CFMoto ATV CF500/CF500-A. Service Manual

．

Engine Overhaul Information

Engine Specification

REF.
NO

ITEM Type/SPECIFICATION

Type

Single Cylinder, 4-Storke, Liquid-cooled,

4 Valve, SOHC

Bore and stroke

87.5mm×82.0mm

3 Displacement

493ml

Compression ratio

10.2: 1

Lowest continuous idle speed with load

1300r/min±100r/min

Starting type

Electrical starting/ Recoil Starting

Ignition /

Ignition Timing

CDI Magneto ignition/BTDC10°1500r/min

Spark Plug/

Spark Plug Gap

DPR7EA-9 (NGK)/0.8mm-0.9mm

Electrical

System

Magneto Permanent

Magnet

Type

Combustion Chamber

Triangle Combustion Chamber

Carburetion Type/Model

Vacuum Diaphragm Type/MIKUNI BSR36-89

Air Filter

Sponge Element Filter

Combustion
System

Gasoline

RQ-90

Valve

System

Valve Type

SOHC/Chain Drive

Lubrication Type

Pressure & Splash

Oil Pump

Rotor Type

Filter Type

Full Flow Filter Screen

Lubrication

System

Oil Type

SAE10W-40/SF

Cooling Type

Closed Coolant Circulation

Cooling
System

Coolant Type

—35

℃

Rust-resistant antifreeze

Clutch type

Wet, Auto-centrifugal

Operation Mode

Automatic(CVT)+Parking and Gear Shifting

Gears

2 Forward Gears + 1 Reverse Gear

Shift Type/Sequence

Hand Operation/L-H-N-R-P

(CVT) Gear Ratio

2.88-0.70

Final Ratio

1.333(24/18, bevel gear)

Secondary
Ratio

1.952(41/21)

Gears

Low Gear:2.25(36/16) High Gear :1.35(27/20)
Reverse Gear:1.471(25/17)

Drive

System

Transfer
Gear Ratio

Total

Low Gear:5.857, High Gear:3.514,Reverse Gear:3.828

13 Overall

Dimension

610×568×519mm

14 Net

Weight

70kg

Output type

Front and rear shaft output

Rotational Direction of Engine Output

Clockwise (from behind engine at forward gear)

13-5

．

Engine Overhaul Information

Overhaul Data

Item Standard

Service

Limit

Remark

IN 30.6

Valve Head Diameter

EX 27.0

-----------

IN 0.05-0.10

Valve Clearance

EX 0.010-0.037

------------

IN 0.010-0.037

Clearance Between Valve
Guide and Valve Stem

EX 0.030-0.057

------------

Inner Diameter of Valve
Guide

IN & EX 5.000-5.012

-------------

IN 4.975-4.990

-------------

Outer Diameter of Valve Stem

EX 4.955-4.970

-------------

Valve Stem Play

IN & EX -------------

0.05

Length of Valve Stem End

IN & EX

2.9-3.1

2.3

Valve Head Thickness

IN & EX -------------

0.5

Play of Valve Head Seal

IN & EX

------------

0.03

Width of Valve Seat Seal

IN & EX 0.9-1.1

-------------

Valve Spring Free Length

IN & EX 40

38.8

Valve Spring Tension

IN & EX

182-210N,(when
compressed to
31.5mm)

--------------

IN 33.430-33.490

33.130

Cam Height

EX 33.500-33.560

33.200

22 0.032-0.066

0.150

Clearance Between
Camshaft Outer Diameter &
Hole

17.5 0.028-0.059

0.150

22 21.959-21.980

---------------

Camshaft Outer Diameter

17.5 17.466-17.484

---------------

22 22.012-22.025

----------------

Inner Diameter of Camshaft
Hole

17.5 17.512-17.525

----------------

Camshaft Play

0.10

Inner Diameter of Rocker Arm IN & EX

12.000-12.018

----------------

Outer Diameter of Rocker
Arm

IN & EX 11.973-11.984

----------------

Cylinder Head Distortion

0.03

0.05

Cylinder Head Cover
Distortion

0.03 0.05

13-6

．

Engine Overhaul Information

Cylinder + Piston + Piston Ring + Connecting Rod

Item Standard

Service

Limit

Remark

Cylinder Pressure

1000KPa

------------

Cylinder-Piston Clearance 0.030-0.051

0.15

Piston Skirt Diameter

87.460-87.480
(10mm form skirt end)

