Piaggio Vespa WORKSHOP LX 125 150 4tempi Workshop Manual

WORKSHOP MANUAL

633432

LX 125 - 150 4tempi

WORKSHOP

MANUAL

LX 125 - 150 4tempi

The descriptions and illustrations given in this publication are not binding. While the basic specifications
as described and illustrated in this manual remain unchanged, PIAGGIO-GILERA reserves the right, at

any time and without being required to update this publication beforehand, to make any changes to

components, parts or accessories, which it considers necessary to improve the product or which are

required for manufacturing or construction reasons.

Not all versions/models shown in this publication are available in all countries. The availability of single

versions should be checked at the official Piaggio sales network.

"© Copyright 2007 - PIAGGIO & C. S.p.A. Pontedera. All rights reserved. Reproduction of this publication

in whole or in part is prohibited."

PIAGGIO & C. S.p.A. - After-Sales

V.le Rinaldo Piaggio, 23 - 56025 PONTEDERA (Pi)

WORKSHOP MANUAL

LX 125 - 150 4tempi

This workshop manual has been drawn up by Piaggio & C. Spa to be used by the workshops of Piaggio­Gilera dealers. This manual is addressed to Piaggio service mechanics who are supposed to have a
basic knowledge of mechanics principles and of vehicle fixing techniques and procedures. Any important
changes made to the vehicles or to specific fixing operations will be promptly reported by updates to this
manual. Nevertheless, no fixing work can be satisfactory if the necessary equipment and tools are
unavailable. It is therefore advisable to read the sections of this manual relating to specific tools, along
with the specific tool catalogue.

N.B. Provides key information to make the procedure easier to understand and carry out.

CAUTION Refers to specific procedures to carry out for preventing damages to the vehicle.

WARNING Refers to specific procedures to carry out to prevent injuries to the repairer.

Personal safety Failure to completely observe these instructions will result in serious risk of personal

injury.

Safeguarding the environment Sections marked with this symbol indicate the correct use of the vehicle
to prevent damaging the environment.

Vehicle intactness The incomplete or non-observance of these regulations leads to the risk of serious
damage to the vehicle and sometimes even the invalidity of the guarantee.

INDEX OF TOPICS

CHARACTERISTICS CHAR

TOOLING TOOL

MAINTENANCE MAIN

TROUBLESHOOTING TROUBL

ELECTRICAL SYSTEM ELE SYS

ENGINE FROM VEHICLE ENG VE

ENGINE ENG

SUSPENSIONS SUSP

BRAKING SYSTEM BRAK SYS

CHASSIS CHAS

PRE-DELIVERY PRE DE

TIME TIME

INDEX OF TOPICS

CHARACTERISTICS CHAR

LX 125 - 150 4tempi Characteristics

Rules

This section describes general safety rules for any maintenance operations performed on the vehicle.

Safety rules

- If work can only be done on the vehicle with the engine running, make sure that the premises are well­ventilated, using special extractors if necessary; never let the engine run in an enclosed area. Exhaust
fumes are toxic.

- The battery electrolyte contains sulphuric acid. Protect your eyes, clothes and skin. Sulphuric acid is
highly corrosive; in the event of contact with your eyes or skin, rinse thoroughly with abundant water
and seek immediate medical attention.

- The battery produces hydrogen, a gas that can be highly explosive. Do not smoke and avoid sparks
or flames near the battery, especially when charging it.

- Fuel is highly flammable and it can be explosive given some conditions. Do not smoke in the working
area, and avoid naked flames or sparks.

- Clean the brake pads in a well-ventilated area, directing the jet of compressed air in such a way that
you do not breathe in the dust produced by the wear of the friction material. Even though the latter
contains no asbestos, inhaling dust is harmful.

Maintenance rules

- Use original PIAGGIO spare parts and lubricants recommended by the Manufacturer. Non-original or
non-conforming spares may damage the vehicle.

- Use only the appropriate tools designed for this vehicle.

- Always use new gaskets, sealing rings and split pins upon refitting.

- After removal, clean the components using non-flammable or low flash-point solvents. Lubricate all
the work surfaces, except tapered couplings, before refitting these parts.

- After refitting, make sure that all the components have been installed correctly and work properly.

