Hitachi CM 75EBP User manual

Brand: Hitachi

Model: CM 75EBP

Type: User manual

This manual is also suitable for

CM 75EAP

PRODUCT NAME

Hitachi Engine Cutter

Models CM 75EAP

CM 75EBP

International Sales Division

TROUBLESHOOTING GUIDE ----------------------------------------------------------------------------------------------- 1

1. Troubleshooting and correction ------------------------------------------------------------------------------- 1

REPAIR GUIDE ------------------------------------------------------------------------------------------------------------------ 3

1. Precautions on maintenance, inspection and repair ----------------------------------------------------- 3

2. Inspection criteria for each section and consumable parts --------------------------------------------- 3

CONTENTS

Page

LIST Nos.

CM 75EAP: F070

CS 75 EBP: F071

Sep. 2014

-1-

1. Troubleshooting and correction

Trouble Cause Corrective action

Starter

handle

cannot be

pulled.

The crank shaft does

not rotate.

Faulty piston ring

Disassemble and

replace.

Seized piston and cylinder

Faulty crank shaft bearings

Magneto rotor contact with ignition coil

Clogging of dirt in starter pawl Clean.

The recoil starter

does not rotate.

Broken recoil starter Inspect and replace.

Startup is

impossible.

No compression

Faulty piston ring

Replace.

Worn piston

Expired oil seal service life

Worn cylinder

Defective sealing of the packing

Decompression valve trouble

Clean or replace.

Short-circuited due to foreign matter between the spark plug

electrodes.

Remove foreign matter:

In case of frequent

occurrence, replace the

spark plug and clean.

No spark

Stop switch not at startup position Adjust to startup position.

Dirty or faulty spark plug

Clean or replace.

Improperly connected plug cap

Inspect and replace.

Disconnected or improperly connected

high voltage cord

Repair or replace.

Disconnected or faulty ignition coil

ass’y

Replace.

Large gap between the magneto rotor

circumference and ignition coil ass’y

Adjust.

The spark plug does

not become wet with

fuel after repeated

starting operation.

No fuel in the fuel tank

Add properly mixed fuel

(25:1 to 50:1).

Clogged fuel filter Clean or replace.

Faulty fuel pipe

Adjust, replace or

connect.

Faulty vent hole (tank cap inside plug)

on the fuel tank

Replace.

Faulty carburetor ass’y Adjust, clean or replace.

The spark plug is wet

due to excessive fuel

supplied.

Pulling the starter handle several

times with the choke button at the

“startup” position

Dry the spark plug.

Remove residual fuel

from inside the cylinder

and crank case.

Idling stops

although

startup is

possible.

Weak spark

Dirty or faulty spark plug Clean or replace.

Improper gap between the magneto

rotor circumference and ignition coil

ass’y

Adjust.

Low compression

Worn piston ring

Replace.

Expired oil seal service life

Decompression valve trouble Clean or replace.

Good spark and

compression

Revolutions too low for idling

Adjust.

Poorly adjusted carburetor ass’y

TROUBLESHOOTING GUIDE

-2-

Trouble Cause Corrective action

Starts, but

when

accelerating

…

The engine stalls.

Clogged fuel filter Clean or replace.

Insufficient warm-up Warm up.

Poorly adjusted carburetor ass’y

Adjust.

Poor acceleration;

no increase in

revolutions

Clogged cylinder vent passage,

exhaust port and/or carbon-clogged

muffler

Clean.

Clogged air cleaner

Poorly adjusted carburetor ass’y Adjust, clean or replace.

Starts, but

…

Fluctuating

revolutions at high

speed

Dirt-clogged high-speed fuel line of the

carburetor ass’y

Clean.

Defective sealing of the packing Replace.

Faulty carburetor ass’y Adjust, clean or replace.

Excessive fuel

consumption

Clogged air cleaner Clean.

Poorly adjusted carburetor ass’y Adjust.

Abnormal vibration

Improper wheel mounting Mount properly.

Loose tightening of handle and other

parts

Check and firmly tighten

the loose parts.

Bent or broken wheel Replace with a new one.

Engine is running, but the wheel

hardly moves or is slow.

Loose belt

Adjust belt tension.

High belt tension

Belt disengaged from pulley

Firmly engage belt with

pulley.

Blunt cutting

Loose belt Adjust belt tension.

Worn-out wheel Replace with a new one.

No water supply from water

supplier

Loose connection of joint with faucet

Firmly connect both

parts.

Clogged joint Clean.

Hose of 14 mm or less in bore Replace.

-3-

This section describes repair, focusing on portions requiring frequent repair. See the TROUBLESHOOTING

GUIDE in the previous section as the context for the following descriptions.

