KAYO MOTOR TD125 User manual

KAYO MOTO
TD125
SERVICE MANUAL
www.kayomoto.com

This service manual is edited by KAYO.
Please do not modify the content without authorization.
Manufacturer has the right to improve and update the model’s structure and spare parts without notice.
The model in the image may be different from the real model.
PREFACE
Thank you for choosing the 21 TD125 of KAYO MOTO as your choice for off-road recreation. I believe you will
not be disappointed with this choice.
This manual is designed to help you better use our products. This manual describes in detail the maintenance and
adjustment procedures, disassembly and assembly essentials, inspection and maintenance points, troubleshooting
methods and maintenance technical data of TD125, with detailed graphic data to guide the operation.
Please read this manual carefully and carry out maintenance according to the standard operation techniques, which
can effectively prolong the service life of each component, improve the engine performance and the reliability of

the vehicle.
For the sake of technological development, KAYO reserves the right to modify the construction, equipment and
parts of the motorcycle without prior notice. Due to the different regulations and requirements in different markets,
we have made appropriate adjustments to the models, so the images in the manual may be different from the
standard motorcycle. In addition, if you have any questions, please go to our official website
www.kayomoto.com and contact our service staff. We must accept with humility.
The contents of this manual are subject to change without prior notice due to vehicle improvement. The actual state
of the vehicle shall prevail during maintenance.
ZHEJIANG KAYO MOTOR CO., LTD.
ENGINEERING OFFICE
AUGUST. 2021
Content
Meaning of Symbols and Technical terms…………………………………...............…………………………8
Suggestions for Daily Use……………………………………………………………................………………9
Appearance………………… ……10
21 TD125 Parts and Position.....……………………………………………………………..…………………10
VIN and Engine Number……………………………………………..………………………...............………12
VIN Number…………………...……………………………………………………………………….………12
Engine number………………………………………………………………………………………….………12
Specification………………………………………………………………………………….................………13
21 TD125 Size and Weight Specification …………………………………..…………………………..………13
Manipulation……………………………………………………….................…………………………………14
Front disc brake……..............…........................………………………………...………………………………14
Throttle…… ..……………………………………………………………………...……………………………14
Ignition………….………………………………………………………………….....…………………………14
Stall………………………....……………………….…………………………………...………………………15
Fuel tank switch…………………………….…….……………………………………….......…………………15
Gear shifting…………………………...........….……….……………………………………......………………15
Rear disc brake….…………..………………….………..........…………………………………………………16
Parking stand…………………………………................….....…………………………………………………16