- For removal, overhaul and refit operations use only tools with metric measures. Metric bolts, nuts and
screws are not interchangeable with coupling members with English sizes. Using unsuitable coupling
members and tools may damage the scooter.

- When carrying out maintenance operations on the vehicle that involve the electrical system, make
sure the electric connections have been made properly, particularly the ground and battery connections.

CHAR - 7

Characteristics LX 125 - 150 4tempi

Vehicle identification

VEHICLE IDENTIFICATION

Specification Desc./Quantity

Chassis prefix (125) ZAPM44100 ÷ 1001

Engine prefix (125) MXXXM ÷ 1001

Chassis prefix (150) ZAPM44200 ÷ 1001

Engine prefix (150) MXXXM ÷ 1001

Dimensions and mass

Specification

Curbside weight 110 ± 5 kg
Maximum height 1140 mm

Width 740 mm

Wheelbase 1280 mm

Length 1800 mm

DIMENSIONS AND WEIGHT

Desc./Quantity

CHAR - 8

LX 125 - 150 4tempi Characteristics

Engine

Compression ratio (125) 10.6 : 1

Maximum power to crankshaft (125) 10.5 CV at 8000 rpm

Transmission

ENGINE

Specification

Engine Single-cylinder, 4-stroke Piaggio LEADER

Timing system Single overhead camshaft (SOHC) with 2 valves

Valve clearance intake 0.10

Bore x stroke (125) 57 x 48.6 mm

Bore x stroke 62,6 x 48.6 mm

Cubic capacity (125) 124 cm³

Cubic capacity 150,46 cm³

Compression ratio 10.5: 1

Carburettor KEIHIN CVEK26

Engine idle speed approx. 1600 ÷ 1800 rpm

Start-up Electric

Max. power 11.6 hp at 7750 rpm

Cooling Forced air circulation.

TRANSMISSION

Specification

Transmission With automatic expandable pulley variator with torque server,

V belt, automatic clutch, gear reduction unit and transmission

housing with forced air circulation cooling.

Desc./Quantity

outlet 0.15

Desc./Quantity

CHAR - 9

Characteristics LX 125 - 150 4tempi

Capacities

CAPACITY

Specification Desc./Quantity

Engine oil 61 in³ (1,000 cm³)

Rear hub oil ~ 100 cm³

Fuel tank capacity ~ 8.5 litres (2 l of which is reserve)

Electrical system

ELECTRICS

Specification Desc./Quantity

Start-up Electric

Spark plug (125) Champion RG6YC- NGK CR7EB

Spark plug Champion RG6YC- NGK CR7EB

Frame and suspensions

Specification

Steering and suspensions Steering tube articulated on the front wheel carrier hub; heli-

Brakes

Specification

Front brake Disc brake (Ø 200 mm) with hydraulic control (lever on the far
Rear brake Ø110 mm drum brake

Wheels and tyres

Specification

Front wheel rim Die-cast aluminium alloy; 2.50 x11"

Front tyre Tubeless; 110/70-11"

Rear wheel rim Die-cast aluminium alloy; 3.00 x 10"

Rear tyre Tubeless; 120/70-10"
Front tyre pressure 1.6 bar
Rear tyre pressure 2 bar

Rear wheel pressure (rider and passenger): 2.3 bar

FRAME AND SUSPENSIONS

Desc./Quantity

Chassis Unitised body made of stamped plate.

coidal spring suspension and double-acting hydraulic shock

absorber; rear with double-acting shock absorber and coaxial

spring adjustable to 4 positions at preloading.

BRAKES

Desc./Quantity

right of the handlebar) and fixed calliper.

WHEELS AND TYRES

Desc./Quantity

CHAR - 10

LX 125 - 150 4tempi Characteristics

Secondary air

In order to reduce polluting emissions, the vehicle
is furnished with a catalytic converter in the muf­fler.
To favour the catalytic process, an extra amount
of oxygen is added via a secondary air system
(SAS).
This system allows more oxygen to be added to
the unburned gases before they reach the con­verter, thus improving the action of the catalytic
converter.
The air enters the exhaust duct from the head, and
is purified by a black filter.
The system is fitted with a control valve that disa­bles operation while decelerating to avoid unwan­ted noise.
To ensure the best functioning of the SAS system,
every 12,000 km the scooter should be taken to an
Authorised Piaggio Service Centre to have the
filter cleaned (Scheduled maintenance operations
section).
The filter sponge should be cleaned with water and
mild soap, then it should be dried with a cloth and
slight blows of compressed air.

