CFMoto ATV CF500-5B, CF500-5C. Service Manual

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Cylinder Head Distortion

Clean off carbon deposit from combustion chamber;

Check the gasket surface of the cylinder head for

distortion with a straightedge and thickness gauge.
Take clearance readings from several places. If any
clearance reading is out of the service limit, replace
with a new cylinder head.

Cylinder Head Distortion Service Limit: 0.05mm

Tool: Thickness Gauge

Valve Stem and Valve Guid

Lift the valve about 10mm from valve seat. Check

the valve stem deflection in the directions of X and Y
perpendicular to each other, with a dial gauge. If the
deflection measured is out of the limit, replace either
the valve or the valve guide. (If the valve stem is worn
to the limit and the clearance is found to be in
excess of the limit, replace the valve. If the valve
stem is within the limit, replace the valve guide.
Double check the clearance after replacing the
valve stem or the guide).

Valve Stem Deflection (IN & EX): 0.35mm
Tool: Micrometer
Magnetic Stand

Valve Seat Width

Coat the valve seat with color uniformly. Fit the

valve and tap the coated seat with the valve face in
a rotating manner. To get a clear impression of the
seating contact, use a valve lapper to hold the valve
head.

The ring-like dye impression on the valve face

should be continuous, without any break. The width
of the dye ring, which is the visualized seat width,
should be within the following range:

Valve Seat Width: 0.9-1.1mm

Tool: Valve Lapper

Valve Stem Run-out

Support valve stem with V block as illustrated on

the right. Check the run-out with a dial gauge.

Service Limit: 0.05mm

Tool: Magnetism Stand

Dial Gauge (1/100)

V block

Valve Head Radial Run-out

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Valve head Radial Run-out out of range:--Replace

Service Limit: 0.03mm

Tool: Dial Gauge (1/100)

Magnetism Stand

V Block

Valve Face Wear

Check each valve face for wear or damage.

Replace valve with a new one if it is found to have
abnormal wear. Measure valve head thickness T.

Valve head thickness T out of range:

---

Replace

Service Limit: 0.5mm

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Valve Stem O.D

Measure valve stem O.D with a micrometer

Service Limit:

IN: 4.975-4.990mm

EX: 4.955-4.970mm

Tool: Micrometer (0-25mm)

Valve Stem End

Check valve stem end for pitting or wear. In case of

any pitting or wear, resurface the valve stem end. If
the length T is less than service limit, replace valve
with a new one.
Valve Stem End Length

Service Limit: 2.1mm
Tool: Vernier Caliper

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Valve Spring

Valve Spring keeps valve and valve seat tight.

Weakened spring results in reduced engine power
output and chattering noise from valve mechanism.

Measure the spring free length.

Spring free length out of range:

Replace

Measure the force to compress the spring to the

specified length.
Valve spring tension out of range:

---

Replace

Service Limit: (IN/EX)
182N-210N/31.5mm
Tool: Spring Scale.

Measure valve spring incline.

Spring incline out of range:

Replace

Valve Spring Incline Limit: 2.5

/1.7mm

Assembly of Cylinder Head

Service Limit: 38.8mm
Tool

Vernier Caliper.

Install each valve spring seat;

Apply moly oil to valve stem seal and fit into

position.

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Note:

Do not reuse the valve stem seal.

Insert the valves, with stems coated with moly oil

all around.

Note:

When inserting the valve, be careful not to

damage the lip of the stem seal.

Install valve spring with small-pitch end

(

)

facing

cylinder head. Big-pitch end

(

)

is marked.

Put on the valve spring retainer. Use the valve

spring compressor to press down the spring. Fit the
two cotter halves to the stem end and release
compressor to allow the cotter

to wedge in

between seat and stem. Make sure that the rounded
lip

)

of the cotter fits into the groove

in the stem

end.

NOTE:

Knock the valve end with rubber

hammer. Make sure valve cotter is fit into groove.

Check the sealing effectiveness of cylinder head.

Dip clean solution into valve IN/EX

and check

for any leakage of valve seat

)

after a few minutes.

Tool: Valve Spring Compressor

Tweezers

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Install thermostat

Install thermostat cover

Install water temperature sensor, apply thread

locker to the thread part, tighten it to the
specified torque.

Install intake pipe, apply lubricant to 0-ring.