Notes before Use………………………………….………..........................……………………………………17
Suggestions for first-time users…...….………….......................………………….……………………………17
Running-in process………....…………………….……………......……………………………………………17
Riding Guide…...……………………………….………………….................…………………………………18
Checking items before riding……….......…………………………………….........……………………………18
Notes when ignition………………………………………........……………………......………………………18
Notes when starting…………….....………...…………………………………………….......…………………18
Notes when cornering………....................……………………………………………………........……………19
Notes when acceleration…………….......................……………………………………………….........………19
Notes when gear shifting……..........….........……………………………………………………………………19
Notes when braking…………...................…........………………………………………………………………19
Notes when parking…………….......................…........…………………………………………………………19
Maintenance Periodic Table..............................................................……………………………………………20
Suspension system setup…………….........................................…...................…………………………………21
Check the compression and rebound of the motorcycle when riding……............................................…………21
Measure distance from center of rear wheel to rear fender in suspension...…..........................…………………21
Measure distance from center of rear wheel to rear fender under no load.................................…………………21
Measure distance from center of rear wheel to rear fender in riding condition….........................………………22
Adjust the spring preload of the rear shock……...............................................................………………………22
Check the setup of the front shock………………………....................................………………………………22
Adjust handlebar…………………………………………………………………...............................…………23
Motorcycle maintenance……...................................................…………………………………………………23
Placement of motorcycle………………………………………...............................................…………………23
Disassembly and assembly of front shock protector……………………….............................…………………23
Disassembly and assembly of front disc brake……………………………………………………………………24
Disassembly and assembly of front shock……………………………………...…………………………………24
Disassembly and assembly of clamp……………………………………………...................……………………24
Check the head steering………………………………………………………………………...................………25
Lubrication and installation of steering head bearing…………………………………………………………….25
Disassembly and assembly of front fender…………………….....………………………………………………25
Disassembly and assembly of rear shock…………………………………………………………………………26
Disassembly and assembly of seat………………………………..………………………………………………26
Disassembly and assembly of air filter…………………………...………………………………………………26
Cleaning and maintenance of air filters…………………………..………………………………………………26
Disassembly and assembly of exhaust pipe………………………………………………………………………27
Disassembly and assembly of muffler………………………....…………………………………………………27
Disassembly and assembly of fuel tank……………………..……………………………………………………27
Check the chain and clean…………………………………….......………………………………………………28
Disassembly and assembly of the chain……………………………..……………………………………………28
Check and adjust the chain tension……………………………….………………………………………………28
Inspect rear sprocket, engine sprocket and chain guide structure…….......………………………………………29
Inspection of the frame……………………………………………………........…………………………………29
Inspection of the swing arm…………………………………………………….....………………………………29
Inspection of the throttle cable………………………………………………….…………………………………30
Inspection of the handle bar……………………………………………………......………………………………30
Check and maintain the brake system………………………………………………...……………………………30
Check the free stroke of the front brake handle………………………………………........………………………30
Inspection of the disc brake………………………………………………………………….......…………………30
Check the fluid level of front brake disc………………………………………………………...…………………31
Refill the front brake disc fluid oil………………………........……………………………………………………31
Inspection of the disc brake……………………………………...........……………………………………………31
Check the free movement of the foot brake……………………………..........……………………………………32
Check the rear disc brake fluid level………………………………………….........………………………………32
Refill rear disc brake fluid………………………………………………………….………………………………32

Check the rear brake friction plate………………………………………………….........…………………………33
Tire inspection and maintenance………………………………………………………….......……………………33
Removal and installation of front wheel………………………………………………………........………………33
Removal and installation of rear wheel……………………………………………………………..………………33
Check the outside surface of the tire………………………………………………………………….........………34
Check tire pressure……………………………………….....………………………………………………………34
Check the wheel spokes…………………………………….........…………………………………………………34
Engine installation………………………………………………..…………………………………………………35
Engine maintenance and adjustment………………………………..........…………………………………………35
Inspection of bolts and nuts of cylinder and cylinder body……………….......……………………………………35
Check valve clearance…………………………………………………………....…………………………………35
Inspection of compression pressure……………………………………………….......……………………………35
Inspection of clutch control system…………………………………………………….......………………………36
Adjustment around the engine..…………………………………………………………….....……………………36
Idle speed adjustment of carburetor.............………………………………………………………………………36
Clean the carburetor………………………............………………………………………………………………36
Check shift lever position…………………………............………………………………………………………37
Adjust the position of the shift lever………………………................……………………………………………37
Check and replace spark plug…………………………………………...........……………………………………37
Lubrication system of engines…………………………………………………......………………………………38
Selection of lubrication oil…………………………………………………………...……………………………38
Lubricating oil inspection…………………………....…………………………………....………………………38
Lubricating oil replacement………………………….............……………………………………………………38
Engine repair…………………………………………............……………………………………………………39
Cylinder and valves………………………………………………………………………………………..…...…39
Notes………………………………………………………………………………………………………...….…39
Main parameters and maintenance standards of cylinder parts ……………………………………...………39
Fault symptom and cause analysis…………………………………………………………………………...……39
Removal of left cover of cylinder head……………………………………………………………………………40
Timing check………………………………………………………………………………………………………40
Removal of valve cover………………………………………………………………………………………...…41
Check valve clearance…………………………………………………………………………………………..…41
Removal of cylinder head………………………………………………………………………………………..41
Disassembly of cylinder head…………………………………………………………………………….………42
Inspection of valves and valve springs……………………………………………………………………...……42
Inspection of rocker arm and rocker arm shaft………………………………………………………………...…43
Inspection of camshaft components……………………………………………………………………………...43
Inspection of cylinder head……………………………………………………………………………....………43
Check and grind valve seats……………………………………………………………………………...………43
Inspection of valve guide………………………………………………………………………………...………44
Replacement of valve guide…………………………………………………………………………...….………44
Measure width of valve seat contact area…………………………………………………………....…...………44
Assembly of cylinder head………………………………………………………………………..………………45
Installation of cylinder head……………………………………………………………………...………………45
Cylinder block and piston……………………………………………………………………..…………………47
Matters needing attention…………………………………………………………………….…………..………47
Main parameters and maintenance standards of cylinder block and piston…………………..…………………47
Fault symptom and cause analysis…………………………………………………………….…………………48
Removal of cylinder block…………………………………………………………………….…………………48
Inspection of cylinder block………………………………………………………………………………………48
Removal of piston and piston ring……………………………………………………………..…………………49
Inspection of piston and piston ring………………………………………………………………………………49
Installation of piston ring………………………………………………………………………….………………49
Installation of piston………………………………………………………………………………………………50