CAUTION

CONTACT AN AUTHORISED PIAGGIO SERVICE CENTRE
TO CARRY OUT THESE OPERATIONS.

Carburettor

125cc Version

Kehin

Throttle valve diameter Ø 26.5

CARBURETTOR SETTING

Specification

Type CVEK26

Desc./Quantity

CHAR - 11

Characteristics LX 125 - 150 4tempi

Specification Desc./Quantity

Diffuser diameter Ø 26.4

Setting stamping 262A

Maximum jet 82

Maximum air jet (on the body) 85

Tapered pin stamping NELA

Throttle valve spring 130 ÷ 180 gr.

Minimum jet 35

Idle air jet (on the body) 150

Idle mixture adjustment screw initial opening 1 ¾

Starter jet 42

Starter air jet (on the body) Ø 1.5

Starter pin travel 10 mm (at 24°)

Starter resistance 20 Ohm (at 24°)

150cc Version

Kehin

CARBURETTOR SETTING

Specification Desc./Quantity

Type CVEK26

Throttle valve diameter Ø 26.5

Diffuser diameter Ø 26.4

Setting stamping 265A

Maximum jet 82

Maximum air jet (on the body) 85

Tapered pin stamping NELA

Throttle valve spring 130 ÷ 180 gr.

Minimum jet 35

Idle air jet (on the body) 150

Idle mixture adjustment screw initial opening 1 ¾

Starter air jet (on the body) Ø 1.5

Starter jet 42

Starter pin travel 10 mm (at 24°)

Starter resistance 20 Ohm (at 24°)

Tightening Torques

Name

Hub oil drainage cap 15 ÷ 17

Oil filter 4 ÷ 6

Oil pump cover screws 5 - 6

Oil pump screws 5 - 6

Pump control pulley screw 10 ÷ 14

Chain cover screws 4 ÷ 6

Oil sump screws 10 ÷ 14

Minimum oil pressure sensor 12 ÷ 14

Blow-by recovery duct fixing screws 3 - 4

Name

Ignition spark plug 12 ÷ 14

Head cover screws 11 ÷ 13

Nuts fixing head to cylinder (*) 28 ÷ 30

Head fixing screws (external) 11 ÷ 13

Starter ground screw 7 ÷ 8.5

Flywheel cover screw 1 ÷ 2

CHAR - 12

LUBRICATION

Torque in Nm

HEAD AND CYLINDER

Torque in Nm

LX 125 - 150 4tempi Characteristics

Name Torque in Nm

Flywheel air manifold screw 3 ÷ 4

Pressure reducer counterweight retainer 7 ÷ 8.5

Camshaft pulley screw 12 ÷ 14

Timing chain tensioner slider screw 10 ÷ 14

Starter ground support screw 11 ÷ 15

Tensioner screws 11 ÷ 13

Timing chain tensioner central screw 5 - 6

Camshaft retention plate screw 5 - 6

Nut fixing muffler to cylinder head 16 ÷ 18

Head intake manifold screw 11 ÷ 13

TRANSMISSION

Name Torque in Nm

Drive pulley nut 75 ÷ 83

Transmission cover screw 11 ÷ 13

Driven pulley shaft nut 54 ÷ 60

Rear hub cap screw 24 ÷ 27

Clutch unit nut on driven pulley 45 ÷ 50

FLYWHEEL

Name Torque in Nm

Flywheel fan screws 3 ÷ 4

Stator assembly screws (°) 3 ÷ 4

Flywheel nut 52 ÷ 58

Pick-up screw 3 ÷ 4

(°) Apply LOCTITE 243 threadlock

CRANKCASE AND CRANKSHAFT

Name

Internal engine crankcase bulkhead (transmission-side half

shaft) screws

Oil filter on crankcase fitting 27 ÷ 33

Rear brake cam tightening screw 11 ÷ 13

Engine-crankcase coupling screws 11 ÷ 13

Pre-filter cap 24 ÷ 30

Starter motor fixing screw 11 ÷ 13

Muffler to crankcase fixing screws 24 ÷ 27

Engine oil drainage cap 24 ÷ 30

STEERING ASSEMBLY

Name

Steering upper ring nut 35 ÷ 40
Lower steering ring nut 12 - 14
Handlebar fixing screw 50 ÷ 55