1. Precautions on maintenance, inspection and repair

• The fuel used readily ignites; therefore, never bring the product near a flame.

• Use new gaskets at reassembly.

• Prior to disassembly for repair, remove the fuel into separate containers, and allow the tool to cool down.

• During repair, startup or running, use adequate care for portions posing the risk of burn injury or electric

shock, such as hot areas including the muffler, high voltage cord, and spark plug.

• Before running the tool with the cut-off wheel attached, make sure that there are no other people nearby.

• Ensure proper ventilation when performing repair in a small room or other poorly ventilated space.

2. Inspection criteria for each section and consumable parts

Model

Item

CM 75EAP CM 75EBP

Idling revolutions 2,500 ± 200 min

-1

No-load maximum revolutions

(with cut-off wheel)

9,800 ± 400 min

-1

Clutch engagement 3,800 ± 300 min

-1

Spindle revolutions 4,050 ± 150 min

-1

Accelerating performance Smooth acceleration

Gap between magneto rotor

and ignition coil ass’y

0.2 to 0.4 mm

Spark plug NGK BPMR7A

Gap between spark plug

electrodes

0.6 to 0.7 mm

Diamond cutter dimensions

305 mm in outside dia.

20 mm in hole dia.

355 mm in outside dia.

20 mm in hole dia.

(A diamond cutter of 25.4 mm in hole dia. is available

when using the accessory adapter collar.)

Cut-off wheel dimensions

305 mm in outside dia.

20 mm in hole dia.

3.5 mm in thickness

355 mm in outside dia.

20 mm in hole dia.

4.0 mm in thickness

(A cut-off wheel of 25.4 mm in hole dia. is available

when using the accessory adapter collar)

Max. circumferential speed of

cut-off wheel

80 m/s 100 m/s

* This engine cutter controls the maximum speed to 9,800 ± 400 min

-1

in order to prevent the cut-off wheel

from breaking. Therefore, the pulse-count type of tachometer used for detecting ignition plug firing pulses

cannot measure maximum speed. Use one of the following methods to measure maximum speed:

• Use a tachometer of the electromagnetic induction type for detecting the movement of magnetic steel in

the magneto rotor.

• Use a stroboscope or similar instrument to measure the cut-off wheel rotation (spindle speed). Make a

safety check before running the cut-off wheel, and be very careful to avoid injury.

REPAIR GUIDE

-4-

Broken piston ring

Replace.

Seized piston or cylinder

Seized or broken needle bearing of the crank

shaft

Seized or broken ball bearing of the crank

shaft

Magneto rotor contact with ignition coil Adjust.

Broken recoil starter Inspect/replace.

Clogging of dirt in starter pawl Clean.

Faulty piston ring Clean/replace.

Worn piston ring

Replace.

Worn piston

Worn or broken oil seal

Worn cylinder

Defective sealing of the packing

Decompression valve trouble

Ignition failure due to contaminant Clean (Remove contaminants.)

Stop switch not at startup position

Set to startup

position.

Dirty or faulty spark plug Clean/inspect.

Improperly connected plug cap

Inspect/replace.

Disconnected or improperly connected high

voltage cord and other wiring

Ground connection of high voltage cord and

other wiring

Inspect.

Disconnected or faulty ignition coil

Replace.

Improper gap between magneto rotor

circumference and ignition coil

Adjust.

No fuel in fuel tank

Add properly mixed

fuel (25:1 to 50:1).

Clogged fuel filter Clean/replace.

Bent fuel pipe Adjust.

Cracked fuel pipe Replace.

Disconnected fuel pipe Connect.

Faulty tank vent hole (tank cap inside plug)

Replace.

Faulty pump diaphragm of carburetor ass’y

Dirt-clogged carburetor ass’y Clean.

Poorly adjusted carburetor ass’y Adjust.

Pulling the starter handle several times with

the choke button at the “startup” position

Dry the spark plug.

Remove residual fuel

from cylinder and

crank case.

Repair flowchart

Pull the starter handle.

Is pulling possible?

Remove the spark plug to

check for sparks.

Are sparks generated?

Is there compression?

Return the spark plug

and plug cap to the

original positions, and

then perform proper

startup operation.

Is the tip of the spark plug

wet with fuel?

Is the spark plug wet due

to excessive supply of

fuel?

Yes

Is there any foreign

matter between the spark

plug electrodes?

Yes

-5-

Dirty or faulty spark plug Clean/replace.

Improper gap between magneto rotor

circumference and ignition coil

Adjust.

Worn piston ring

Replace.

Expired oil seal service life

Decompression valve trouble

Clean/replace.