Installation of cylinder block……………………………………………………………………...………………50
Clutch, driving gear, driven gear, oil pump, shifting mechanism……………………………...…………………51
Matters needing attention…………………………………………………………………………………………51
Main parameters and maintenance standards……………………………………………………….……………51
Fault symptom and cause analysis………………………………………………………………....……………52
Removal of right trim cover……………………………………………………………………..………………52
Adjustment of clutch stroke……………………………………………………………………..………………52
Removal of right crankcase cover……………………………………………………………....………………53
Clutch disassembly……………………………………………………………………....………………………53
Disassembly of driving and driven gears…………………………………………………...……………………53
Removal of engine oil pump…………………………………………………………………..…………………54
Disassemble shift mechanism……………………………………………………………………………………53
Inspection of right crankcase cover………………………………………………………………………………54
Clutch inspection…………………………………………………………………………………………………55
Inspection of driving and driven tooth……………………………………………………………………………55
Check the oil pump………………………………………………………………………………………………56
Check shift mechanism……………………………………………………………….…………………………56
Assembly of shift mechanism……………………………………………………………………………………56
Assembly of oil pump……………………………………………………………………………………………57
Assembly of driving and driven teeth………………………………………………………....…………………57
Clutch assembly………………………………………………………………........……………………………58
Installation of clutch………………………………………………………………………………..……………58
Assembly of right crankcase cover…………………………………………………………………....…………58
Assembly of right crankcase cover………………………………………………………………………………59
Right trim cover for installation…………………………………………………………………….........………59
Magneto, timing chain……………………………………………………………………………………………60
Matters needing attention…………………………………………………………………………………………60
Removal of left rear cover…………………………………………………………………………………..……60
Removal of left front cover………………………………………………………………………………….……60
Removal of magneto stator……………………………………………………………………………….………60
Removal of magneto rotor………………………………………………………………………………..………61
Removal of starting motor and starting sprocket…………………………………………………………….……61
Removal of transition plate…………………………………………………………………………………..……62
Removal of timing chain…………………………………………………………………………………..………62
Removal of tensioning arm, tensioning rod and tensioning roller………………………………………...………62
Inspection of left front cover and left back cover…………………………………………………………………62
Transition plate, starting motor, starting sprocket inspection…………………………………………………..…63
Magneto stator, rotor inspection………………………………………………………………………………..…63
Installation of tensioning arm, tensioning rod and tensioning roller…………………………………………...…63
Transition plate installation…………………………………………………………………………………….…64
Installation of starting motor and starting sprocket…………………………………………………………….…64
Installation of magneto stator…………………………………………………………………………………..…64
Installation of magneto rotor……………………………………………………………………………………...65
Installation of left cover…………………………………………………………………………………………..66
Crankcase, crankshaft, main and auxiliary shafts and speed drum……………………………………………….66
Matters needing attention…………………………………………………………………………………………66
Main parameters and maintenance standards……………………………………………………………………..66
Fault symptom and cause analysis………………………………………………………………………………..66
Decomposition of crankcase…………………………………………………………………………………......…67
Disassembly of crankshaft, main and auxiliary shaft……………………………………………………......………67
Decomposition of variable speed drum…………………………………………………………….......……………67
Inspection of crankshaft………………………………………………………………………......…………………68
Left and right crankshaft box bearing inspection……………………………………………...……………………68
Check shift fork, fork shaft and shift drum……………………………………………........………………………68

