake disc,
front wheel
φ220mm
- 19 -
system
I.D. of brake
drum, rear
wheel
φ140mm
QJ50QT-22D
- 20 -
N Y
N
Failure Diagnosis
Diagnosis on failure or difficulty in starting engine
F
ailure or difficulty in starting engine
Check ignition system
Remove the spark plug and check whether there is
carbon fouling between electrode.
Sparkover test for spark plug Eliminate carbon fouling
Weak spark or no spark between electrode Large blue or bluish purple spark between electrode
Screw off spark plug cap and conduct
sparkover test for high tension line
Check whether ignition is timely conducted with
an ignition timing light
Large blue spark Weak spark or no spark
Check whether spark plug and cap are in
good condition
Check power
supply for
ignition
Check whethe
r
short circuit o
r
open circui
t
occurs to
ignition coil
Check whethe
r
short circuit o
r
open circuit occurs
inside the ignitio
n
system
Check whether
CDI ignition
device is in
good condition
Check the compressio
n
p
ressure of cylinde
r
with pressure gauge
Check
whether there
is gasoline in
the fuel tank
Normal
compression
pressure
Insufficient
compression
pressure
Add
gasonline
N
on-contact ignition system
for electromagnetic motor
1. Check whether short
circuit or open circuit
occurs to ignition coil
2. Check whether short
circuit or open circuit
occurs to trigger coil
1. Check whether CDI
ignition device is in good
condition
2. Check whether flywheels
and trigger coil are
loosened
Screw off the bolt of
carburetor and
check whether there
is gasoline in the
overflow tube
- 21 -
Y N
Moist electrode of spark plug Dry electrode of spark plug
Check whether there is oil
spillover in the carburetor
Drop a little gasoline into the cylinder for trial startup
1. Check whether the
float needle valve and
the valve seat are
firmly closed
2. Check whether the
conical surface of float
needle valve is abrasive
as steps
3. Check whether the float
needle valve is broken
4. Check whether the float
needle valve is too low
Check whether air
filter is blocked
Flameout shortly
after startup
Continue to work
after startup
The carburetor is blocked
inside or the float is too
high
Startup device of
carburetor (startup &
enrichment system)
is at fault
Remove spark
plug and check it
- 22 -
Y N
Y N
Y N
N Y
Y N
Diagnosis on engine overheating
Engine overheating
Check whether operation is correct
1. Check whether gasoline grade is
im
p
roper or stored for a long
time
2. Check whether the engine works
at high speed for a long time or
with overload during driving
Check cooling system
Air-cooled engine
Check whether heat sink is spotted or there
is too much oil stain
Clean
Check whether cooling fan or air
director is damaged (forcedly
air-cooled engine)
Inspection & solution
Check whether ignition is
timely conducted with a
n
ignition timing light
1. Check whether
CDI ignition
device is in good
condition
2. Check whether
flywheels and
trigger coil are
loosened
Check whether clutch is slipping
Slipping clutch
Solution to
slipping clutch
- 23 -
Remove the spark plug; check the
colors of spark plug insulators
and judge the proportion of
mixed combustible gas based on
abnormity
The spark plug insulators are black;
the exhaust muffler emits black
smoke or causes backfire if the
engine works at low speed;
b
ad
acceleration property; instable idle
speed; flameout probability; it
works normall
y
at high speed.
The spark plug insulators are brown
The spark plug insulators are
white; the engine may intermit
during acceleration; the
carburetor generates backfire;
insufficient power of engine
Mixed combustible gas
is too dense.
1. Check whether the air filter is
blocked.
2. Check whether the startup device
for carburetor (startup & enrichment
system) works normally.
3. Check whether the float needle
valve is too low.
Normal combustible gas mixture
Check whether the cylinder
outlet or the exhaust muffler
is blocked due to accumulated
carbon fouling.
Check the
lubrication system
Mixed combustible
gas is diluted.
1. Check whether fuel
cock works
normally.
2. Check whether the
float needle valve is
too high.
3. Check whether the
measuring jets and
drill ways in the
carburetor are
b
locked.
- 24 -
Y N
Diagnosis on power shortage of engine
Power shortage of engine
Raise the main kickstand and lift wheels; rotate
wheels with hands
Flexible rotating
of wheels
Inflexible rotating of
wheels
Check tyre
pressure
1. Check whether there is
braking drag.
2. Check whether wheel bearing
is excessively abraded or
damaged.
3. Check whether the spacer
sleeve of hub is missed or too
short.
