KAYO MOTOR AU125 User manual

ZHEJIANG KAYO MOTOR CO., LTD.
www.kayomoto.us
1
Model AU125
Service Manual

ZHEJIANG KAYO MOTOR CO., LTD.
www.kayomoto.us
2

ZHEJIANG KAYO MOTOR CO., LTD.
WWW.KAYOMOTO.COM
Instruction
This manual contains detailed information for Kayo AU125(ATV), maintenance, adjustments,
disassembly, installation, inspection points and specifications.
Please read the manual carefully and follow the instructions closely when performing
inspections and repairs, this will increase the reliability, performance and overall lifespan of
the vehicle.

ZHEJIANG KAYO MOTOR CO., LTD.
WWW.KAYOMOTO.COM
1
Contents
Chapter 1 Maintenance information
Chapter 2 Plastics and Body parts
Chapter 3 Regular Maintenance and adjustment
Chapter 4 Outer parts of engine
Chapter 5 Engine internals
Appendix Electrical schematic diagram
ZHEJIANG KAYO MOTOR CO., LTD.
All contents in this manual are subject to improve and
update without notice.

ZHEJIANG KAYO MOTOR CO., LTD.
WWW.KAYOMOTO.COM
2
Conversion table
Danger/warning/attention
Take the following warnings seriously, it’s important for regular maintenance, especially
important during engine maintenance.
Danger: Be on high alert for danger.
Warning: Be on alert for moderate danger.
Attention: Be on alert for minor danger.
This manual may contain some potential risks when performing engine work and
maintenance, please pay close attention to the above explanations, Service technician or
mechanics should have basic mechanical knowledge before performing any service,
maintenance, or inspection.
Item
Unit conversion
pressure
1kgf/cm2=98.0665kPa；1kPa=1000Pa
1PSI=0.0689kgf/cm2
1mmHg=133.322Pa=0.133322kPa
Torque
1kgf·m=9.80665N·m
volume
1mL=1cm3=1cc
1L=1000cm3
Moment
1kgf=9.80665N
Length
1in=25.4mm

ZHEJIANG KAYO MOTOR CO., LTD.
WWW.KAYOMOTO.COM
3
1. Service Information
1.1 Warnings 1.5 Torque tightening
1.2 VIN Number 1.6 Lubricant, sealant
1.3 Main parameters list 1.7 Cable, hose and wiring diagram
1.4 Maintenance parameters list
1.1 Safety precautions
Safety first
1. Wearing work clothes (coveralls), hat and safety boots suitable for the operation. In some
condition’s safety glasses, dust masks, gloves and other safety protective supplies are needed
to protect you from injury.
2. Do not run the engine in unventilated places.
3. To prevent burns, do not touch the engine or exhaust until cooled.
4. Battery solution (dilute sulfuric acid) is a strong corrosive agent; contact with the skin,
contact with eyes may cause blindness. If the battery solution accidentally touches clothes or
skin, rinse immediately with clean cold water. If the battery solution is touches eyes, please
flush immediately with plenty clean cold water and get medical treatment as soon as possible.
Battery and battery solution should be kept out of reach of children. Battery charging will
produce flammable and explosive gases, if exposed to a source of fire or spark there is a risk
of explosion or fire. Please charge in well-ventilated places.
5. As gasoline is flammable and explosive. Pay attention to sparks as well as open flames.
Vaporized gasoline may explode if exposed to open flame or sparks, please choose
well-ventilated areas away from these hazards when refueling.
6. Attention, the rear wheel, clutch or sprockets and other rotating parts and movable parts
as hands and clothes may be caught during maintenance.
Disassembly and installation precautions
1. All Parts, lubricants oils and fluids must be Kayo brand parts or Kayo recommends.
2. During disassembly, please sort and separate out the parts and fasteners of each system to
ensure that everything is put back together properly.
3. Clean the vehicle or parts to be serviced before inspection.

