Robin EX17, EX21, EX27 Service Manual

SERVICE MANUAL

Models

EX13, 17, 21, 27 ENGINES

PUB-ES1934 Rev. 10/05

940 Lively Blvd. • Wood Dale, IL 60191 • Phone: 630-350-8200 • Fax: 630-350-8212

e-mail: sales@robinamerica.com • www.robinamerica.com

CONTENTS

Section Title Page

1. SPECIFICATIONS ...................................................................................................... 1

2. PERFORMANCE ...................................................................................................... 2

3. FEATURES ...............................................................................................................7

4. GENERAL DESCRIPTION OF ENGINE COMPONENTS........................................ 8

5. DISASSEMBLY AND REASSEMBLY .................................................................... 14

5-1 PREPARATIONS AND PRECAUTIONS............................................................14

5-2 SPECIAL TOOLS .............................................................................................. 14

5-3 DISASSEMBLY PROCEDURE.......................................................................... 15

5-4 REASSEMBLY PROCEDURE........................................................................... 29

6. ENGINE OIL ...........................................................................................................47

7. MAGNETO .............................................................................................................. 48

8. WIRING DIAGRAM................................................................................................. 51

9. ELECTRIC STARTER............................................................................................. 53

10. OIL SENSOR .......................................................................................................... 55

11. AUTOMATIC DECOMPRESSION SYSTEM........................................................... 56

12. CARBURETOR....................................................................................................... 57

13. RECOIL STAR TER................................................................................................. 61

14. INSTALLATION ...................................................................................................... 66

15. TROUBLESHOOTING............................................................................................ 68

16. STANDARD REPAIR TABLES ............................................................................... 74

15-1 STANDARD DIMENSIONS AND LIMITS OF USE ........................................... 74

15-2 TIGHTENING TORQUE .................................................................................... 80

17. MAINTENANCE AND STORAGE ..........................................................................81

1. SPECIFICATIONS

)

Model EX13D EX17D EX21D EX27D

Type

Bore & Stroke

Piston Displacement

Compression Ratio 8.5 8.3

Continuous Output kW(HP)/r.p.m.

Maximum Output kW(HP)/r.p.m. 3.2(4.3)/4000 4.2(5.7)/4000 5.1(7.0)/4000 6.6(9.0)/4000

Maximum Torque

Direction of Rotation Counterclockwise as viewed from the P.T.O.shaft side Valve Arrangement Overhead cam system Cooling System Forced air coo ling system Lubrication System Splash lubrication system

Lubricant

mm (in.)

ml (cu.in.)

N・m/r.p.m. (kgf・m/r.p.m.) (ft・lb./ r.p.m.)

58 x 48

(2.28 x 1.89)

126

(7.69)

1.9(2.6)/3000

2.2(3.0)/3600

8.1/2500 (0.83/2500) (6.01/2500)

Automobile engine oil ;Grade SE or higher (SG,SH or SJ in recomended)

SAE 10W-30-----Under ordinary atmospheric temperatures SAE 5W-30-------In cold areas

Air-Cooled, 4-Cycle, Slant Singl e-Cyl inder,

Horizontal P.T.O. Shaft, OHC Gasoline Engine

67 x 48

(2.64 x 1.89)

169

(10.31)

2.6(3.5)/3000

2.9(4.0)/3600

11.3/2500

(1.15/2500)

(8.34/2500

67 x 60

(2.64 x 2.36)

211

(12.87)

3.2(4.4)/3000

3.7(5.0)/3600

13.9/2500

(1.41/2500)

(10.26/2500

75 x 60

(2.95 x 2.36)

265

(16.17)

4.4(6.0)/3000

5.1(7.0)/3600

18.6/2500 (1.9/2500)

(13.74/2500

Capacity of Lubricant L 0.6 1.0 Carburetor Horizontal draft, Float type Fuel Automobile unleaded gasol ine

Fuel C onsumption Rate

Fuel Supply System Gravity type Fuel Tank Capaci ty L 2.7 3.6 6.1 Ignition System Transistorized magneto Spark Plug NGK BR-6HS (CHAMPION RL86C)

Charging Capaci ty (Option)

Starting System Recoil starter Recoil starter / Electric starter (Option) Governor System Centrifugal flyweight system

Dry Weight

Dimensions (L x W x H)

＊Specifications are subject to change without notice.

g/kW・h (g/HP・h)

V-A ------------- 12-1 A , 3 A , 1 6.7 A (Opt i on)

kg (lb.)

mm (in.)