Revolutions low for idling

Adjust.

Poorly adjusted carburetor ass’y

Revolutions low for idling

Adjust.

Poorly adjusted carburetor ass’y

Defective sealing of the packing Replace.

Revolutions too high for idling

Adjust.

Poorly adjusted carburetor ass’y

Worn or faulty clutch Inspect/replace.

Clogged fuel filter

Clean/replace.

Inadequate warm-up, especially in cold

weather

Warm up.

Poorly adjusted carburetor ass’y

Adjust.

Clogged cylinder vent passage, exhaust port

or carbon-clogged muffler

Clean.

Clogged air cleaner

Poorly adjusted carburetor ass’y

Adjust.

Faulty carburetor ass’y pump diaphragm

Replace.

Dirt-clogged carburetor ass’y

Clean.

Dirt-clogged high-speed fuel line of the

carburetor ass’y

Clean.

Air intake from the packing section Inspect.

Faulty carburetor ass’y pump diaphragm Replace.

Poorly adjusted carburetor ass’y Adjust.

Revolutions low for idling

Adjust.

Poorly adjusted carburetor ass’y

Clogged air cleaner Clean.

Poorly adjusted carburetor ass’y Adjust.

Does the engine stop when

rapidly decelerating from

high speed?

Yes

Does the engine stop by

pulling the throttle lever?

Does the speed increase

by pulling the throttle lever?

Do revolutions fluctuate

during acceleration?

Tilt the tool during idling.

Does the engine stop?

Does the cut-off wheel

rotate during idling?

Start the tool and set to

idling mode.

Does the engine stop?

Is fuel consumption

excessive?

Yes

-6-

Improper mounting of cut-off wheel Mount it adequately.

Loose tightening of handle and other parts

Firmly tighten the

loose parts.

Bent or broken cut-off wheel Replace.

Loose belt Adjust belt tension.

High belt tension Adjust belt tension.

Belt disengaged from pulley Engage adequately.

Poor connection of joint with faucet Connect.

Clogged joint Clean.

Hose of 14 mm or less in bore Replace.

Is there abnormal

vibration?

Is water supplied from the

water supplier?

Does the cut-off wheel

rotate?

Yes

-7-

• Spark plug

• Checking for sparks

High voltage cord

Ignited sparks

[142]

Plug cap

Metallic portion of the engine

[Bold] numbers in the descriptions below correspond to item numbers in the Parts List and exploded

assembly diagram for the Models CM 75EAP and CM 75EBP.

WARNING: Always stop the engine prior to disassembly or when replacing the cut-off wheel.

1. Checking for sparks of the spark plug

CAUTION:

• Be careful not to touch the metallic portion of Spark

Plug Ass’y BPMR7A [142] when pulling the starter

handle; otherwise, you run the risk of electric shock.

• Carefully wipe off any fuel around the plug to avoid a

sudden flash of fire.

(1) Remove Spark Plug Ass’y BPMR7A [142] from the Cylinder

[146]. Use a wire brush to clean off carbon deposits on the

electrodes of Spark Plug Ass’y BPMR7A [142], as needed.

Adjust the gap between the electrodes if necessary. Use a

cloth to wipe off any fuel on the electrodes. Remove fuel left

in the Cylinder [146], Crank Case (A) [6], and Crank Case

(B) [44] by following the procedure below.

(a) Remove the Spark Plug Ass’y BPMR7A [142] from the

Cylinder [146].

(b) Open the choke (with the Choke button [191] pushed in)

and set the Stop Switch [196] to the stop position.

(d) Pull the starter handle several times.

(2) Insert Spark Plug Ass’y BPMR7A [142] into the Plug Cap

Cord [24] and place the electrodes in contact with the

metallic portion of the engine. Under these conditions, set

the Stop Switch [196] to the startup position and pull the

starter handle.

(3) When the above steps are all completed normally, the electrodes of Spark Plug Ass’y BPMR7A [142]

should make a snapping sound to generate sparks.

2. Adjustment of the carburetor

(1) Use the idle adjust screw to adjust the carburetor.

• Use this screw to adjust the revolutions at idling. Turning the

screw clockwise increases engine revolutions; turning it

counterclockwise decreases engine revolutions.

(2) Standard setting of the carburetor

• 2,500 ± 200 min

-1

(3) Fine adjustment

• Idling adjustment

(a) Adjust the idling revolutions after the engine is fully

warmed up. (Tip on warm-up: Let the engine idle for one

minute in half-throttled status.)

(b) Use the idle adjust screw to set revolutions so that the cut-off wheel does not start rotating while

the engine runs stably.