Low pressure
Normal
pressure
Check whether air leakage
occurs to tyre valve and whether
tyre is pierced or broken
Remove the spark plug and block the threaded
hole with finger; press the startup button or
step on the kick-start lever
Touch with your fingers and you can
feel fierce air rushing out with puffing
sound.
Touch with your fingers and you can not
feel fierce air rushing out.
Normal compression
pressure of cylinder
Insufficient compression
pressure of cylinder
1. Check whether there is air
leakage in all outer joints of
engine.
2. Check whether air supply is
timely conducted.
3. Check whether clearing
between valves is too small.
4. Check whether valve and valve
seat are well sealed.
5. Check whether piston ring is
ruptured, blocked in the groove
or lacks elasticity.
6. Check the abrasion of piston
ring and cylinder.
Start the engine and slow accelerate;
observe the rotation speed change of
engine.
The rotation speed of engine rises as it
slowly accelerates.
The rotation speed of engine does not rise
as it slowly accelerates.
Check whether ignition is timely
conducted with an ignition timing
light
1. Check whether the clutch is slipping.
2. Check whether the driving belt is
excessively abraded.
3. Check whether the centrifugal roller of
driving pulley is excessively abraded.
4. Check whether the conical surface of
driving wheels and friction wheels is
excessively abraded or abraded as
groove.
5. Check whether the conical surface of
driven wheels and moving driven wheels
is excessively abraded or abraded as
groove.
6. Check whether the roll-away nest on the
inner surface of friction wheels is
excessively abraded or pressed into be
concave.
1. Check whether the fuel supply system
works normally.
2. Check whether the carburetor, air filter
and exhaust muffler are blocked.
3. Check whether the vacuum diaphragm
of plunger valve of carburetor is
cracked or broken.
4. Check whether the height of
carburetor float is proper.
1. Check whether CDI
ignition device is in
good condition
2. Check whether
flywheels and trigger
coil are loosened
- 25 -
Y N Y N
N Y
Y N
Y
N
Diagnosis on abnormal idle speed of engine
Abnormal idle speed of engine
High idle speed No idle speed Unstable idle speed
Check compression
pressure of cylinder
Check whether the carburetor
valve is completely closed with
your hand.
Check whether ignition is
timely conducted with an
ignition timing light
Insufficient
compression pressure
Normal compression
pressure
1. Check whether there
is air leakage in all
outer joints of engine.
2. Check whether air
supply is timely
conducted.
3. Check whether
clearing between
valves is too small.
4. Check whether valve
and valve seat are well
sealed.
5. Check whether
p
iston ring is ruptured,
b
locked in the groove
or lacks elasticity.
6. Check the abrasion
of piston ring and
cylinder.
Adjust the idle speed of
carburetor.
Check
whether idle
jet is too big.
Check whether the
steel wire rope of
accelerator control
cable is flexible
when pulling and
whether the
throttle valve
spring is too soft.
Check
whether
the
electrode
clearing
of spark
p
lug is
too small.
1. Check whether
CDI ignition
device is in
good condition
2. Check whether
flywheels and
trigger coil are
loosened
Idle speed after
adjustment
No idle speed after
adjustment
The air adjusting
screws or the
adjusting screws
for throttle valve
are improperly
adjusted.
Check whether the
carburetor idle jet, idle
fuel way and air path is
blocked.
Clean and
clear
Check whether carburetor float is
placed at high position.
Adjust the float
height to standard
value.
1. Check whether the heat insulator of carburetor
is cracked.
2. Check whether the fixing nuts of carburetor
are loosened.
3. Check whether the vacuum tube of fuel cock
is broken.
4. Check whether air leakage occurs to reed
valve.
Adjust the
electrode
clearing.
Check the proportion
of mixed
combustible gas.
- 26 -
Y N
Y N
Y N
Y N
Diagnosis on excessive fuel consumption of engine
Check and adjust the carburetor.
Excessive fuel
consumption of engine
Check whether operation is
correct
Raise the main kickstand and rotate
wheels with hands
1. Check whether motorcycle runs
with overload or not at
economical speed or with low
gear.
2. Check whether petrol grade is
proper.
Inflexible rotating of
wheels
Flexible rotating
of wheels
1. Check whether
there is braking
drag.
2. Check whether
wheel bearing is
seriously abraded or
damaged.
3. Check whether the
spacer sleeve of hub
is missed or too
short.
Check tyre
pressure
Low pressure
Normal
pressure
Inflate as required
Check whether oil leakage occurs
in fuel box, fuel cock, oil pipe
and carburetor.