FRAME ASSEMBLY

Name

Swinging arm pin - frame 44 ÷ 52

Engine-swinging arm bolt 33 ÷ 41

Stand bolt 32 ÷ 40

Swinging arm silent-block containment bolt 33 ÷ 41

FRONT SUSPENSION

Name

Shock absorber upper nut 20 ÷ 30

Front wheel axle nut 75 ÷ 90

Shock absorber upper bracket bolts 20 ÷ 25

Wheel rim screws 20 ÷ 25

Shock absorber lower bolts (°) 20 ÷ 27

Torque in Nm

4 ÷ 6

Torque in Nm

Torque in Nm

Torque in Nm

CHAR - 13

Characteristics LX 125 - 150 4tempi

FRONT BRAKE

Name Torque in Nm

Brake fluid pump-hose fitting 8 ÷ 12

Brake fluid pipe-calliper fitting 20 ÷ 25

Screw tightening calliper to the support 20 ÷ 25

Brake disc screw 5 ÷ 6.5

Oil bleed valve (on the calliper) 10 ÷ 12

Handlebar pump 7 ÷ 10

REAR SUSPENSION

Name Torque in Nm

Rear wheel axle 104 ÷ 126

Lower shock absorber clamp 33 ÷ 41

Shock absorber/frame nut: 20 ÷ 25

Overhaul data

Assembly clearances

Cylinder - piston assy.

Versione 150

COUPLING BETWEEN (AXIS-WERKE) PISTON AND CYLINDER (150)

Name

Coupling A 62.580 ÷ 62.587 62.533 ÷ 62.540 0.040 ÷ 0.054
Coupling B 62.587 ÷ 62.594 62.540 ÷ 62.547 0.040 ÷ 0.054
Coupling C 62.594 ÷ 62.601 62.547 ÷ 62.554 0.040 ÷ 0.054
Coupling D 62.601 ÷ 62.608 62.554 ÷ 62.561 0.040 ÷ 0.054

Coupling 1st oversize A1 62.780 ÷ 62.787 62.733 ÷ 62.740 0.040 ÷ 0.054

coupling 1st oversize B1 62.787 ÷ 62.794 62.740 ÷ 62.747 0.040 ÷ 0.054
Coupling 1st oversize C1 62.794 ÷ 62.801 62.747 ÷ 62.754 0.040 ÷ 0.054
Coupling 1st oversize D1 62.801 ÷ 62.808 62.754 ÷ 62.761 0.040 ÷ 0.054

Coupling 2nd oversize A2 62.980 ÷ 62.987 62.933 ÷ 62.940 0.040 ÷ 0.054
Coupling 2nd oversize B2 62.987 ÷ 62.994 62.940 ÷ 62.947 0.040 ÷ 0.054
Coupling 2nd oversize C2 62.994 ÷ 63.001 62.947 ÷ 62.954 0.040 ÷ 0.054
Coupling 2nd oversize D2 63.001 ÷ 63.008 62.954 ÷ 62.961 0.040 ÷ 0.054
Coupling 3rd oversize A3 63.180 ÷ 63.187 63.133 ÷ 63.140 0.040 ÷ 0.054
Coupling 3rd oversize B3 63.187 ÷ 63.194 63.140 ÷ 63.147 0.040 ÷ 0.054
Coupling 3rd oversize C3 63.194 ÷ 63.201 63.147 ÷ 63.154 0.040 ÷ 0.054
Coupling 3rd oversize D3 63.201 ÷ 63.208 63.154 ÷ 63.161 0.040 ÷ 0.054

COUPLING BETWEEN (RIGHT WAY) PISTON AND CYLINDER (150)