(11.7x13.4x12.5)

(30.87)

297 x 341 x 318

367 (270) at continuous rated output

(33.08)

304 x 354 x 335

(12.0x13.9x13.2)

(12.2x14.4x13.2)

(35.28)

311 x 366 x 335

(46.31)

351 x 420 x 410

(13.8x16.5x16.1

- 1 -

2. PERFORMANCE

2-1 MAXIMUM OUTPUT

The Maximum output is the output of an engine with its throttle valve fully opened and considering that all the moving parts are properly broken in.

A new engine may not produce full maxim um output while its moving parts are still not broken-in.

NOTE : Pow er curves shown in the follo wing charts are made in conformity with SAE internal combustion engine standard test code J1349.

2-2 CONTINUOUS RATED OUTPUT

The continuous rated output is the output of an engine at optimum gov erned speed which is most fav orable from the view point of engin’ s life and fuel consumption.

When the engine is installed on a certain equipment, it is recommended that the continuous output required from the equipment to be kept below this continuous rated output.

2-3 MAXIMUM TORQUE

The maximum torque is the torque at the output shaft when the engine is producing maximum output at a specific r.p.m..

- 2 -

2-4 PERFORMANCE CURVES

EX13D

9.0

0.9

[HP]

5.0

4.0

3.0

MAXIMUM TORQUE

4.0

3.5

MAXIMUM HORSEPOWER

3.0

2.5

8.0

7.0

0.8

0.7

TORQUE

OUTPUT

2.0

1.0

2.0

CONTINUOUS RATED HP

1.5

RECOMMENDED HORSEPOWER RANGE

1.0

0.5

2000 2400 2800 3200 3600 4000

r.p.m.REVOLUTION

- 3 -

EX17D

12.0

1.2

[HP]

6.0

5.0

4.0

4.5

4.0

3.5

3.0

2.5

MAXIMUM TORQUE

MAXIMUM HORSEPOWER

11.0

10.0

9.0

1.1

1.0

0.9

TORQUE

3.0

OUTPUT

2.0

1.0

CONTINUOUS RATED HP

2.0

RECOMMENDED HORSEPOWER RANGE

1.5

1.0

0.5

2000 2400 2800 3200 3600 4000

r.p.m.REVOLUTION

- 4 -

[PS]

5.5

EX21D

MAXIMUM TORQUE

15.0

14.0

13.0

12.0

1.5

1.4

1.3

1.2

7.0

6.0

5.0

4.0

3.0

OUTPUT

5.0

TORQUE

MAXIMUM HORSEPOWER

4.5

4.0

3.5

3.0

CONTINUOUS RATED HP

2.5

RECOMMENDED HORSEPOWER RANGE

2.0

1.0

1.5

1.0

0.5

2000 2400 2800 3200 3600 4000

r.p.m.REVOLUTION

- 5 -

EX27D

[HP]

9.0

8.0

7.0

6.0

MAXIMUM TORQUE

7.0

6.5

MAXIMUM HORSEPOWER

6.0

5.5

5.0

4.5

4.0

CONTINUOUS RATED HP

19.0

18.0

17.0

16.0

15.0

1.9

1.8

1.7

1.6

1.5

TORQUE

5.0

4.0

OUTPUT

3.0

2.0

1.0

3.5

RECOMMENDED

3.0

2.5

2.0

1.5

1.0

0.5

0 2000 2400 2800 3200 3600 4000

HORSEPOWER RANGE

r.p.m.REVOLUTION

- 6 -

3. FEATURES

3-1 EXTREMELY SILENT - SOFT TONE QUALITY

EX engines are 2dBA quieter and softer in tone than other engines in the same class.