ZHEJIANG KAYO MOTOR CO., LTD.
WWW.KAYOMOTO.COM
4
4. Gaskets, o-rings, piston pin, piston ring, cotter pin and other onetime use parts must be
replaced after disassembling.
5. Snap rings can be deformed if opened too much during disassembly. DO NOT re-use
deform snap rings.
6. After disassembly and inspection, clean parts and blow the cleaning agents away with
compressed air before measuring. Grease the moving surfaces before assembly.
7. During disassembly, check all the necessary specifications and measure according to
directions in this manual. Make sure measurements and conditions are within specification.
8. Bolts, nuts, screws and other fasteners shall be pre-tightened and then tightened in
accordance with the specified torque in a diagonal sequence. From large to small, and from
inside to outside.
9. Inspect all rubber parts during disassembly and replace if necessary. In addition, as some
rubber pieces are not resistant to corrosive materials, please keep them from contacting
volatile oils, grease, or liquids.
10. Pack or inject recommended grease in specific places as stated in service manual.
11. Use special tools when needed for disassembly and installation.
12. Ball bearings can be rotated with finger to confirm whether the rotation is flexible and
smooth.
Bearing axial and radial clearance is oversized.
Clean and grease bearings with a tight spot when rotated. If the bearings still feel stuck
after cleaning, replace. If the bearings can’t be cleaned, replace.
If the bearing is a press fit, and becomes deformed after disassembling, replace it.
13. Bearings should be lubricated or packed with grease before assembly. Take note of the
direction of installation when assembling. When installing open or double-sided dustproof
bearing, make the manufacturer's logo and dimensions outwards.
14. Let the chamfered side towards force direction when install the Snap-ring. Do not use the
rings without elasticity. After assembly, rotate the snap-ring to confirm that it is firmly
installed in the slot.
15. It’s important to check that all fastening parts are tightened and that functions are normal
after assembling.

ZHEJIANG KAYO MOTOR CO., LTD.
WWW.KAYOMOTO.COM
5
16. Brake fluid and coolant can damage surfaces, painted parts, plastic parts, rubber parts, etc.,
do not let brake fluid contact to these parts, if brake fluid contacts these parts rinse and dilute
with water immediately.
17. When installing oil seals manufacturer’s mark and sizes face outward.
Check the oil seal before using.
Grease the oil seal lip before assembly.
18. When installing rubber hose parts, insert the rubber pipe into the fitting. If there is a hose
clamp, install the hose clamp in the hose indentation. Replace rubber hoses if dried, cracked,
or deformed
19. Clean all gasket material from surfaces of before installing new parts or reassembling.
20. Do not bend cables excessively. Kinked or damaged cables may cause poor response and
inner cables to fray and eventually break.
21. When assembling any protective caps, covers or boots make sure they are seated correctly
in the respective grooves.
Engine Break-in
Proper Engine break in is necessary on new engines and newly rebuilt engines to help
ensure that longevity and reliability of the engine components.
Recommended break-in time is 20 hours, as follows:
0~10 hours: Operate at no more than ½ throttle, keep gear changes and speed variances to a
minimum. Do not operate for extended amounts of time with a fixed throttle position. Let the
engine cool for 5 to 10 minutes after each hour of operation.Avoid quick acceleration.
0~20 hours: Operate at no more than 3/4 throttle, do not operate for extended amounts of time
with a fixed throttle position. Change gears and vary speeds as necessary. Let the engine cool
for 5 to 10 minutes after each hour of operation. Avoid quick acceleration.
Note:
During break-in period, inspect for noises and wear and follow maintenance schedule.
After Break-in period is complete schedule the unit for an inspection and service.

ZHEJIANG KAYO MOTOR CO., LTD.
WWW.KAYOMOTO.COM
6
1.2 VIN Number
Model
AU125
VIN number
Engine number
①VIN number
②Nameplate
③Engine number
3
2

ZHEJIANG KAYO MOTOR CO., LTD.
7
1.3 Specifications, Model information
No.
Item
1
Brand
KAYO
2
Type
AU125
3
Name
110cc utilityATV
4
Company
ZHEJIANG KAYO MOTOR CO., LTD.
●Dimensions, Vehicle Specifications
1
Dimension（L*W*H）（mm）
1400*850*925
2
Handlebar height（mm）
925
3
Handlebar width（mm）
730
4
Rear height（mm）
700
5
Ground clearance of seat（mm）
630
6
Min. terrain clearance（mm）
90
7
Wheelbase（mm）
900
8
Front track（mm）
700
9
Rear track（mm）
640
10
Turning radius（mm）
1650
11
Turning angle（degree）
38°±2°
12
Net weight（Kg）
105±2
13
curb weight（battery+fuel）（Kg）
110
14
Max. Speed Km/h
40（limited speed）
2