Check the combination of main and auxiliary shafts………………………………......……………………………69
Inspection of starting shaft………………………………………………………….………………….........………69
Assembly of variable speed drum………………………………………………….………………..............………69
Installation of variable speed drum, main and auxiliary shaft, crankshaft and starting shaft….........………………70
Installation of crankcase…………………………………………………………….....……………………………70
Engine troubleshooting…………………………………………………………...…………………………………71
Motorcycle cleaning…………………………………………………………........…………………………………74
Storage of motorcycle………………………………………………………………………… ……………………74
The main points of maintenance……………………………………………………………… ……………………75
Vehicle tightening torque meter…………………………………………… ………………… ……………………80
Meaning of Symbols and Technical Terms
The symbol "*" indicates that the operation requires professional knowledge and technical understanding of the
operator. If you do not have confidence to complete this operation, you can go to a professional maintenance shop
or KAYO after-sale service, to operate by professionals.
The symbol "→" indicates that the specific information is on the following page number.
DANGER/WARNING/CAUTION
In this manual, the words "DANGER/WARNING/CAUTION" will appear. Please read their following words
carefully to protect yourself and your vehicle. The meanings of "DANGER", "WARNING" and "CAUTION" are
as follows:
DANGER： Be alert to a high level of danger
WARNING： Be vigilant to moderate risk
CAUTION： Be alert to minor danger
Please note that in this manual, we only enumerate the main safety issues related to vehicle maintenance and repair,
so the contents of warning symbols cannot cover all the potential dangers during the use and repair of the vehicle.
Therefore, in addition to the related matters that "DANGER", "WARNING" and "CAUTION" indicate, users must
also have a basic knowledge of mechanical safety. If you are not sure to complete the entire maintenance and repair
operation, please consult a more experienced senior technician before operation.

Suggestions for Daily Use
The vast majority of off-road motorcycle fatalities are caused by head injuries. Without helmets, the chances of
serious injury or death from a head-hit will be much higher. Therefore, we strongly recommend that you wear a full
set of safety equipment such as helmet, goggles, gloves and boots when driving, which will save your life at the
critical moment.
The purpose of this series of models at the beginning of the design is off-road racing, without considering the
purpose of carrying passengers, and this bike does not have a rear seat, handles and pedals for carrying people, so
please be sure not to use this bike to carry other people except the driver, this behavior can easily lead to safety
accidents.
Try to avoid using non-original parts to modify the bike, and do not arbitrarily delete the original parts of the bike,
if you need to replace the parts of the bike, please choose the original parts produced by KAYO or parts from
authorized manufacturers by KAYO. In addition, KAYO is not responsible for any vehicle problems caused by
personal modification and the use of unauthorized parts.
Please check your motorcycle carefully before each use and maintain it according to the maintenance manual after
use. After the vehicle falls, please first check whether the main parts are damaged, because driving a motorcycle
with a fault is very easy to lead to the occurrence of accidents, endanger riders’ own safety.
When in use, the temperature of the engine and exhaust pipe is very high, so it will take some time to cool down
after parking. During this period, please do not touch or move the engine and exhaust pipe to avoid burns.