-1

by using the idle adjust screw. (Adjust to

approx. 2,500 min

-1

Inspection and repair procedures

Gap between

electrodes

(0.6 to 0.7 mm)

Remove carbon here.

• Idle adjust screw

Idle adjust screw

Revolutions

decrease.

Revolutions

increase.

-8-

1. Disassembly and reassembly of the cleaner

[Tool required]

• Hex. bar wrench (4 mm)

(1) Disassembly

• Loosen the Cleaner Knob [184], remove Cleaner Box

(B) [187], and then take out the Pre Filter [182].

• Loosen the four Set Bolts M5 x 25 [10] by using a hex.

bar wrench (4 mm) and remove Cleaner Box (A) [189].

• Remove the Paper Filter [193] and Nylon Filter [194].

NOTE: Be careful not to let any dust get into the

engine when removing the filter.

• Remove the Rubber Rope [188] and two Bearing

Locks [190] from Cleaner Box (A) [189].

(2) Filter cleaning

• Pat the Pre Filter [182] or apply compressed air to it to

remove dust. If the filter is very contaminated, wash it

with soap and water, and then fully dry it.

• Apply compressed air to the Nylon Filter [194] in order

to remove dust.

• Pat the Paper Filter [193] or apply compressed air

from the bottom of the paper filter to remove dust.

NOTE: Never wash the Paper Filter [193].

(3) Reassembly

Reassembly can be conducted by reversing the disassembly procedure. However, special attention

should be given to the following items.

• Insert the slit portion of the Choke Rod Rubber [192] into Cleaner Box (A) [189].

For details, see “3.

Disassembly and reassembly of the carburetor ass'y.”

• Assemble the Rubber Rope [188] with one end in contact with the rib of Cleaner Box (A) [189] and the

other end aligned to the tip of the arrow mark.

Disassembly and reassembly

• Cleaner

[10]

[194]

[182]

[193]

[187]

[189]

[184]

[188]

Bottom

Apply air here.

• Rubber rope and bearing lock

[188]

[189]

[

190

]

Rear side

Rib

Arrow mark

Assemble the Rubber Rope

[188] with one end in

contact with the rib and the

other end aligned to the tip

of the arrow mark.

• Paper filter

[189]

-9-

• Cord installation

2. Disassembly and reassembly of the recoil starter and cylinder

[Tools required]

• Hex. bar wrench (4 mm)

• Long-nose pliers

(1) Disassembly

• Pull out and remove the plug cap and Shield Cover [25] from Spark Plug Ass'y BPMR7A [142].

•

Loosen the three Set Bolts M5 x 25 [10] and one Set Bolt M5 [9] by using a hex. bar wrench (4 mm),

and then remove the Recoil Starter [8] and Fan Guide [7].

• Loosen the two Bolts M5 x 16 [45] by using a hex. bar wrench (4 mm), and then remove the Cylinder

Cover [136].

• Remove the Shield Cover Ring [26] from the Shield Cover [25] by using long-nose pliers.

• Use long-nose pliers to open the five caulked portions of the Shield Cover [25] and then remove the

Shield Cover [25] from the plug cap.

NOTE: The Shield Cover [25] and Shield Cover Ring [26] are not mounted on the Models

CM 75EAP and CM 75EBP for North America.

(2) Reassembly

Reassembly can be conducted by reversing the disassembly procedure. However, special attention

should be given to the following items.

• Do not reuse the Shield Cover [25].

• Mount the Shield Cover [25] on the plug cap according to the figure on the next page.

Assemble the high-voltage cord and Cord [21]

as shown in sectional diagram below.

High-voltage cord

Plug cap

[21]

Run the high-voltage cord in the groove of the Cylinder Cover [136].

Put the Cord [21] in pawls of the

Fan Guide

[

]

for reassembl

[25]

[136]

[7]

[142]

[136]

[21]

High-voltage cord

Do not get any other part caught between the cord

terminal and terminal retaining rib of the Fan Guide [7].

Cord terminal

[23]

[7]

Terminal retaining rib

To the Recoil Starter [8]

[25]

-10-

• Shield cover

• Recoil starter

• Align the line of the Shield Cover [25] to ±0.5 mm from the top of the Cylinder Cover [136] when

inserting the plug cap and Shield Cover [25] into the Spark Plug Ass'y BPMR7A [142].

• Put the Cord [21] in the pawls of the Fan Guide [7] for reassembly.

• Put the high-voltage cord of the Ignition Coil Ass'y [23] in the groove of the Cylinder Cover [136] and

Fan Guide [7] for reassembly.

• Do not get any other part caught between the cord terminal and the terminal retaining rib of the Fan

Guide [7].