ZHEJIANG KAYO MOTOR CO., LTD.
8
●Engine Specifications
No.
Item
1
Starting type
Electric
2
Type
horizontal，Single cylinder, four stroke, oil cooling
3
Distribution way
SOHC/chain drive
4
Cylinder diameter ×
mileage（mm）
52.4*49.5
5
Compression ratio
9.0:1
6
Lubrication mode
Combination splash and pressure feed
7
Oil pump type
Rotor
8
Lubricating oil filter
type
All-flow filter, paper filter
9
Oil trademark
SAE15W-40
10
Cooling type
Air cooling
11
Cooling fluid
/
12
Air filter type
Filter with sponge filter element
13
Carburetor
Horizontal plunger type（JingkePZ22/EPA state）
14
Tank volume
2L
15
Clutch type
Dry automatic clutch
16
Gearshift method
1+1shiftear with foot、with reverse gear
17
Gear range
1 forward gear, 1 reverse gear
18
Shift type
R~N~D
19
Reduction
ratio
Forward gear D
Reverse gear R
Primary
Gear hub of clutch/primary gear
Single-s
tage
Gear ratio of forward gear
Gear ratio of
forward gear
Overall

ZHEJIANG KAYO MOTOR CO., LTD.
9
●Frame
20
Drive sprocket ratio
37/13
21
Output type
Chain drive, rear wheel drive
22
Brake type
Front and rear disc
23
Suspension type
Freestanding double rocker
24
Frame type
Steel tube and steel plate welded type
●Lubricating device
Item
Standard
Limitation
Engine oil
capacity
Change oil
800mL （No oil filter element replaced
）
－
Change oil
800mL （replace the oil filter element）
Full capacity
800mL
－
Recommended engine oil （ original ）
·four-strokesmotorcycles SAE-15W-40
For replacements, it must be within
following scope:
· APIclassification ： SGor upper grade engine
oil
· SAE specification ： refer to left table
Oil pump
rotor
Radial clearance of inner and
outer rotors
0.07 mm～0.15mm
0.2mm
Radial clearance between outer
rotor and pump body
0.03 mm～0.10mm
0.12mm
Axial clearance between rotor
surface and pump body
0.023 mm ～ 0.055mm
0.12mm
Oil pressure
1500r/min ， 90℃: 200 kPa ~400kPa ，
General 240 kPa
6000r/min ， 90℃:600 kPa ~700kPa ，
general 600 kPa
●Air intake system（see engine section）
●Cooling device Mesh oil cooler

ZHEJIANG KAYO MOTOR CO., LTD.
10
●Wheel (front and rear wheels)
Item
Standard
Limitation
Rim jump
Vertical
1.0mm
2.0mm
Horizontal
1.0mm
1.8mm
Tire
Residual groove
~
3.0mm
Air pressure
4.0 PSI
~
●Brake system
Item
Standard
Limitation
Front brake（one
with two）
disc thickness
3.5mm
3mm
Brake handle stroke
5~10mm
~
Braking force
400N*m
~
Rear brake
Disc thickness
3.5mm
~
Brake handle stroke
10~20mm
~
Braking force
500 N*m
~
●Ignition device
Item
Standard
Ignition method
CDI electric ignition
Sparking plug
Type
Resistor type spark plug
Standard
ATR7C/（torch）
Gap
0.6~0.7mm
Spark character
>8mm, one bar
Spark advance angle
Ignition coil
resistance
Primary
0.43~0.57Ω
Secondary
10.1~11KΩ