Vehicle Component and Position
21 TD125 Vehicle Component and Position
1 2 3 4 5 6 7
8 9 10 11 12 13 14 15 16 17 18
No.
Name
No.
Name
1
Front fender
10
Front fork
2
Headlight
11
Fuel tank
3
Handlebar
12
Carburetor
4
Vent pipe
13
Gear shift lever
5
Fuel tank cap
14
Pedal
6
Fuel tank petcock
15
Side stand
7
Chain slider
16
Chain
8
Front brake disc
17
Chain guide
9
Front brake caliper
18
Rear sprocket
19 20 21 22 23 24

25 26 27 28 29 30 31
No.
Name
No.
Name
19
Rear fender
26
Rear brake caliper
20
Muffler
27
Swing arm
21
Seat
28
Rear brake oil cup
22
Rear shock
29
Brake pedal
23
Upper clamp
30
Steel chassis
24
Lower clamp
31
Muffler pipe
25
Rear brake disc
VIN and Engine Number
VIN Number

VIN Number of 21 TD125 is carved on the frame of head pipe.
Engine Number
Engine Number of 21 TD125 is carved on the engine crankcase
body behind gear lever.
Specification
TD125 size and quality parameters
Length*Width*Height (mm)
1600*750*990
Wheelbase (mm)
1125
Weight (kg)
65
Tyre size
Front 60/100-14; Rear 80/100-12
Seat height (mm)
750
Ground clearance (mm)
265
Fuel tank capacity (L)
3.5

Engine parameter
Engine type
Single cylinder, four stroke, air - cooled, manual clutch
Displacement
119.6cc
Max power (kw/r/min)
5.6/8000
Max torque (N•m/r/min)
8.5/5000
Compression ratio
9.3:1
Gear shift type
Constant mesh 4 speed gears
Start method
Kick
Ignition system
CDI
Chain
#428；15T/41T
Frame/shock/Braking/Wheel parameters
Frame type
Steel pipe suspension frame
F ront shock absorber
Inverted front shock nonadjustable absorber, L=625mm
Rear shock absorber
Normal rear shock nonadjustable absorber, L=280mm
Rear swing arm
Steel swing arm
Handlebar
Steel handlebar
Front&rear rim
Front: 1.40×14, Rear: 1.85×12; steel rim
Front brake system
Hydraulic brake system, brake disc Φ210mm
Rear brake system
Hydraulic brake system, brake dis Φ200mm，brake pedal
Other
Air filter
Sponge filter
Motorcycle Control
Front disc brake
Hand brake handle
The front disc brake is controlled by the hand brake handle,
which is located at the right end of the handlebar and operated
by the pinching of the handle by the right hand.
The front wheel brake adopts the floating clamp disc brake,
which is installed at the lower end of the left front shock and
fixed by 2 bolts.

Front brake caliper
Throttle
Throttle
The throttle is located on the right side of the handlebar and is
controlled by right hand rotation. Turn the throttle up when
turning the handle counterclockwise, then turn the handle back
to the position after releasing the handle.
Ignition
Starting lever
The vehicle starting lever is located on the right side of the
engine, and the motorcycle engine can be started by stepping on
the starting lever.
Note:The brake should be pinched when starting to prevent the
engine from starting with the gear.
Note: there should be fuel in the fuel tank before starting the
engine, and the fuel tank switch should be in the open position.
Stall
Stall switch
The stall switch of the engine is located on the left side of the
handlebar near the handle cover. It is a round red button. Long
press it to turn off the engine and make it stall.

Fuel tank switch
Fuel tank switch
The fuel tank switch is located on the bottom left side of the
tank. By rotating the switch, you can control the fuel to flow
into the carburetor, so as to achieve control effect.
The meaning of each symbol on the oil tank switch is shown in
the figure on the left. The "OFF" sign indicates that the switch
is closed and the oil discharge is stopped.
Gear Shifting
Gearshift lever
The shift lever is located on the left side of the engine, which is
operated by stepping on and lifting the shift lever. The 21
TD125 engines are in four-gear gear with constant meshing.
Rear disc brake
Foot brake pedal
The foot brake pedal is located on the right side of the engine
and is operated by stepping.
Note: when brake, the foot brake should be the main brake,
hand brake as a supplement.
Rear brake caliper
The rear brake adopts a floating clamp disc brake, whose clamp
body is located on the right side of the rear wheel and is fixed
by a disc brake bracket.