Solve problems based on
actual situation
Check the proportion of
mixed combustible gas.
Normal combustible gas mixture
Mixed combustible
g
as is too dense.
Mixed combustible
gas is diluted.
Check whether the idle speed
of engine is too high.
1. Check whether the air filter
is blocked.
2. Check whether the
carburetor float is too low.
3. Check whether the main
measuring jet of carburetor
is too big.
1. Check whether the
carburetor is blocked
inside.
2. Check whether the
carburetor float is too
high.
Check and adjust the
carburetor.
Check whether ignition is
timely conducted with an
ignition timing light
Check whether the
driving belt of clutch is
slipping.
Check the ignition
system.
- 27 -
N Y
N Y
N Y
Y N
Y N
N Y
Diagnosis on clutch slipping
Diagnosis on transmission gear skip shift
Clutch slipping
Automatic shoe-type centrifugal & dry
clutch is slipping.
Check whether the
shoe-type friction plate is
excessively abraded.
Replace the whole set of
clutch shoe blocks
Clean and
remove oil stain
Check whether the contact
surface between shoe-type
friction plate and friction
disc is beyond 70%.
Check whether the contact surface between
shoe-type friction plate and friction disc is
excessively abraded.
修理或更换
Check whether the shoe-type friction plate
is spotted with oil stain.
Transmission gear
skip shift
Check whether the spring of positioning
wheels is ruptured or lacks elasticity.
Replacement
Disassemble crankcase and check whether the depth in
engaging for each gear is in accordance with requirements.
Proper depth in
engaging
Insufficient depth in
engaging
Check whether the engaging end of the cam claw on the engaged gear
face is abraded to be conical or largely circular, and whether the groove
on the corresponding gear face is abraded to be trumpet-shaped.
Check whether the shift fork is
excessively abraded or deformed.
Replace gear
Check whether the spline teeth of
main shaft/countershaft and the
spline groove in the clash gear is
excessively abraded.
Replace shift
fork
1. Check whether shift fork hole and shaft
are abraded.
2. Check whether the clearing between shift
fork pin/gear shift shaft and cam groove
is too big.
3. Check whether the installation of
transmission is correct.
Repair or replace clutch shoe
blocks.
- 28 -
N Y
Y N
N Y
Diagnosis on malfunction of hydraulic disc brake
Diagnosis on malfunction of drum brake
Malfunction of hydraulic
disc brake
Check the level of brake fluid inside the
brake fluid reservoir.
The level of brake fluid is below the
lower limit of the reservoir.
The level of brake fluid is beyond the
lower limit of the reservoir.
Add brake fluid until
it is beyond the
lower limit; check
whether there is oil
leakage in brake
caliper, brake hose
and hose coupling.
Do you have "sponge" feeling
when operating brake lever?
There is air left in
the oil passage of
brake system.
Check whether the abrasion of brake friction
p
late reaches limit mark and whether the
brake disc is excessively abraded.
Replace brake friction plate
and brake disc.
1. Check whether the piston surface of master brake pump and the wall of oil tank are
excessively abraded or damaged.
2. Check whether the piston cup of master brake pump is damaged, cracked or aged.
3. Check whether the seal of brake caliper is damaged, cracked or aged.
4. Check whether the piston surface of brake caliper and the wall of oil tank are
excessively abraded or damaged.
Malfunction of drum
brake
Check whether the free stroke of brake lever is within
10mm ~ 20mm or whether the free stroke of brake pedal is
within 20mm ~ 30mm.
Readjustment
Separate the brake arm and the steel wire rope of brake control cable; check
the brake arm with hands.
The brake arm works
flexibly but you can
feel resistance when
griping the lever.
The brake
arm works
inflexibly.
The indication arrow on the
b
rake cam points to or beyond
the sign “▽” on the brake hub
cover.
The indication arrow on the brake cam
does not align with the sign “▽” on the
brake hub cover.
The steel wire rope
of brake control
cable is inflexible
when pulling.
1. Check whether the curved surface of
brake cam is excessively abraded.
2. Check whether the friction plate of brake
shoe is excessively abraded.
3. Check whether the inner diameter of
brake hub is
ex
cessively
abraded.
The moving
p
art of brake
cam is rusted or
b
locked by
something.
1. Check whether the friction surface of
brake shoe is spotted with oil stain.
2. Check whether the contact surface of
the friction plate of brake shoe and the
brake hub is less than 70%.
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