This quiet and soft tone is achieved b y:

- A reduction in mechanical noise realized by emplo ying sophisticated OHC system.

- Employment of an optimized capacity Rigid Muffler.

3-2 EXTREMELY EASY START - NO KICK-BACK

Reliable Starting and Less Pulling Force are achieved by:

- Sophisticated Mechanical Compression Release System as well as newly designed Combustion Chamber.

- EX engines start instantly even at minus (-) 10°C, without any perceptible kick-back.

3-3 EXTREMELY EASY MAINTENANCE

Extreme ease of maintenance is realized by:

- High Parts Commonality

simplifies maintenance & lowers repair cost due to fe w er parts for service. More than 90% of component parts are in common between more than two models, in such as Muffler, Intake and Exhaust Valves, Valve Springs, etc. Furthermore, more than 50% of component parts are in common among EX13, EX17 and EX21, in such as Chain Guide, Air Cleaner, Ignition Coil, etc.

- Only with ordinary tools, routine maintenance, assembly and disassembly can be performed.

3-4 EXTREMELY ADVANCED TECHNOLOGY

Extreme reliability and durability are achieved b y:

- Heavy Duty Chain Driven OHC System

Oval type case-hardened steel links enhance performance and resist stretching, which result in extended maintenance free operation.

- Completely New Main Bearing Cover’s Design

Flush-mounted main bearing cover with lower moment of def ormation significantly increases reliability and engine life.

- Superior Cooling and Lubrication System

Heat reduction is achieved b y more efficient, larger and more numerous cooling fins on cr ankcase, cylinder and mounting base, as well as by outstanding oil delivery system.

- Large Ball Bearings on both ends of crankshaft for maxim um stability under demanding loads .

- Cast Iron Cylinder Liner resists wear

3-5 EXTREME POWER AND PERFORMANCE

Extremely Higher Po wer and Lo wer Fuel Consumption are realiz ed b y :

- High speed and homogeneous combustion achiev ed by sophisticated Pentroof Combustion Chamber which includes Intake and Exhaust Valves located at optimum angle.

- Straight Intake Port with minimal air flow resistance.

Environmentall y friendly

EX engines comply with EPA Phase 2 and CARB Tier II Emission Regulations in the USA.

Extreme application compatibility

With four versatile models, existing slant-cylinder engines can be easily replaced.

- 7 -

4. GENERAL DESCRIPTION OF ENGINE COMPONENTS

4-1 CYLINDER AND CRANKCASE

The cylinder and crankcase are aluminum die-casting as a single piece. A special cast iron cylinder liner is molded into the aluminum die-casting. The crankcase has a mounting surface on the output shaft side to which the main bearing cover is attached. The cylinder is inclined to the right at an angle of 25 degrees from the horizontal as viewed from the output shaft side.

Fig. 4-1

4-2 MAIN BEARING COVER

The main bearing cover is an aluminum die-casting, which is mounted on the output shaft side of the crankcase. By removing the main bearing cover, the inside of the engine can be inspected with ease. Pilots and bosses are machined into the cover to f acilitate the direct coupling of the engine with machines such as generators and pumps. There is an oil filling port, with oil gauge, on either side of the cover.

4-3 CRANKSHAFT

The crankshaft is made of spheroidal graphite cast iron, and the crank pin is high-frequency induction-hardened. The crank sprocket used to drive the chain and the gear used to drive the governor gear are pressed into the output end of the shaft.

4-4 CONNECTING ROD AND PISTON

The connecting rod is a specially heat-treated aluminum alloy die-casting. Its large and small ends function as bearings. A splasher built into the connecting rod lubricates by splashing engine oil. The piston is an aluminum alloy casting with groov es for mounting two compression rings and one oil ring.

Fig. 4-2

Fig. 4-3

- 8 -

Fig. 4-4

4-5 PISTON RINGS

The piston rings are made of special cast iron. The profile of the top ring is a barrel face or tapered face, and that of the second ring is a tapered face. There are 2 types of oil ring depending on the engine specification. As those are interchangeable, the cutter ring with coil expander type can be selected as the spare part.