Parking stand
The 21 TD125 uses a single stand for parking. The single stand
is on the left side of the motorcycle. When in use, straighten the
motorcycle, kick the single stand to expand it, and tilt the
motorcycle to the left so that the single stand touches the
ground and supports the motorcycle.
Notes before use
Suggestions for first-time users
1.Please read this manual before driving, especially sections "complete vehicle handling" and "riding
instructions".
2.Please perform Normative running-in before riding.
3.If any parts problems are found in use, please refer to this manual for repair or contact the dealer.
4.After each use, the motorcycle needs to be cleaned with water.
5.Do not drive in inclement weather (e.g. rainstorm, blizzard, etc.) unless necessary.
6.The company is not responsible for any vehicle problems caused by malicious acts.
Running-in process
Motorcycle engines have many parts that make relative movements, such as pistons, piston rings, cylinder blocks,
and meshing transmission gears. Therefore, in the initial stage of use, the engine must be regularly run-in. The
running-in can adapt the moving parts to each other, correct the working gap, and form a good smooth friction
surface that can withstand large loads. Only after the running-in engine is standardized can it have excellent
performance and reliability.
The recommended running-in steps are as follows:
1. 0 ~ 2.5h stage: when using a motorcycle at 50% ~ 75% throttle, the speed should be changed frequently to
avoid the motorcycle running at the same throttle for a long time; after each hour of work, let the engine cool for 5
~ 10 minutes; Avoid rapid acceleration, and the throttle cannot be either too large nor too small.
2. 2.5 ~ 4h stage: work under 50% ~ 75% throttle, at this time, the motorcycle can run at the same throttle for a
long time. During the work, the throttle can reach 100%, but the duration is not higher than 5-10 seconds;
3.4 ~ 5h stage: Use motorcycles at 75% ~ 100% throttle.
4.Above 5h: Increase the speed to 60 ~ 80km / h, knowing that the engine performance can be fully exerted.

DANGER: When driving a motorcycle, please do not accelerate at all costs. This behavior can easily lead to
engine damage and safety accidents. Therefore, please pay attention to certain driving skills when using a
motorcycle.
Riding guide
Checking items before riding
1.Check the fuel level in the tank
2.Check the oil level in the oil cup of hand brake
3.Check the oil level in the oil cup of foot brake
4.Check the foot brake clamp pad
5.Check the hand brake clamp pad
6.Check braking effect of braking system
7.Check the chain
8.Check rear sprocket, engine sprocket and chain guide
9.Check the chain adjuster
10.Check the surface of tires
11.Check tire pressure
12.Check the battery power
13.Check the thickness of the front disc brake
14.Check the thickness of the rear disc brake
15.Check the torque of each fastener
16.Check the engine gear
17.Check the cover
18.Check the fuel tank switch
19.Check protective gear if it is fully worn
Notes when ignition
Kick starting steps are as follows:

1.Turn the oil tank switch to the "ON" position;
2.Pinch the brake handle with the right hand;
3.Step the right foot on the starting lever vigorously;
4.The engine starts and process ends.
Notes when starting
1.Before starting, inspection should be carried out first, including the state of the vehicle and the driver's clothing.
2.When starting the vehicle speed should not be too fast.
3.For safety, please start in gear 1.
Notes when cornering
1.Slow down in advance when cornering.
2.When cornering, lower center of gravity to reduce side-way.
3.When cornering, do not shift gears.
Notes when acceleration
1.Do not accelerate on the corners.
2.After acceleration, shift gears in time.
Notes when gear shifting
1.Do not increase the throttle while shifting gears
2.Do not shift gears on the corners.
Notes when braking
1.When braking, the foot brake should be the main; hand brake as a supplement.
2.The level of the brake fluid in the brake fluid cup should be checked frequently.
3.When the brake fluid is insufficient, appropriate brake fluid should be added according to the maintenance
manual in time.
Notes when parking
1.When parking, slow down first and then stop.Do not brake in a sudden
2.When parking, expand the side stand and tilt the motorcycle to the left for parking.
3.Please put the gear in neutral before stopping.
Maintenance Periodic Table

Every 30 hours
Every 20 hours
Every 10 hours/after racing
Once after 1 hour riding
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Check and charge the battery

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