• For easier reassembly of the Recoil Starter [8], put the Recoil Starter [8] on its mounting position, pull

the starter handle, and then return it into position.

1. Put the plug cap on the Shield Cover [25]

and fold the Shield Cover [25] into two.

[25]

Bend here.

Plug cap

2. Bend and caulk five tabs of the Shield Cover [25]

by using the long-nose pliers.

3. Mount the Shield Cover Ring [26] by using

long-nose pliers.

[26]

• Shield cover mounting method

Caulk here.

Top of the Cylinder Cover [136]

[25]

Align the line of the Shield Cover [25] to ±0.5 mm

from the top of the Cylinder Cover [136].

[136]

[6]

[7]

[8]

[10]

[45]

[9]

-11-

• Carburetor ass’y

3. Disassembly and reassembly of the carburetor ass'y

[Tools required]

• Hex. bar wrench (4 mm)

• Pliers

(1) Disassembly

• Clamp both ends of the Insulator Clip [147] with pliers. The Insulator Clip [147] opens wider. Remove

the Insulator Clip [147] from the groove of the Carburetor Insulator [149] and move it toward the

Insulator Plate [148].

• Pull out the Carburetor Insulator [149] from the Cylinder [146]. Be careful not to break the insulator.

• Remove the Choke Button [191] and Choke Rod Rubber [192] from Carburetor Ass'y (C3M) [151].

• Lift up the Carburetor Bracket [181] and remove the Throttle Rod [135] from Carburetor Ass'y (C3M)

[151] and the Throttle Lever [134].

• Remove the Fuel Pipes [105] [137] from Carburetor Ass'y (C3M) [151].

• Remove Fuel Pipe (FKM) [150] from the elbow joint.

• Loosen the two Bolts M5 x 55 [195] by using a hex. bar wrench (4 mm), and then remove the

Carburetor Insulator [149], Insulator Plate [148], two Square Nuts (B) M5 [167], Carburetor Ass'y

(C3M) [151], Carburetor Packing [180], and Carburetor Bracket [181].

• Remove the Fuel Pipe [166] from Carburetor Ass'y (C3M) [151] and the Carburetor Bracket [181].

• Remove Fuel Pipe (FKM) [150] from Carburetor Ass'y (C3M) [151].

(2) Reassembly

Reassembly can be conducted by reversing the disassembly procedure. However, special attention

should be given to the following items.

• Subassemble the parts of the Carburetor Insulator [149] as shown in the figure below before mounting

the Carburetor Insulator [149] on the Cylinder [146]. Make sure the throttle valve and choke valve of

Carburetor Ass'y (C3M) [151] move smoothly after subassembly.

• Fit the lip portion of the Carburetor Insulator [149] along the groove of the Insulator Plate [148] when

mounting the Carburetor Insulator [149] on the Insulator Plate [148].

• Be careful not to bend the Fuel Pipes [105] [137] [150] [166]. For details, see “4. Connection of the

fuel pipes.”

• For reassembly of the Throttle Rod [135], first insert its tip into the throttle valve of Carburetor Ass'y

(C3M) [151], and then fit the rod to the Throttle Lever [134] while pulling the Throttle Lever [134].

• Apply 0.1 to 0.2 g of Alvania Grease RL3 to the sliding portions of the Choke Button [191] and Choke

Rod Rubber [192] (in the range of 16 to 20 mm from the end of the Choke Button [191]).

• Orient the Choke Button [191] and Choke Rod Rubber [192] correctly. Insert Cleaner Box (A) [189] into

the slit portion of the Choke Rod Rubber [192] when reassembling Cleaner Box (A) [189].

[195]

[149]

[147]

[148]

[151]

[180]

[181]

[146]

Ends

[167]

Subassemble and mount to the cylinder.

[166]

[150]

-12-

• Throttle rod and choke button

• Firmly fit the protrusion of the inner surface of the Carburetor Insulator [149] into the groove of

the Cylinder [146] when mounting the Carburetor Insulator [149] on the Cylinder [146].

• Fit the Insulator Clip [147] into the groove of the Carburetor Insulator [149] when reassembling the

clip.

[135]

[191]

[192]

[134]

[151]

Throttle valve

Choke valve

[192]

Apply 0.1 to 0.2 g of Alvania Grease RL3 to the sliding portions

of the Choke Button [191] and Choke Rod Rubber [192].

NOTE: Orient the Choke Button [191] and

Choke Rod Rubber [192] correctly.

Fit Cleaner Box (A) [189] to the slit portion

when mounting Cleaner Box (A) [189].