87.380

Inner Diameter of Cylinder

87.500-87.522

------------

Cylinder Joint Face Distortion

0.015

0.05

Top
Ring

R About

11.7

8.9

Piston Ring Free Gap

Ring

R About

9.5

Top Ring

0.15-0.30

0.60

Piston Ring Gap In Bore

Ring

0.15-0.30

0.60

Top Ring

0.04-0.08

0.180

Piston Ring Groove
Clearance

Ring

0.03-0.07

0.150

Top Ring

0.97-0.99

-------------

Piston Ring Thickness

Ring

1.17-1.19

-------------

Top Ring

1.03-1.05

-------------

Ring

1.22-1.24

-------------

Piston Ring Groove Width

Oil Ring

2.51-2.53

Inner Diameter of Piston Pin
Hole

23.002-23.008 23.030

Outer Diameter of Piston Pin

22.995-23.000

22.980

Inner Diameter of Connecting
Rod Small End

23.006-23.014 23.040

Clearance of Connecting Rod
Big End

0.10-0.55 1.0

Thickness of Connecting Rod
Big End

24.95-25.00

Crankshaft Play

0.03

0.08

Lubrication

Item Standard

Service

Limit

Remark

Clearance between Inner
and Outer Rotors

0.03mm-0.10mm 0.15mm

Clearance between Outer
Rotor and Oil Pump Body

0.03mm-0.10mm 0.12mm

Oil Pressure

130Kpa-170Kpa ( 3000r/min)

---------

Oil Type

SAE10W-40, API SF or SG ---------

When changing

1900ml

----------

When Replacing
Filter

2000ml ----------

Oil Capacity

Engine Repair

2200ml

---------

13-7

．

Engine Overhaul Information

Clutch + Transfer

Item

Standard

Service Limit Remark

Clutch Plate Inner diameter 140.00-140.15

140.50

Clutch Engagement Speed

1800-2400r/min

---------

Clutch Lock Speed

3300-3900r/min

---------

Drive Belt Width

35.2

33.5

Free length of Secondary
Sheave Spring

168 160

Shift Fork to Groove
Clearance

0.10-0.40 0.50

Thickness of Left Shift Fork

5.8-5.9

------------

Thickness of Right Shift Fork

5.8-5.9

------------

Shift Fork Groove Width

6.0-6.2

------------

Drive Output Gear Groove
Width

6.0-6.2 ------------

Cooling System

Item Standard

Service

Limit

Remark

Thermostat Valve Opening
Temperature

68-74

℃

----------

Thermostat Valve Lift

3.5-4.5mm ( at 95

℃

)

----------

Radiator Cap Opening
Pressure

93.3-122.7Kpa ----------

Water
Temperature (

℃

)

Resistance (

Ω

) ----------

154+16

80 52+4

100 27+3

Corresponding Relation
Between Water-temperature

Transducer’ resistance and

water-temperature

120 16+2

OFF--ON

℃

------------

Functioning Temperature of
Thermoswitch

ON--OFF

℃

------------

Coolant Type

-35

℃

antifreeze, corrosion-resistant, high

boiling point coolant

------------

13-8

．

Engine Overhaul Information

Carburetor

Item Standard

Remark

Carburetor Type

MIKUNI BSR36-89

I.D. Mark

07G0

Carburetor Barrel Size

36mm

Engine Idle Speed

1300r/min+100r/min

Main Jet (MJ)

N10221-130#

Main Air Jet (MAJ)

MD13/24-35#

Jet Needle (JN)

J8-5E26

Needle Jet (NJ)

785-401011-P-OM

Pilot Jet (PJ)

N224103-22.5#

Pilot Jet Screw (PS)

604-16013-1A

Electrical System

Item Standard

Remark

Type

NGK;DPR7EA-9

Spark Plug

Gap

0.8-0.9

Spark Character

>8mm

Ignition coil
Resistance

Primary

0.1

Ω

-0.5

Ω

Secondary

Ω

-22

Ω

Magneto Coil
Resistance

Pick-up 150

Ω

-300

Ω

Magneto Voltage (Without load)

>100V(AC),5000r/min

Max. Magneto Output Power

300W, 5000r/min

Regulated Voltage

13.5V-15.0V, 5000r/min

Primary Peak Voltage of Ignition Coil

>150W

Starter Relay Coil Resistance

>120W

Starter Relay Coil Resistance

Ω

-5

Ω

Auxiliary Starter Relay Coil Resistance

90-100

Ω

13-9

．

Engine Overhaul Information

Tightening Torques

Item

Quantities

Thread Size (mm)

Tightening Torque

(N.m)

