OPERATION

TOOLS REQUIRED

1.

INSERT 2 SCREWS M8X60 ON BOTTOM OF CRANKCASE TO POSITION MOTOR ON BENCH

-VICE ON BENCH ( TOOL AS PER DRAW. S725/1)

Fig.1

2.

REMOVE EXHAUST PIPE AND EXHAUST GASKET (see Fig.1):

-3 M6 EXHAUST NUTS

-3 WASHERS

– 12 POINT WRENCH – 10mm

Fig.2

Fig.3

3.

REMOVE CLUTCH:

-REMOVE CLUTCH COVER

3 SCREWS M6 (see Fig.2).

REPLACE SPARKPLUG WITH SPECIAL PISTON FITTING (see Fig.3).

ROTATE CRANKSHAFT UP TO TDC SO THAT CRANKSHAFT DOES NOT ROTATE WHEN REMOVING THE 1Omm NUT.

• 5mm ALLEN
• PISTON FITTING: P.N. 10271
• 12 POINT WRENCH 17mm
• CLUTCH WRENCH: P.N. 10270
• 12 POINT 24mm
• 12 POINT WRENCH 19mm
• CLUTCH PULLER: P.N. B-55614-C
• 12 POINT WRENCH 10mm

Fig.4

Fig.5

Fig.6

Fig.7

–REMOVE 10mm NUT

(see Fig.4)

–REMOVE OUTER WASHER , ROLLER CAGE, CLUTCH DRUM AND INNER WASHER.

–REMOVE THE PISTON FITTING AND USING THE CLUTCH WRENCH, REMOVE THE CLUTCH FIXING NUT (see fig.5).

ATTENTION:

TURN CLOCKWISE AS NUT HAS LEFT THREAD.

–REMOVE SAFETY WASHER

APPLY CLUTCH PULLER ON CLUTCH AND REMOVE CLUTCH WITH 19mm SOCKET (see Fig 6).

REMOVE KEY FROM SHAFT SEAT.

–REMOVE THE START RING FROM THE CLUTCH

3 SCREWS M6 (see Fig.7).

Fig.8

Fig.9

4.

Fig.2

– REMOVE THE CARB MANIFOLD

4 SCREWS M6X25

4 WASHERS (see fig. 8)

REMOVE THE REED PACK GASKET -OUTER.

–REMOVE THE REED PACK

(see Fig. 9)

–REMOVE THE REED PACK GASKET – INNER

– 4mm ALLEN

Fig.10

Fig.11

5.

REMOVE THE IGNITION:

–REMOVE THE IGNITION COVER

3 SCREWS M6X18 (see Fig.10)

–REMOVE STATOR

4 SCREWS M5X25 (see Fig.11)

–INSTALL THE PISTON FITTING AND REMOVE SELF LOCKING NUT M8 WITH KNURLED WASHER.

• 4mm ALLEN
• 5mm ALLEN
• 13mm HEXAGON RING WRENCH
• PISTON FITTING: P.N. 10271

Fig.12

–REMOVE ROTOR (see Fig.12)

Fig.13

Fig.14

6.

-UNLOOSE THE SCREW M6X30 ON THE STARTER SUPPORT

(see Fig.13)

– REMOVE THE STARTER SUPPORT

3 SCREWS M6X25 (see Fig.14)

– 5mm ALLEN

Fig.15

7.

– REMOVE THE STARTER ASSEMBLY

4 SCREWS M6X45 (see Fig.15)

– 5mm ALLEN

Fig.16

Fig.18

Fig.19

Fig.17

–REMOVE STARTER FROM SUPPORT

3 SCREWS M6X35 (see Fig.16/17).

– REMOVE THE COUNTERSHAFT SUPPORT COVER

3 SCREWS M6X25 (see Fig.18).

– EXTRACT THE COUNTERSHAFT FROM THE SUPPORT

(see Fig.19).

8.

REMOVE THE HEAD:

-LOOSEN NUTS BY ½ TURN (CROSS PATTERN DISASSEMBLY) AND THEN REMOVE:

4 NUTS M8

4 WASHERS

4 O-RINGS Ø7.65mm ON STUDS

1 O-RING Ø60mm HEAD INTERNAL DIAM.

1 O-RING Ø123.5mm HEAD EXTERNAL DIAM

– 13mm SOCKET T TYPE

Fig.20

9.

REMOVE CYLINDER (see Fig.20).

10.

REMOVE CYLINDER GASKET.

Fig.21

11.

REMOVE CIRCLIPS FROM PISTON (see Fig.21)

ATTENTION:

DO NOT SCRATCH PISTON OR CIRCLIP SEATS.

-SCREWDRIVER WITH ROUNDED EDGES

Fig.22

12.

REMOVE PISTON PIN, PISTON AND CAGE USING THE PISTON PIN PUNCH (see Fig. 22).

PISTON PIN PUNCH P.N. 10200

Fig.23

Fig.24

Fig.25

13.

OPENING THE CRANKCASE:

–REMOVE 7 FIXING SCREWS

(see Fig.23)

4 SCREWS M6X40

3 SCREWS M6X50

–OPEN THE CRANKCASE (USING A PLASTIC MALLET)

AVOID CRANKSHAFT FROM FALLING.

– REMOVE OIL SEALS, USE A SCREWDRIVER (see Fig.24)

–REMOVE BEARINGS (if necessary)

HEAT HALFCRANKCASES AT 70°

OR USE PRESS AND SPECIAL

PUSHER AS PER DRAW. S725/1 (see Fig.25)

–REMOVE SHIMS

• 5mm ALLEN
• PLASTIC MALLET

14.

OPEN CRANKSHAFT ONLY WITH SPECIAL TOOL.

ATTENTION:

THIS OPERATION CAN BE PERFORMED ONLY BY AN AUTHORIZED SERVICE CENTER.