Name

Coupling A 62.580 ÷ 62.587 62.541 ÷ 62.548 0.032 ÷ 0.046
Coupling B 62.587 ÷ 62.594 62.548 ÷ 62.555 0.032 ÷ 0.046
Coupling C 62.594 ÷ 62.601 62.555 ÷ 62.562 0.032 ÷ 0.046
Coupling D 62.601 ÷ 62.608 62.562 ÷ 62.569 0.032 ÷ 0.046

Initials Cylinder Piston Play on fitting

Initials Cylinder Piston Play on fitting

Versione 125

CHAR - 14

LX 125 - 150 4tempi Characteristics

COUPLING BETWEEN PISTON AND ALUMINIUM CYLINDER WITH CAST IRON LINER

(125)

Name Initials Cylinder Piston Play on fitting

Coupling A 56.980 ÷ 56.987 56.933 ÷ 56.940 0.040 - 0.054
Coupling B 56.987 ÷ 56.994 56.940 ÷ 56.947 0.040 - 0.054
Coupling C 56.994 ÷ 57.001 56.947 ÷ 56.954 0.040 - 0.054

Coupling D 57.001 ÷ 57.008 56.954 ÷ 56.961 0.040 - 0.054
Coupling 1st increase A1 57.180 ÷ 57.187 57.133 ÷ 57.140 0.040 - 0.054
Coupling 1st increase B1 57.187 ÷ 57.194 57.140 ÷ 57.147 0.040 - 0.054
Coupling 1st increase C1 57.194 ÷ 57.201 57.147 ÷ 57.154 0.040 - 0.054
Coupling 1st increase D1 57.201 ÷ 57.208 57.154 ÷ 57.161 0.040 - 0.054

Coupling 2nd increase A2 57.380 ÷ 57.387 57.333 ÷ 57.340 0.040 - 0.054
Coupling 2nd increase B2 57.387 ÷ 57.394 57.340 ÷ 57.347 0.040 - 0.054
Coupling 2nd increase C2 57.394 ÷ 57.401 57.347 ÷ 57.354 0.040 - 0.054
Coupling 2nd increase D2 57.401 ÷ 57.408 57.354 ÷ 57.361 0.040 - 0.054

Coupling 3rd oversize A3 57.580 ÷ 57.587 57.533 ÷ 57.540 0.040 - 0.054
Coupling 3rd oversize B3 57.587 ÷ 57.594 57.540 ÷ 57.547 0.040 - 0.054
Coupling 3rd oversize C3 57.594 ÷ 57.601 57.547 ÷ 57.554 0.040 - 0.054
Coupling 3rd oversize D3 57.601 ÷ 57.608 57.554 ÷ 57.561 0.040 - 0.054

PISTON TO CAST IRON CYLINDER COUPLING (125)

Name Initials Cylinder Piston Play on fitting

Coupling M 56.997 ÷ 57.004 56.944 ÷ 56.951 0.046 ÷ 0.060

Coupling N 57.004 ÷ 57.011 56.951 ÷ 56.958 0.046 ÷ 0.060

Coupling O 57.011 ÷ 57.018 56.958 ÷ 56.965 0.046 ÷ 0.060

Coupling P 57.018 ÷ 57.025 56.965 ÷ 56.972 0.046 ÷ 0.060
Coupling 1st oversize M1 57.197 ÷ 57.204 57.144 ÷ 57.151 0.046 ÷ 0.060
Coupling 1st oversize N1 57.204 ÷ 57.211 57.151 ÷ 57.158 0.046 ÷ 0.060
Coupling 1st oversize O1 57.211 ÷ 57.218 57.158 ÷ 57.165 0.046 ÷ 0.060
Coupling 1st oversize P1 57.218 ÷ 57.225 57.165 ÷ 57.172 0.046 ÷ 0.060

Coupling 2nd oversize M2 57.397 ÷ 57.404 57.344 ÷ 57.351 0.046 ÷ 0.060
Coupling 2nd oversize N2 57.404 ÷ 57.411 57.351 ÷ 57.358 0.046 ÷ 0.060
Coupling 2nd oversize O2 57.411 ÷ 57.418 57.358 ÷ 57.365 0.046 ÷ 0.060
Coupling 2nd oversize P2 57.418 ÷ 57.425 57.365 ÷ 57.372 0.046 ÷ 0.060