Remark

Reverse Gear Sensor

M10*1.25

Spark Plug

M12*1.25

Water-temperature
Sensor

1 Rc1/8

Apply

Thread

Locker

Adjusting Nut,
Valve Clearance

4 M5

Nut, Primary Sheave

M20*1.5

115

Nut, Secondary
Sheave

1 M20*1.5

115

Ring Nut, Secondary
Sheave

1 M30*1

100

Nut, Front Drive Shaft

M14*1.5

Nut, Drive Bevel Gear

M22*1

145

Nut, Driven Bevel
Gear

1 M16*1.5

150

Fixing Nut, Clutch

M18*1.5

Counter Clockwise

Limit Nut, Drive Bevel
Gear Bearing

1 M60

110

Apply

Thread

Locker

Nut, Universal Joint
Yoke

1 M55

Counter Clockwise,

Apply Thread Locker

Bolt, Rocker Arm
Shaft

2 M14*1.25

Oil Drain Bolt

M12*1.5

Bolt, Overriding
Clutch

6 M8

Apply

Thread

Locker

Bolt, Magneto Stator

Apply Thread Locker

Screw, CVT Plate

Apply Thread Locker

Bolt, Oil Pipe

M14*1.5

Bolt, Oil Pump

Bolt, Pressure
Release Valve

2 M6

Bolt, Drive Bevel
Gear Cover

4 M8

Bolt, Driven Bevel
Gear Cover

4 M8

Bolt, Gear Limit

M14×1.5

Bolt, Recoil Starter

M10×1.25

13-10

．

Engine Overhaul Information

Tightening Torques

Item Quantiti

Thread Size

(mm)

Tightening Torque

(N.m)

Remark

14 M6

Bolt, Crankcase

3 M8

Bolt, Driven Sector Gear

Bolt, Oil Filter

M20×1.5

Bolt, Oil Starter Motor

Bolt, Cylinder Head

M10

Bolt, Cylinder Head

Bolt, Cylinder (Upper &
Lower)

4 M6

Bolt, Cylinder Head
Cover

12 M6

Bolt, Chain Tensioner

Nut, Chain Tensioner

Bolt, Fan Motor

Bolt, Thermostat
Housing

2 M6

Bolt, Water Pump Cover

Bolt, Water Pump

Fixing Bolt, Timing
Chain

2 M6

Apply Thread Locker

4.5-6

8-12

Other Bolts

M8 18-25

13-11

．

Engine Overhaul Information

Maintenance Tools

Measurement Tools

No. Description Specification

Purpose

Vernier Caliper

0-150mm

For measuring the length and thickness

Micrometer

0-25mm

For measuring outer diameters of rocker arm, valve stem
and camshaft

3 Micrometer

25-50mm For

measuring the max. lift of camshaft

Micrometer

75-100mm

For measuring piston skirt

Cylinder Gauge

For measuring cylinder bore diameter

Small Bore Gauge

10-34mm

Fore measuring inner gauge of rocker arm, piston pin bore,
connecting rod small end bore

7 Dial

Indicator

1/100

For measuring the play

Straightedge Gauge

Plane measuring

Feeler Gauge

Plane and valve clearance measuring

Fuel Level Gauge

For measuring the carburetor fuel level

11 Thickness

Gauge

For

measuring the clearance

Spring Balance

For measuring the spring tension

13 Tachometer

For

measuring engine speed

Oil Pressure Gauge

For measuring oil pressure

15 Compression

Gauge

Adapter

For measuring cylinder compression

Radiator Cap Tester

For measuring radiator cap opening pressure

Ohmmeter

For measuring resistance and voltage

Ammeter

For measuring current/switches

Thermometer

For measuring liquid temperature

Timing Light

For checking the ignition timing

Torque Wrench

For measuring the tightening torque

General-purpose and Auxiliary Tools

Alcohol Burner

Heating up

Magnetic Stand

For micrometer

Slab

Auxiliary tool for measuring

V-block

For measuring the play

Tweezer

For installation of valve cotter

Circlip Pliers

For removal and installation of circlips

Long Nose Pliers

For removal and installation of retainers

Impact Driver

For removal of cross-headed bolts

30 (-)

Driver

31 (+)