BARREL

TOP

RING

(EX13/27)

TAPER (EX17/21)

Fig. 4-5

4-6 CAMSHAFT

The camshaft and the sprocket are made of special sintered alloy. They are constructed as a single piece. The camshaft is provided with intake and exhaust cam, and the decompression release lever is mounted on the sprocket shaft end side.

4-7 VALVE ARRANGEMENT

SECOND RING

OIL RING

TAPER

CUTTER RING WITH COIL EXPANDER

THREE-PIECE CONSTRUCTION

Fig. 4-6

EXHAUST VALVE INTAKE VALVE

This engine has a chain-driven overhead cam and overhead valve construction, with a single cam performing both intake and exhaust oper ations.

4-8 CYLINDER HEAD

The cylinder head is an aluminum die-casting with a pent roof combustion chamber construction. The intak e and exhaust ports are arranged in a cross direction to improve combustion efficiency.

Fig. 4-7

Fig. 4-8

- 9 -

4-9 GOVERNOR SYSTEM

GOVERNOR GEAR

This engine is equipped with a centrifugal flyweight type governor that makes it possible to oper ate the engine at a constant speed, even with load variations. (The governor flyweights are mounted on a governor gear .)

Fig. 4-9

4-10 COOLING SYSTEM

The engine uses a forced air-cooling system in which a cooling fan (which also works as a flywheel) forces cooling air into the cylinder and the cylinder head. Baffles are provided to guide the flow of the cooling air. (Model EX21 is provided with a synthetic resin cooling fan that is separate from the flywheel.)

4-11 LUBRICATION SYSTEM

The rotating parts, sliding parts and valv es of the engine are lubricated with oil in the crankcase. The oil is splashed

onto the parts by the oil splasher on the connecting rod.

4-12 TIMING CHAIN

Timing chain system is adopted and designed for lubricating for the upper portion of cylinder head. The timing chain is engaged between the sprocket portion of integrated camshaft in the cylinder head and the crankshaft gear sprocket. The sprocket teeth in particular shape are adopted to enhance the durability and to realize low noise level.

4-13 IGNITION SYSTEM

The ignition system is a transistor controlled magneto system with the ignition timing set at 23 degrees (EX13/ 17/21)[27 degrees (EX27)] before the top dead center . The magneto consists of a flywheel and ignition coil. The flywheel (which also works as a fan) is directly mounted on the crankshaft and the ignition coil is directly mounted on the crankcase.

TIMING CHAIN

OIL SPLASHE

Fig. 4-10

※Model EX13,17,21 and 27D has a smooth advanced

ignition timing system to improve starting performance. (For further details, refer to page 48, section “7. MAGNET O”.)

IGNITION COIL

FLYWHEEL

Fig. 4-11

4-14 CARBURETOR

The engine is equipped with a horizontal draft carburetor. The carburetor setting is calibrated after careful testing for optimum all-round performance (including starting, acceleration, fuel consumption, output power characteristics). Special attention is also paid to the general-purpose use of the engine. (For further information, refer to page 57, section “11. CARBURETOR”.)

Fig.4-12

4-15 AIR CLEANER

The engine uses an air cleaner that is quieter than conventional ones. A semi-wet urethane foam element is used in the STD air cleaner. Dual element air cleaner (with a primary element of d ry type sponge and secondary element of dry type paper) and other types are also provided as special options.

4-16 BALANCER

(PROVIDED ONLY IN MODEL EX27D)

Unbalanced inertia force is cancelled by the balancer which rotates at the same speed as the crankshaft to effectively reduce vibration.

STD Type Dual Element Type

CLEANER COVER

URETHANE FOAM

Fig.4-13

CLEANER COVER

URETHANE FOAM

PAPER ELEMENT

4-17 DECOMPRESSION SYSTEM

The automatic decompression system is mounted on the camshaft. It opens the exhaust valve before the compression top, thereby alle viating the compression pressure and reducing the force required to pull the recoil starter. During engine operation, the decompression system is overpowered by centrifugal force and compression is fully utilized to produce power .