Coupling 3rd oversize M3 57.597 ÷ 57.604 57.544 ÷ 57.551 0.046 ÷ 0.060
Coupling 3rd oversize N3 57.604 ÷ 57.611 57.551 ÷ 57.558 0.046 ÷ 0.060
Coupling 3rd oversize O3 57.611 ÷ 57.618 57.558 ÷ 57.565 0.046 ÷ 0.060
Coupling 3rd oversize P3 57.618 ÷ 57.625 57.565 ÷ 57.572 0.046 ÷ 0.060

Piston rings

SEALING RINGS (125)

Name

Compression ring 57 x 1 A 0.15 ÷ 0.30

Oil scraper ring 57x1 A 0.10 ÷ 0.30
Oil scraper ring 57x2.5 A 0.10 ÷ 0.35

Compression ring 1st

oversize

Oil scraper ring 1st

oversize

Oil scraper ring 1st

oversize

Compression ring 2nd

oversize

Oil scraper ring 2nd

oversize

Oil scraper ring 2nd

oversize

Compression ring 3rd

oversize

Oil scraper ring 3rd

oversize

Description Dimensions Initials Quantity

57.2 x 1 A 0.15 ÷ 0.30

57.2x1 A 0.10 ÷ 0.30

57.2x2.5 A 0.10 ÷ 0.35

57.4x1 A 0.15 ÷ 0.30

57.4x1 A 0.10 ÷ 0.30

57.4x2.5 A 0.10 ÷ 0.35

57.6x1 A 0.15 ÷ 0.30

57.6x1 A 0.10 ÷ 0.30

CHAR - 15

Characteristics LX 125 - 150 4tempi

Name Description Dimensions Initials Quantity

Oil scraper ring 3rd

oversize

Maximum clearance after use: 1 mm

57.6x2.5 A 0.10 ÷ 0.35

SEALING RINGS (150)

Name Description Dimensions Initials Quantity

Compression ring 62.6x1 A 0.15 ÷ 0.30

Oil scraper ring 62.6x1 A 0.20 ÷ 0.40
Oil scraper ring 62.6x2.5 A 0.20 ÷ 0.40

Compression ring 1st

oversize

Oil scraper ring 1st

oversize

Oil scraper ring 1st

oversize

Compression ring 2nd

oversize

Oil scraper ring 2nd

oversize

Oil scraper ring 2nd

oversize

Compression ring 3rd

oversize

Oil scraper ring 3rd

oversize

Oil scraper ring 3rd

oversize

62.8x1 A 0.15 ÷ 0.30

62.8x1 A 0.20 ÷ 0.40

62.8x2.5 A 0.20 ÷ 0.40

63.0 x 1 A 0.15 ÷ 0.30

63.0 x 1 A 0.20 ÷ 0.40

63.0 x 2.5 A 0.20 ÷ 0.40

63.2 x 1 A 0.15 ÷ 0.30

63.2 x 1 A 0.20 ÷ 0.40

63.2 x 2.5 A 0.20 ÷ 0.40

Crankcase - crankshaft - connecting rod

AXIAL CLEARANCE BETWEEN CRANKSHAFT AND CONNECTING ROD

Name

Half-shaft, transmission

side
Flywheel-side half-shaft 16.6 +0-0.05 B D = 0.20 - 0.50
Connecting rod with PP 18 -0.10 -0.15 C 0.20 ÷ 0.50

Crank pin width 51.400 E

AXIAL CLEARANCE BETWEEN CRANKSHAFT AND CRANKSHAFT HALF-BEARINGS

Name

Crankshaft Category 1 28.998 ÷ 29.004
Crankshaft Class 2 29.004 ÷ 29.010
Crankcase Category 1 32.953 ÷ 32.959

Crankcase Category 2 32.959 ÷ 32.965
Crankshaft half-bearing Category B - blue 1.973 ÷ 1.976
Crankshaft half-bearing Type C - yellow 1.976 ÷ 1.979
Crankshaft half-bearing Category E - green 1.979 ÷ 1.982

CHAR - 16

Description Dimensions Initials Quantity

16.6 +0-0.05 A D = 0.20 - 0.50

Description Dimensions Initials Quantity

LX 125 - 150 4tempi Characteristics

Name Description Dimensions Initials Quantity

Crankshaft category 1 -

Crankcase category 1

Crankshaft category 1 -

Crankcase category 2

Crankshaft category 2 -

Crankcase category 1

Crankshaft category 2 -

Crankcase category 2

Crankshaft/crankcase axial clearance: 0.15 ÷ 0.40

E - E
C - C
C - C
B - B

Slot packing system

- Provisionally fit the piston into the cylinder, without any base gasket.