ZHEJIANG KAYO MOTOR CO., LTD.
11
Peak voltage
Primary ignition coil
>150V
Pulse
2V
●Light / Instrument / Switch
Item
Standard
Accessory inline fuse
15A
Light
Headlight left and right
12V*3W*2
Taillight/brake light
LED
Gear indicator
LED
●Valve mechanism + cylinder cover（see engine section）
●Cylinder + piston + piston ring + crank connecting link（see
engine section）
1.4 Fastener Torque Specifications
Note: When installing threads, please manually attach 2~3 turns of thread first.
Torque Specifications chart
No.
Item
install position
Bolt specification
Class
Moment N*m
1
Engine
Rear power bolt
M8
10.9
37~50
2
Up power bolt
M8
10.9
37~50
3
Down power bolt
M8
8.8
18~25
4
Suspension
Brake bolts
M10*1.25
8.8
35~45
5
Axle of upper
rocker arm
M10*1.25
8.8
35~45
6
Rear rocker arm
bolt
M10*1.25
10.9
58~71
7
Fork axle
M12*1.25
8.8
50~60

ZHEJIANG KAYO MOTOR CO., LTD.
12
8
Brake
Rear disc
M8
8.8
18~25（with
blue thread
sealants）
9
Front disc
M6
10.9
15~20
10
Disc pump
M8
10.9
29~35
11
Front brake tee
M8
8.8
18~25
12
Rear axle
Rear axle
M12*1.25
8.8
55~65
13
Nut
M27*1.5
80~90
14
Chain bolt
M6
8.8
8~12
15
Turning
Clamp locking
bolt
（hexagon）
M8
10.9
18~25
16
Steering column
locking
M8
8.8
18~25
17
Bolt of lower
raiser
M10*1.5
10.9
50~60
18
Electrical
elements
Battery box
M8
8.8
15~20
19
Muffler
installation
M8
8.8
15~20
20
Voltage regulator
ignition coil
M6
8.8
7~11
21
Oil tank,
body parts,
plastic
Oil tank
M6
8.8
7~11
22
Oil tank switch
M6
8.8
7~11
23
Pedal
M8
8.8
18~25
24
Reinforced pedal
M6
8.8
8~12
25
Plastic screw
TM6
7~11
26
Screw for
headlight and
plastic
ST4.2
3~5
●Tightening moment at specified position - engine（see engine section）
●Engine service tool（see engine section）

ZHEJIANG KAYO MOTOR CO., LTD.
13
● Engine special tool（see engine section）
1.5 lubricating grease and sealant
No.
Position
Effect
Grease
1
Dust cap for rocker arms
lubrication
XHP222
2
Ball joint of rocker arms
3
Steering column bottom
4
Joints of knuckle and wheel hub
5
Installation axle for rear fork
6
Inner sleeves of rear fork
7
Rear axle liner pipe
8
Rear axle bearing and oil seal
9
Steering column clamp
Note: please coat inside of handlebar grip with grip glue before
installing.
Engine operating materials and installation accessories (see engine
section) Engine operating materials include lubricating oil (engine oil),Grease andmay
require thread sealant or thread lock.
1.6 Wiring and cable Routing diagrams

ZHEJIANG KAYO MOTOR CO., LTD.
14
Main Harness
front brake line
Throttle cable
rear brake line
Choke cable

ZHEJIANG KAYO MOTOR CO., LTD.
15
Battery
positive
Battery
negative
Stator, ign pickup
connector
Gear indicator
Voltage regulator
Headlight
Multi Function
switch
Key Switch
Reverse indicator
Neutral indicator
Kill switch
Brake light
switch wires

ZHEJIANG KAYO MOTOR CO., LTD.
16
voltage
stabilizer
后尾灯
CDI
Ignition
coil
Voltage
regulator/rect
ifier
Tail
light

ZHEJIANG KAYO MOTOR CO., LTD.
17
2 Plastic body
2.1 Maintenance warnings
2.2 Installation torques
2.3 Seat, front guard, hood, rear body, left and right guard, plastics foot guards,
dismounting left and right footpegs
2.1 Maintenance cautions
Operation cautions
1. When replacing plastics, please install new warning labels, stickers and riveted tags
to the new plastics.
2. This chapter is about the dismounting the body plastics.
2.2 Installation torque
M8 bolt：18~25N*m
TM6 bolt：7~11 N*m
M6* bolt：8~12 N*m
2.3 Hood, handlebar, seat, plastic parts (rear body, front body and
middle guard), front guard
2.3.1 Hood
Disassembly
Push down and gently pull the hood forward to remove. (Be careful as the tabs are
easy to break).
Installation
In reverse order of disassembly. (replace hood plastic if any of the tabs broke during
disassembly).