Fig.4-14

RETURN SPRING

ROCKER ARM (EXHAUST VALVE SIDE)

EXHAUST VALVE

CAMSHAFT

Fig.4-15

4-18 SECTIONAL VIEW OF THE ENGINE

Cross sectional view – across the shaft

FUEL TANK

TANK CAP

GOVERNOR SHAFT

BLOWER HOUSING

STARTING PULLEY

RECOIL STARTER

FLYWHEEL CHARGE COIL

(OPTION)

OIL SENSOR

(OPTION)

GOVERNOR LEVER

GOVERNOR GEAR

CRANKSHAFT

CONNECTING ROD

MAIN BEARING COVER

Fig. 4-16

M S

G G

N R

Cross sectional view – along the shaft

FUEL STRAINER

CHAIN GUIDEGOVERNOR LEVER

FUEL TANK

OVERNOR EAR

AGNETIC

WITCH

TIMING CHAIN

STARTING MOTOR (OPTION)

MUFFLER COVER

EXHAUST

VALVE

MUFFLERPISTON

TAIL SCREE or DEFLECTO (OPTION)

SPARK ARRESTER (OPTION)

ROCKER

ARM

CAMSHAFT

INTAKE VALVE

PISTON PIN

PISTON RING

TENSIONER

OIL GAUGE

OIL DRAIN PLUG

FILLER PLUG

CONNECTING ROD

CRANKSHAFTCRANKCASE

OIL SENSOR

(OPTION)

Fig. 4-17

5. DISASSEMBLY AND REASSEMBLY

5-1 PREPARATIONS AND PRECAUTIONS

(1) When disassembling the engine, memorize the location of each part so that you can reassemble the engine

correctly. If necessary , attach identification tags with the required assembly information to the parts. (2) Store groups of parts in separate box es . This will make reassembly easier. (3) To prevent parts from being mislaid, keep each group provisionally assembled after removing the parts from

the engine. (4) Handle the disassembled parts with the utmost care. Clean them with cleaning oil if necessary . (5) Use the correct tools in the correct wa y when disassemb ling and reassembling the engine.

5-2 SPECIAL TOOLS

Tool name Use

Commercially available product

Flywheel puller For pulling off the flywheel

FLYWHEEL PULLER

Fig. 5-1

5-3 DISASSEMBLY PROCEDURE

Step Parts to remove Remarks and procedures Fasteners

1 Drain the engine oill (1) Remove a drain plug (M14×12mm)

located on both sides of the case. Take care not to lose the gaskets.

(2) To discharge oil quickly, remove the oil

guage.

14 mm spanner

OIL GAUGE

GASKET

STEP 1

GASKET

DRAIN PLUG

Fig. 5-2

Step Parts to remove Remarks and procedures Fasteners

Air cleaner cover Remove the air cleaner cover.

Air cleaner Remove the element, and remove the air

cleaner while pulling the breather pipe away from the rocker cover.

STEP 3

AIR CLEANER COVER

URETHANE FOAM

10 mm box spanner M6 nut: 2 pcs. M6×20:1pc.

DUAL ELEMENT TYPESTD TYPE

STEP 3

AIR CLEANER COVER

URETHAN FOAM

PAPER ELEMENT

M6 x 20 FLANGE BOLT : 1 pc.

Fig. 5-3

AIR CLEANER COVER

STEP 2

BREATHER PIPE

M6 FLANGE NUT : 2 pcs.

Step Parts to remove Remarks and procedures Fasteners

Stop switch Disconnect the wire and remove the stop

switch from the blower housing.

Recoil starter Remove the recoil starter from the blower

Blower housing Baffle 2 (head) Baffle 3

housing.

(1)Remove the blower housing from the

crankcase.

(2)Remove the baffle 2 (head) and baffle 3.

STEP 4

M6 x 12 BOLT : 4 pcs.

M4 TAPPING SCREW : 2 pcs.

STOP SWITCH

10 mm box spanner M6 × 8mm : 4 pcs.