Camshaft

Water temperature sensor

Tightening torque: 10 N

Check camshaft for wear and run-out of cams and

journals if the engines produces abnormal noise or
vibration or lacks power output. Any of these symp-
toms could be caused by wear of camshaft.

Note:

Do not try to disassemble the camshaft/auto-

matic decompression assembly. It is not serviceable

Automatic Decompression

Move the automatic decompression weight with
hand and check if it is operating smoothly. If it is
not working smoothly, replace with a new camshaft/
automatic decompression assembly.

Cam Wear

Worn cams can often cause mistimed valve

operation resulting in reduced power output. The
limit ofcam wear is specified for both IN and EX
cams in terms of cam height

Measure with

a micrometer the cam height.

Cam height service limit:

Camshaft Journal Wear

Check whether each journal is worn to the limit

by measuring camshaft journal oil clearance with the
camshaft installed.

Camshaft journal oil clearance

15mm

Install cylinder head cover and tighten bolts evenly

and diagonally to the specified torque:

Check according to the following steps:

Clean off materials from cylinder head and cover;

Install camshaft with plastic gauge;

Tightening torque

10N

Remove cylinder head cover, read the width of the

compressed plastic gauge with envelop scale. The
reading should be taken from the widest part.

Note:

Do not turn the camshaft with plastic gauge

in place.

If the camshaft journal oil clearance exceeds the
limit,measure the outer diameter of camshaft;
Replace either cylinder head set or the camshaft if
theclearance is not correct.

Tool: Plastid Gauge

IN: 33.130mm
EX: 33.200mm

Tool

micrometer (25-50mm)

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Camshaft Journal O.D.

Measure camshaft journal O.D. with a micrometer.
If the O.D. is out of range, replace camshaft with a
new one.

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cke

959

980mm

466mm

484mm

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25mm

)

Camshaft Run-out

Measure the run-out with a micrometer. Replace

camshaft is the run-out is out of range.

Check timing sprocket and chain for wear or

damage.

Service limit: 0.10mm
Timing Sprocket and Chain

Replace with new parts if abnormal wear or damageis
found.

Tensioner and Chain Guide

Check contact surface of tensioner and chain

guide for wear and damage.
Replace with news parts if abnormal wear or
damage is found.

MOTO

Chain Tensioner

Insert screw driver

into the slotted end of ad-

justing
screw, turn it clockwise to loosen the tension and
release the screwdriver.

Check tensioner for any damage or poor function.

Damage, poor function:

—

Replace

inspect way of working stability

Check the push rod movement. If the push rod is

stuck or there is a failure with spring mechanism,
replace the chain tensioner with a new one.

Clyinder

Cylinder Distortion

Check the gasket face of cylinder for distortion with

a straightedge and thickness gauge and take
clearance readings at 7 points as illustrated. If the
largest reading at any of the 7 points of the
straightedge is out of the range, replace the
cylinder.

Cylinder Bore

Check cylinder wall for scratches, nicks or other

damage. Replace with a new one if any

Cylinder Distortion Service Limit: 0.05mm

Measure cylinder bore diameter at three points

of upper, middle and lower.

Standard Cylinder Bore:

500

522mm

Tool: Straight edge

Thickness Gauge

Tool: Cylinder Gauge Set

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Piston

Piston Diameter

Use a micrometer to measure the diameter at the

point 10mm above the piston end, as illustrated on
the right. If the measurement is less that the limit,
replace the piston

Standard

460

480mm

Limit

380mm

Tool:Micrometer (75-100mm)

Calculate the piston to cylinder clearance according
to the abovemeasurement.If the clearance is more than
0.15mm, replace the cylinder or piston, or both.

Piston Ring to Groove Clearance

Use a thickness gauge to measure the side

clearance of top

ring and 2

ring.

If the clearance exceeds the limit, replace both
piston and piston rings.

Top ring

18mm

2nd ring

15mm

Standard width of piston ring groove

Top ring

05mm

ring:

24mm

Oil ring

53mm

Standard thickness of piston ring

Top ring

970

990mm

ring

170

190mm

Tools: Thickness gauge

Micrometer

(

25mm

)

Service Limit:

MOTO

Piston Ring Free End Gap and End Gap

Before installing piston rings, use vernier caliper to
measure the free end gap of each ring, and then fit
ring into the cylinder.
Use thickness gauge to measure each ring end gap,
if any ring has an excess end gap, replace the
piston ring

Piston ring free end gap limit:

Top ring

9mm

ring

5mm

Piston ring end gap limit:

Top Ring

60mm

ring

60mm

Tool: Vernier caliper

Thickness gauge

Piston Pin and Pin Bore

Use a bore gauge to measure the inner diameter

of piston pin bore.Use micrometer to measure outer
diameter of piston pin.If out of limit, replace both
piston and piston pin.