18±2

-13-

4. Connection of the fuel pipes

The fuel pipes are connected as shown below.

(1) Insert each fuel pipe firmly down to the root of the mating pipe.

(2) Be careful not to bend or twist any fuel pipe.

(3) Be careful not to let any fuel pipe get pinched by other parts.

(4) Position the Clip [138] about 4 to 6 mm away from the end of the pipe near the elbow joint of Fuel Pipe

(FKM) [150].

(5) The projections of Fuel Pipe (Pink) [106] and the Fuel Pipe [137] from the Return Grommet [113] and

Fuel Grommet [112] should be 100 to 105 mm and 70 to 75 mm, respectively.

NOTE: Do not mix up the pipes to be inserted into the Priming Pump Comp. [104].

• Fuel pipe connection

[104]

[151]

[106]

[137]

[148]

NOTE: Do not mix up the positions of

the Fuel Pipe [137] and Fuel

Pipe [105].

Thread the Fuel Pipe [105]

throu

h the hole as shown below.

[105]

[181]

[166]

[137]

Hole

[105]

[138]

[113]

[112]

[150] (Insert up to the scale line of the elbow joint.)

Elbow joint

[106]

[137]

[113]

[112]

[139]

[138]

7 or more

100

-14-

5. Disassembly and reassembly of the crank case and rear handle

[Tools required]

• Flat-blade screwdriver

• Double-head wrench 10 x 19 mm

• 10 mm socket torque wrench

(1) Disassembly

• Fit the tip of a flat-blade screwdriver into the slot

of the bolt portion of the Spring Holders [60] [140]

to prevent bolt rotation, and then remove the Nut

M6 [47] and Long Nut M6 [116] by using a

double-head wrench 10 x 19 mm or similar tool.

(2) Reassembly

Reassembly can be conducted by reversing the

disassembly procedure. However, special

attention should be given to the following items.

• Mount the Spring Holders [60] [140] so that the

first loop is above that of the Antivibration Springs

[120] [141] [201]. (See the upper-right figure.)

• Apply 0.1 to 0.3 g of Chemiseal L-391 (Chemitech

Inc.) to the bolt portions of the Spring Holders [60]

[140] or the female threads of Nut M6 [47] and

Long Nut M6 [116].

• Fit the tip of a flat-blade screwdriver into the slot

of the bolt portion of the Spring Holders [60] [140]

to prevent bolt rotation as shown on the right, and

firmly tighten the Nut M6 [47] and Long Nut M6

[116] without turning the Spring Holders [60]

[140] together by using a double-head wrench 10

x 19 mm or similar tool.

Then tighten the Nut M6 [47] and Long Nut M6 [116] at a specified torque of 5.5±0.5 N•m {56±5

kgf•cm} by using a 10 mm socket torque wrench to check the torque.

• Reassembly of the antivibration coil spring ass'y

[60] [140]

[47] [116]

Up to 1 mm

The Antivibration Springs [120][141][201] must not

exceed this surface of the Spring Holders [60][140].

[120] [141] [201]

•

Tightening of the nut M6

[47] [116]

• Rear handle and crank case

[6]

[47]

[116]

[60]

[201]

[141]

[120]

[60]

[140]

-15-

• Clutch

If the Spring Holders [60] [140] turn together with Nut M6 [47] and Long Nut M6 [116] at less than the

specified torque, retighten the nuts by using a flat-blade screwdriver and a double-head wrench 10 x 19

mm.

6. Disassembly and reassembly of the clutch

[Tools required]

• Hex. bar wrench (4 mm)

• Socket wrench (19 mm)

(1) Disassembly

• Loosen the three Set Bolts M5 x 25 [10] by using a hex. bar wrench (4 mm), and then remove the

Clutch Cover [35].

• Insert a socket wrench (19 mm) into the Clutch [36], turn it clockwise using an impact screwdriver or

similar tool, remove the Clutch [36], and then remove the Clutch Flange [37], Felt Packing [38], Clutch

Housing [39], Shim T0.2 [42], and Bolt Washer M12 [43].

NOTE: The Clutch [36] screwed into the Crank Shaft [1] is left-hand threaded. Do not remove Spark

Plug Ass'y BPMR7A [142] from the Cylinder [146]. Set the Decomp. [144] to the OFF

position (pulled to the near side).

(2) Reassembly

Reassembly can be conducted by reversing the disassembly procedure. However, special attention

should be given to the following items.

• Degrease the female threads of the Clutch [36] and the threads of the Crank Shaft [1] before

mounting the Clutch [36].

• The Hitachi 14.4-V impact screwdriver can apply specified torque to the Clutch [36] by tightening for

about one second.