Driver

13-12

．

Engine Overhaul Information

Special Tools

No. Description Specifications

Purpose

Spark Plug Wrench

Removal and installation of spark plug

Clutch Holder

For removing/installing clutch carrier nuts

Oil Filter Wrench

Removal and installation of oil filter cartridge

Piston Pin Puller

For removal of piston pin

Flywheel Puller

For removal of magneto rotor

Crankcase Separating Tool

For separation of left and right crankcase

Crankshaft Remover

For removal of crankshaft from left crankcase

Crankshaft Installation Set

For installing crankshaft to left crankshaft

Valve Spring Compressor

For removal and installation of valve spring

Valve Seat Cutter

For valve-seating

Ring Nut Wrench

Removal/installation of CVT secondary sheave

12 Sheave

Holder

Removal/installation of CVT secondary sheave

Sheave Spring Compressor

Removal/installation of CVT secondary sheave

Couple Gear/Middle Shaft
Tool

Removal/installation of the coupling gear nut

Bearing Driver

Set

For installation of bearing and oil seal

Bearing Removing Tool

Set

For removal of bearing

Oil Seal Removing Tool

For removal of oil seal

Universal Joint Holder

For removal/installation of the universal joint yoke nut

13-13

．

Engine Overhaul Information

Materials for Operation and Fixing

Materials for engine operation engine oil, grease and coolant. Fixing materials include sealant, thread locker,
etc.

13-14

Description Type

Application

Area

Remark

Lubricating
Oil/Engine Oil

SAE10W-30
or SAE10W-40
or SAE20W-50
API service classifications
SF or SG

Cylinder bore
Crankcase
Refer to Engine Lubrication
System (

→

14-14)

capacity
1900ml
(for changing oil)
2000ml
(for replacing filet)
2200ml
(for engine repairing)

Molybdenum
lubrication oil

piston pin

、

valve stem

、

valve

oil seal

、

camshaft

Lubricating Grease

#3 MoS

Lithium Base

Grease

Oil seal lip, O-ring and
sealing faces of other
rubber seal materials,
bearings with seals, CVT
bearing and collar

Coolant

-35

℃

antifreeze,

corrosion-resistant, high
boiling point coolant

Cooling system

、

Water-seal Capacity according to

radiator and water hose
system

Joint Face Sealant

Joint face of crankcase,
crankcase and cylinder,
cylinder head and cover

Thread Locker

Thread Parts

See 10-10, 10-11

14. Checks & Adjustment

14-1

Periodic Maintenance ……………………………………………………….14-2

Procedures of Maintenance and Adjustment…………….………………..14-3

Valve Clearance……………………………………………………………...14-3

Engine Idle Speed…………………………………………….…….………..14-4

Spark Plug………………………………………………………...…….…….14-4

Air Filter………………………………………………………………………..14-5

Fuel Hose, Carburetor………………………………………………………..14-6

Drive Belt……………………………………………………...……………….14-7

Inspection of Lubrication System……………………………………..……..14-8

Inspection of Cooling System………………………………………………..14-10

Inspection of Cylinder Pressure………………………………………..……14-11

Inspection of Oil Pressure………………………………………………...….14-12

Inspection of Clutch Engagement and Lock-up……………………..……..14-13

14. Checks & Adjustment

Periodic Maintenance Table

The table below lists the recommended intervals for all the required periodic maintenance work necessary to

keep the vehicle at its best performance and economy. Maintenance intervals are expressed in terms of

kilometer, miles and hours, whichever occurs first.

Note: More frequent maintenance may be required on vehicles that are used in severe conditions.

Initial 200

Every 1000

Every 2000

Miles

Initial 100

Every 600

Every 1200

Interval

Item

Hours

Initial 20

Every 40

Every 80

Remark

Valve Clearance

I -- I

IN: 0.05~0.10
EX:0.17~0.22

Idle Speed

1300±100r/Min

-- -- I

Spark Plug

Replace every 6000Km

No carbon deposit
Gap: 0.8~0.9mm

Air Filter

Replace every 2000Km

Fuel Hose, Carburetor

Replace every 4 years

Clutch --

Drive Belt

Engine Oil

Oil Filter

Coolant Level

Water Hose & Pipes

Coolant

Replace every 2 years

I=Inpection and adjust, or replace if necessary

R=Replace

C=Clean

14-2

14. Checks & Adjustment

Procedures of Maintenance & Adjustment

This section describes the maintenance procedures for
each item mentioned in the Periodic Maintenance Chart.

VALVE CLEARANCE

Excessive valve clearance results in valve noise and
insufficient valve clearance results in valve damage and
reduced power.
Check the valve clearance at the period indicated above
and adjust the valve clearance to specification, if
necessary.

Remove cover plate , recoil starter

①

②

Remove inspection cap

③

on left crankcase.

Remove 2 valve adjusting cover

④

Turn the crankshaft until the line

⑤

of T.D.C. on rotor is

aligned with mark

⑥

of inspection hole on left

crankcase.

Insert feeler gauge to check the clearance between

the valve stem end and the adjust bolt on the rocker
arm.

Note:

The valve clearance must be adjusted when the

engine is cold.