Piston pin bore limit: 23.030mm

Use micrometer to measure piston pin outer

diameter at three points

Piston pin outer diameter limit: 22.980mm

Tools: Bore gauge (18-35mm)

Micrometer (0-25mm)

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ConnectingRod/Crankshaft
Connecting rod small end I.D.

Use a dial gauge to measure the I.D. of connect-

ing rod small end. If the measurement exceeds the
limit,replace the connecting rod.

Connecting rod small end I.D. : 23.040mm

Tool: Dial Gauge (18-35mm)

Check the movement of the small end of the rod

and inspect the wear of the small end. Thismethod
is also applicable to check and inspection of big end

Connecting Rod Deflection

Connecting Rod Deflection: 3.0mm

Tools: Dial Gauge

Magnetic stand
V-block

Connecting Rod Big End Side Clearance

Push the big end to one side, and use thickness

gauge to measure the other side clearance.
If out of limit, replace with a new crankshaft.

Connecting Rod big end side clearance: 1.0mm

Tool: Thickness Gauge

Crankshaft Run-out

Support crankshaft with blocks as illustrated.

Put the dial gauge, slowly turn the crankshaft and
measure run-out with a dial gauge.
If the run-out exceeds the limit, correct or replace
the crankshaft.

Run out limit: 0.08mm

Tools: dial gauge

Magnetic stand

V-block

MOTO

Clutch inspection

Check clutch for chipping, scrape, uneven wear or

heat discoloration. At the same time check depth of
the grooves of clutch shoes. If any of the clutch
shoes has no groove, replace the clutch.

Note:

clutch should be replaced as aset.

Clutch Wheel

Check the inner clutch wheel

for scratches,

scuffs or bluediscoloration or unevenwear. If
anydamageis found, replace the clutch wheel with
a newone.

for scratches, scuffs or blue discoloration or un-

even wear. If any damage is found, replace the clutch
wheel with a new one.

Tool: Oil seal remover

Use special tool to assemble oil seal

Tool: Oil seal installer set

Check the turning of bearing.

Abnormal damage:

—

Replace

Assembly

Apply lubricant grease to oil seal when

assembling.

Use special tool to remove oil seal

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Primary and Secondary Sheave

MOTO

Primary Sliding Sheave

Remove spacer

Remove Cam

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Check each roller and sliding face for wear and

damage.

Wear and damage:

—

Replace

Check oil seal lip for wear and damage.

Wearanddamage:

—

Replace

Note:

rollers should be replaced as a set.

Remove the oil seal

Roller inspection

Oil Seal inspection

Disassembl

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Primary Sliding Sheave and Fixed Sheave

Check the drive face for any abnormal conditions

such as damage or stepped wearing.Replace if
necessary.

Install oil seal with special tool.

Tool: Bearing install set

Assembly

Reverse the removal procedure of primary sliding
and fixed sheave for installation.
Pay attention to the following:

Apply grease to inner bore and oil seal lip.

Position 8 rollers

on the primary sliding sheave

Install 4 dampers

to cam

Install cam to primary sliding sheave.

Material: Lubricant grease

Note:

When inserting the spacer, press down the cam

so that the rollers will not come out of position

Wipe off any excessive grease

            thoroughly;
            Take care not to attach any lubricant
            grease to contact surface of drive belt.

MOTO

Install spacer

Secondary Sheave

Use special tool and holder to hold the secondary

sheave. Remove secondary sheave nut with special
t o o l

Caution:

Do not remove the ring nut before

attaching theclutch spring compressor.

Tool: Nut Wrench

Sheave Holder

Attach special tool to the secondary sliding sheave

and compress it by turning in the tool handle.

Note:

Make sure that spring end A is inserted into
slot B of the tool handle

Remove ring nut.

Disassembly

Tool: Secondary sliding sheave spring

compressor

Note:

        Since a high spring force applies to the
        secondary sliding sheave, take special
        care that the secondary sliding sheave will
        not come off abruptly

Slowly loosen tool handle and remove the

special tool.

CFMoto ATV CF500-5B, CF500-5C. Service Manual - part 8