NOTE: • Do not overtighten.

• Perform a test run after reassembly and make sure the Clutch [36] does not become

loose.

• Retighten the Flange Nut M8 [20] of the Magneto Rotor [14] after mounting the Clutch

[36] to prevent loosening.

[41] (Press-fit in the Clutch Housing [39].)

[14]

[20]

[36]

[37]

[38]

[39]

[42]

[43]

[10]

[35]

-16-

• Magneto rotor

7. Disassembly and reassembly of the magneto rotor

[Tools required]

• Jig J-363 (Code No. 6694822) (8 x 120 handle)

• Jig J-357 (Code No. 6695737) (Center bolt)

• Jig J-356 (Code No. 6695736) (Rotor extractor comp.)

• Jig J-365 (Code No. 6695739) (Shoulder bolt 5 mm)

• Socket wrenches (10 mm and 13 mm)

• Hook spanner wrench (for ĭ120 to 130)

(1) Disassembly

• Remove the two Step Bolts [19] by using a socket wrench

(10 mm). Remove the two Shims [18], two Starter Pawls

[17], two Starter Pawl Springs [15], and two Washers 0.8

[16].

• Remove the Flange Nut M8 [20] by using a socket wrench

(13 mm).

• Put the thread end of the Crank Shaft [1] and the top

surface of a commercial M8 nut at the same level, and turn

the jig J-363 (8 x 120 handle) in the arrow direction to tighten the jig J-357 (center bolt). You can now

remove the Magneto Rotor [14].

(2) Reassembly

Reassembly can be conducted by reversing the disassembly procedure. However, special attention

should be given to the following items.

• Degrease the tapered portion of the Magneto Rotor [14] and the threaded and tapered portions of the

Crank Shaft [1] before mounting the Magneto Rotor [14].

• Adjust the gap between the Magneto Rotor [14] and Ignition Coil Ass'y [23] when either is

disassembled according to “8. Adjustment of gap between the magneto rotor and ignition coil ass'y.”

• Turn the Magneto Rotor [14] clockwise around the Crank Shaft [1] for reassembly.

• Check the operation of the Starter Pawls [17] after reassembly.

• Lock the rotational movement of the Magneto Rotor [14] and then tighten Flange Nut M8 [20] at a

specified torque by using the hook spanner wrench (for ĭ120 to 130).

NOTE: • Hook the hook spanner wrench (for ĭ120 to 130) to the magnetic steel or counterweight

portion of the Magneto Rotor [14] for use.

• Retighten the Flange Nut M8 [20] of the Magneto Rotor [14] after mounting the Clutch

[36] to prevent loosening.

[15]

[16]

[17]

[18]

[19]

[20]

[1]

Hook spanner wrench (for ĭ120 to 130)

Hook the hook spanner wrench (for

ĭ120 to 130) to the magnetic steel or

counterweight portion for use.

[14]

ĭ124

• Removing the magneto rotor

J-363 (8 x 120 handle)

J-357 (Center bolt)

[14]

J-356

(Rotor extractor

comp.)

J-365

(

Shoulder bolt 5 mm

)

-17-

8. Adjustment of gap between the magneto rotor and ignition coil ass'y

(1) Loosen the two Bolts M4 x 18 [27] so as to

temporarily retain the Ignition Coil Ass'y [23].

(2) Insert a 0.3-mm thickness gauge into the

clearance between the Ignition Coil Ass'y [23]

and the periphery of the magnetic steel portion

of the Magneto Rotor [14].

(3) In this state, firmly tighten the two Bolts M4 x 18

[27].

9. Electric wiring

Perform wiring according to the following figure.

(1) Connect the connector of the Cord [21] to the Ignition Coil Ass'y [23].

(2) Connect the Earth Cord [11] to Crank Case (A) [6] using the Bolt M4 x 10 [12].

(3) Fit the Stop Switch [196] to the Rear Handle Set [114] with the “1” mark on the left side.

(4) Connect the connectors of the Cord [21] and Earth Cord [11] to the connectors of the Stop Switch [196].

(5) Place the Switch Cover [197] on the Stop Switch [196].

NOTE: Do not get the Cord [21] and the high-voltage cord pinched by other parts.

• Electric wiring

[27]

[6]

[142]

[11]

[146]

[12]

[196]

[197]

[21]

[23]

[114]

High-voltage cord

[22]

• Adjustment of gap between the magneto rotor and ignition coil

ass’y

[14]

0.2 to 0.4 mm

[27]

[23]

-18-

• Water supplier

10. Disassembly and reassembly of the muffler

[Tools required]

• Hex. bar wrench (5 mm)

• Phillips screwdriver

(1) Disassembly

• Remove the two Bolts M6 x 20 [126] and two Bolts

M6 x 50 [123] by using a hex. bar wrench (5 mm),

and then remove the Muffler [124] and Heat

Protection Plate [125].