Adjust the valve clearance when the piston is at the

Top Dead Center (T.D.C.) on the compression stroke.

If the clearance is incorrect, bring it into the specified range
using the special tool.

Loosen valve adjust bolt and nut, insert a feeler gauge
between the valve stem end and valve adjusting bolt,
tighten valve adjust bolt, make sure it slightly contacts the
feeler gauge, tighten bolt and nut.

14-3

Inspect initially at 20-hour break-in and every 40 hours
or every 1000km thereafter. Inspect the clearance after
removing cylinder head.

Valve Clearance (When cold)
IN: 0.05-0.10mm EX: 0.17-0.22mm

14. Checks & Adjustment

Take out the feeler gauge, measure the clearance.
If the clearance is incorrect, repeat the above steps until
the proper clearance is obtained.
Locknut: 10 N.m

Install:
2 valve adjusting cover;
Inspection cap;
Recoil starter;
Cover plate;
Apply a small quantity of THREAD LOCKER to recoil
starter fixing bolts.

Tools:

Valve adjuster
Feeler gauge

Material:

Thread Locker

ENGINE IDLE SPEED

Start the engine and warm it up for several minutes,
measure engine speed with a tachometer. Set the
engine idle speed between 1200~1400 r/min by turning
the throttle stop screw of carburetor.

Engine idle speed: 1300r/min±100r/min

Note:

Make this adjustment when the engine is hot

Tool:

Tachometer

SPARK PLUG

Inspect initially at 20 hours run-in and every 80 hours or
2000km thereafter. Replace every 6000km.
Remove the spark plug with a special tool

Specification:

DER7EA-9(NGK)

If the electrode is extremely worn or burnt, or spark plug
has a broken insulator, damaged thread, etc, replace the
spark plug with a new one.

14-4

Caution:

Securely tighten the locknut after completing

adjustment

Inspect initially at 20 hours run-in and every 40
hours or 1000km thereafter.

14. Checks & Adjustment

In case of carbon deposit, clean with a proper tool.

SPARK PLUG GAP

Measure the spark plug gap with a feeler gauge.
Out of specification:

→

Adjust

Spark plug gap: 0.8-0.9mm

Installation:

Tightening Torque:

18 N.m

Tool:

Spark Plug Wrench, Feeler Gauge

Air Filter

If the air cleaner is clogged with dust, intake resistance
will be increased, with a resultant decrease in power
output and an increase in fuel consumption. Check and
clean the air filter as following:
Remove fixing clamp

①

and top cover

②

Note:

Be careful not to drop the o-ring into the air filter box that
is attached to the air filter top cover.
Loosen screw

③

, remove filter element

④

, separate

support

⑤

, filter element

⑥

and filter element seat

⑦

Fill a wash pan of a proper size with a

non-flammable cleaning solvent A. Immerse the
filter element in cleaning solvent and wash it.

Press the filter element between the palms of both

hands to remove the excess solvent. Do not twist or
wring the element or it will tear.

Immerse the element in engine oil B, and then

squeeze out the excess oil leaving the element
slightly wet.

14-5

Caution:
Check the thread size and reach when replacing the
spark plug. If the reach is too short, carbon will be
deposited on the screw portion of the spark plug hole and
engine damage may result.

Caution:
To avoid damaging the cylinder head threads; first,
tighten the spark plug with fingers, and then tighten it to
the specified torque using the spark plug wrench.

Inspect every 40 hours or 1000 km, clean it if
necessary.

14. Checks & Adjustment

A--Non-flammable cleaning solvent
B—Engine oil SAE#30 or SAE10W/40.

Inspect the filter element for tears. torn element must be
replaced.

Remove the drain plug

⑧

of air box to drain out any

water.

Fuel Hose

Inspect every 80 hours or 2000 km, replace every 4
years.
Inspect the fuel hose for damage and fuel leakage. If any
damages are found, replace the fuel hose with a new
one.

Drive Belt

Removal:
Remove CVT cover

Hold the primary sheave with special tool and loosen
primary sheave nut.

Special Tool: Rotor Holder

Remove primary sliding sheave 1;
Hold the secondary sheave with special tool and loosen
secondary sheave nut. Remove secondary sheave
together with drive belt.

Special Tool: Rotor Holder

Remove drive belt from secondary sheave

14-6

Warning:

Never use with gasoline or low flash point solvents to
clean the filter element

Note:
If driving under dusty conditions, clean the air filter element
more frequently. The surest way to accelerate engine wear
is to operate the engine without the element or with torn
element. Make sure that the air filter element is in good
condition at all times.

CFMoto ATV CF500/CF500-A. Service Manual - part 9