10 mm box spanner M6 × 12mm : 4 pcs. 10 mm box spanner or

spanner M6 × 12mm : 2 pcs. (Baffle 2 (head)) M5 tapping bolt : 2 pcs. (Baffle 3)

M6 x 8 BOLT : 4 pcs.

STEP 5

BAFFLE 3

(EX21 ONLY)

M5 TAPPING BOLT : 2 pcs.

RECOIL STARTER

BLOWER HOUSING

STEP 6

BAFFLE 2 (HEAD)

M6 x 12 BOLT : 1 pc.

STEP 6

Fig. 5-4

Step Parts to remove Remarks and procedures Fasteners

Fuel tank (1) Drain fuel from the carburetor drain.

(2) Remove the fuel tank mounting nuts

and bolts from the crankcase.

(3) Disconnect the fuel pipe from the carburetor.

(See Fig. 5-6)

(4) Remove the fuel tank from the crankcase.

Muffler and Muffler cover (1) Remove the muffler cover from the

muffler.

(2) Remove the muffler from the cylinder

head. Take care not to lose the gasket.

※Take care not to cut your hand with the

muffler gasket.

※Seal the exhaust port with adhesive

tape or plug it with cloth to prevent nuts and other objects from falling inside.

STEP 7

FUEL TANK

10 (12) mm spanner or box

wrench M6 nut : 2 pcs. (Models EX13, 17 and 21) M8 nut : 2 pcs. (Model EX 27) M6 × 25mm : 1 pc. (Models EX 13, 17 and 21) M8 × 25mm : 2 pcs. (Model EX27)

12mm box spanner 10mm box spanner or

spanner M6 tapping bolt : 2 pcs. M6 × 8mm : 1 pc. M8 nut : 2 pcs. M8 × 12mm : 1 pc.

M6 x 10 TAPPING BOLT : 2 pcs.

STEP 8

M6 NUT : 2 pcs. (EX13,17,21) M8 NUT : 2 pcs. (EX27)

FUEL PIPE

M6 x 8 FLANGE BOLT : 1 pc.

M8 NUT : 2 pcs.

M6 x 25 BOLT : 1 pc. (EX13, 17, 21) M8 x 25 BOLT : 2 pcs.

(EX27)

MUFFLER

M8 x 12 BOLT : 1 pc.

GASKET

(It has two faces)

FUEL DRAIN

Seal the exhaust port with adhesive tape or plug it with cloth.

Fig.5-6

Fig.5-5

Step Parts to remove

Remarks and procedures

Fasteners

Governor system (1) Loosen the bolt and remove the governor

lever from the governor shaft. There is no

need to remove the bolt. (2) Remove the governor spring. (3) Remove the governor rod and the rod

spring from the carburetor.

Carburetor, Insulator Remove the carburetor from the cylinder head.

Speed control lever and

Bracket

STEP 9

GOVERNOR LEVER

Remove the insulator.

Remove the speed control lever and bracket from the cylinder head.

GOVERNOR ROD and ROD SPRING

GOVERNOR SPRING

10 mm box spanner or

spanner

M6 × 30mm : 1 pc.

10 mm box spanner M6 × 12mm : 2 pcs.

GOVERNOR SHAFT

M6 x 12 BOLT : 2 pcs.

STEP 11

SPEED CONTROL LEVER and BRACKET

GASKET

INSULATOR

GASKET

CARBURETOR

STEP 10

Fig.5-7

Step Parts to remove Remarks and procedues Fasteners

Ignition coil Remove the spark plug cap from the spark plug and

remove the ignition co il from the crankcase.

Starting pulley Remove the starting pulley from the flywheel.

Fit a box wrench or a socket wrench on the flywheel nut and loosen the nut by knocking the wrench sharply with a hammer. (See Fig. 5-10) NOTE:

1) Do not insert a screwdriver or other objectbetween the flywheel blades, otherwise the risk of damaging the blades might be occured.

2) Knock the w rench with a hammer in a counter

clockwise direction.

3) The fan of the Model EX21 engine is made of

synthetic resin. Take the utmost care when handling it.