• Remove the two Machine Screws M4 x 12 [127] by

using a Phillips screwdriver, and then remove the

Exhaust Gasket [129] and Exhaust Pipe [128].

(2) Cleaning of exhaust ports

• Use steel wire to remove carbon dust in the

exhaust ports of the Cylinder [146] and Muffler

[124], as well as in the Exhaust Pipe [128], and

then use compressed air to blow the parts clean.

NOTE: Be careful not to let any carbon dust into the cylinder, and be careful not to damage the

Heat Protection Plate [125].

(3) Reassembly

Reassembly can be conducted by reversing the disassembly procedure. However, special attention

should be given to the following items.

• Degrease the threaded holes of the Cylinder [146], Crank Case (A) [6], and Crank Case (B) [44]

before remounting the Muffler [124].

• Temporarily secure the Muffler [124] with the two Bolts M6 x 20 [126] and two Bolts M6 x 50 [123],

and then firmly tighten all the bolts.

• Do not reuse the Bolts M6 x 20 [126] and Bolts M6 x 50 [123].

11. Disassembly and reassembly of the water supplier

[Tools required]

• Hex. bar wrench (5 mm)

•

Socket wrench (19 mm)

(1) Disassembly

• Loosen the Lock Nut [75] and pull out the Water Supply Hose [76]. Loosen the Water Supply

Connector [174] by using a socket wrench (19 mm) and remove the Valve [176] and Coupler [177]

from the Mounting Plate [175].

(2) Reassembly

Reassembly can be conducted by reversing the disassembly procedure. However, special attention

should be given to the following items.

• Be careful not to bend the Water Supply Hose [76].

• Firmly insert the Water Supply Hose

[76]

into the Water Supply Connector

[174]

until it contacts the end.

• Gradually increase the tightening torque of the Coupler [177] to prevent radial protrusion of the O-ring.

[129]

• Muffler

[124]

[125]

[123]

[126]

[128]

[127]

[6]

[44]

[146]

[76]

[75]

[174]

[175]

[176]

[177]

[118]

O-ring

-19-

• Cylinder

12. Disassembly and reassembly of the cylinder

[Tools required]

• Hex. bar wrench (5 mm)

• Socket wrenches (13 mm and 19 mm)

(1) Disassembly

•

Remove Spark Plug Ass'y BPMR7A [142] by using a socket wrench (19 mm).

• Remove the four Bolts M6 x 25 [168] using a hex. bar wrench (5 mm), and then remove the Cylinder

[146].

•

Remove the Decomp. [144] and Decomp Cap [143] by using a socket wrench (13 mm).

(2) Reassembly

Reassembly can be conducted by reversing the disassembly procedure. However, special attention

should be given to the following items.

• Completely wipe off all liquid packing (ThreeBond 1207C) from the matching surfaces of the Cylinder

[146], Crank Case (A) [6], and Crank Case (B) [44], and from the surface of Cylinder Packing (C)

[169]. Be careful not to damage the matching surfaces.

• Never reuse the Bolts M6 x 25 [168]. Replace the bolts with new ones.

• Degrease the threaded holes of Crank Case (A) [6] and Crank Case (B) [44] before reassembling the

Cylinder [146].

• Do not reverse the orientation of Cylinder Packing (C) [169]. (Mount it according to the shape of the

exhaust port.)

• Be careful not to damage the cylindrical surface of the Cylinder [146] when disassembled. Remove

carbon dust from the exhaust port and combustion chamber, and then clean both parts with gasoline.

• Be careful not to let any dust enter the Cylinder [146] from its ports when reassembling the Cylinder

[146].

• Apply a thin coating of two-cycle oil to the cylindrical surface of the Cylinder [146] and the peripheral

surface of Piston (51.5) [172] when reassembling the Cylinder [146].

• Apply liquid packing (ThreeBond 1207C) to the entire faces on both sides of Cylinder Packing (C)

[169]. Fully degrease the mating faces before applying the grease.

[169]

[6]

[149]

[147]

[148]

[168]

[169]

[44]

[144]

[146]

[142]

[172]

[143]

Apply liquid packing

(ThreeBond 1207C) to the

entire faces

(

both sides

)

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Hitachi CM 75EBP User manual

Brand: Hitachi

Model: CM 75EBP

Type: User manual

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CM 75EAP

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Hitachi CM 75EBP User manual

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Hitachi CM 75EBP User manual

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