Flywheel Remove the flywheel from the crankshaft. Leave the nut

temporarily to prevent the flywheel from dropping out.Fit

the flywheel puller as shown in Figure 5-11 and remove the flywheel from the crankshaft by rotating the bolt at the centerin a clockwise direction. (Knock the center bolt witha hammer sometimes)

10 mm box spanner M6 × 25mm : 2 pcs.

19 (24) mm box spanner o socket wrench M14 nut (Models EX13,17 and 21) M18 nut (Model EX27)

Flywheel pull er

FLYWHEEL PULLER

Fig. 5-10 Fig. 5-11

M14 NUT : 1 pc. (EX13,17,21) M18 NUT : 1 pc. (EX27)

STEP 13

STEP 14

FLYWHEEL

STARTING PULLEY

M6 x 25 BOLT an WASHER : 2 pcs.

STEP 12

GROMMET (EX13,17,21 only)

Fig. 5-9

ATTACH NUT TEMPORARILY

Step Parts to remove Remarks and procedures Fasteners

Electric starter (option)

Control box,

Diode rectifier,

Magnetic switch

STEP 15

(1) Disconnect the grounding cable from battery. (2) Disconnect the wire leading from the key

(3) Disconnect the wire that connects the

(4) Remove the electric starter.

ELECTRIC STARTER (option)

switchSTterm inal to the magnetic switch.

positive terminal of the battery to the magnetic switch.

M6 NUT : 1 pc. (EX17,21) M8 NUT : 1 pc. (EX27)

EX27

M8 x 28 BOLT : 2 pcs.

EX17, 21

UPPER SIDE M6 x 30 FLANGE BOLT : 1 pc DOWN SIDE M6 x 20 FLANGE BOLT : 1 pc

12 mm box spanner

M8 nuts 10 mm box spanner 12 mm box spanner

Fig. 5-8

Step Parts to remove Remarks and procedures Fasteners

Baffle 1 (case) Remove the baffle 1 (case) M6 × 12mm : 1 pc.

(Models EX13, 17 and 21) M8 × 12mm : 1 pc. (Model EX27)

Charge coil (option) Remove the charge coil.

(For EX27, remove the wire clamp together)

box spanner M6 × 20mm : 2 pcs. + screwdriver

Spark plug Remove the spark plug from the cylinder head. 21 mm plug wrench

M6 x 12 FLANGE BOLT : 1 pc. (EX13, 17, 21) M8 x 12 FLANGE BOLT : 1 pc. (EX27)

BAFFLE 1 (CASE)

For the model without electric starter.

STEP 16

STEP 17

CHARGE COIL

SPACER

Fig.5-12

STEP 18

SPARK PLUG

CHARGE COIL

VIEW

EX13

EX17

EX21

EX27

(EX27 only)

15W 40W 15W 40W

200W

15W 40W

200W

15W 40W

200W

CLAMP

SPACER

NA NA NA NA

BOLT M6 x 40L M6 x 35L M6 x 35L M6 x 40L M6 x 25L M6 x 35L M6 x 40L M6 x 25L M6 x 20L M6 x 30L M6 x 25L

Step Parts to remove Remarks and procedures Fasteners

Rocker cover (1) Remove the rocker cover from the

cylinder head.

(2) Remove the gasket (rocker cover).

Rocker arm

Remove the pin (rocker arm) and the rocker

arm from the cylinder head at the compression top dead center.(See Fig. 5-14b)

ROCKER ARM (EXHAUST VALVE SIDE)

PIN (ROCKER ARM)

ROCKER ARM (INTAKE VALVE SIDE)

10 mm box spanner M6 × 12mm : 4 pcs.

The position of compression top dead center

Punch marks

Fig. 5-14a

STEP 20

ROCKER ARM (INTAKE VALVE SIDE)

CLOSE-UP A

GASKET (ROCKER COVER)

Fig. 5-14b

ROCKER ARM (EXHAUST VALVE SIDE)

PIN (ROCKER ARM)

STEP 19

Fig. 5-13

ROCKER COVER

M6 x 12 BOLT : 4 pcs.

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