- Fit a dial gauge on the specific tool

- Set the dial gauge to zero at a contrast plane with an average precharge, for example 5 mm. Keeping
the zero setting position, fit the tool on the cylinder and lock it with 2 nuts, as shown in the figure.

- Rotate the crankshaft until TDC (the inverted point of the dial gauge rotation)

- Calculate the difference between the two measurements: use the chart below to identify the thickness
of the cylinder base gasket to be used for refitting. By correctly identifying the cylinder base gasket
thickness, an adequate compression ratio is maintained.

- Remove the specific tool and the cylinder.

Characteristic

Compression ratio (125)

10.6 : 1

Compression ratio

10.5: 1

CHAR - 17

Characteristics LX 125 - 150 4tempi

SHIMMING SYSTEM (125)

Specification Desc./Quantity

Value measured 0 ÷ 0.1

Thickness 0.8 ± 0.05

Value measured 0.1 ÷ 0.3

Thickness 0.6 ± 0.05

Value measured 0.3 - 0.4

Thickness 0.4 ± 0.05

SHIMMING SYSTEM (150)

Specification Desc./Quantity

Value measured 1 ÷ 1.1

Thickness 0.8 ± 0.05

Value measured 1.1 ÷ 1.3

Thickness 0.6 ± 0.05

Value measured 1.3 ÷ 1.4

Thickness 0.4 ± 0.05

Products

AGIP ROTRA 80W-90 rear oil hub SAE 80W/90 Oil that exceeds the re­AGIP CITY HI TEC 4T Oil to lubricate flexible transmissions

AGIP FILTER OIL Oil for air filter sponge Mineral oil with specific additives for in-

AGIP CITY HI TEC 4T Engine oil SAE 5W-40, API SL, ACEA A3, JASO MA

AGIP GREASE MU3 Grease for odometer transmission gear

TABLE OF RECOMMENDED PRODUCTS

Product

(brakes, throttle control and odometer)

AGIP GP 330 Grease (brake control levers, throttle

Description Specifications

grip)

case

quirements of API GL3 specifications

Oil for 4-stroke engines

creased adhesiveness

Calcium complex soap-based grease

with NLGI 2; ISO-L-XBCIB2

Synthetic oil

Soap-based lithium grease with NLGI 3;

ISO-L-XBCHA3, DIN K3K-20

CHAR - 18

INDEX OF TOPICS

TOOLING TOOL

Tooling LX 125 - 150 4tempi

TOOLS

Stores code Description

001330Y Tool for fitting steering seats

001467Y009 Driver for OD 42-mm bearings

001467Y013 Pliers to extract ø 15-mm bearings

002465Y Pliers for circlips

005095Y Engine support

008564Y Flywheel extractor

TOOL - 20

LX 125 - 150 4tempi Tooling

Stores code Description

020004Y Punch for removing fifth wheels from

020055Y Wrench for steering tube ring nut

headstock

020074Y Support base for checking crankshaft

020150Y Air heater support

020151Y Air heater

020193Y Oil pressure gauge

alignment

TOOL - 21

Tooling LX 125 - 150 4tempi

Stores code Description

020262Y Crankcase splitting strip

020263Y Sheath for driven pulley fitting

020287Y Clamp to assemble piston on cylinder

020306Y Punch for assembling valve seal rings

020329Y MityVac vacuum-operated pump

020330Y Stroboscopic light to check timing

TOOL - 22

LX 125 - 150 4tempi Tooling

Stores code Description

020331Y Digital multimeter

020332Y Digital rev counter

020333Y Single battery charger

020334Y Multiple battery charger

TOOL - 23

Tooling LX 125 - 150 4tempi

Stores code Description

020335Y Magnetic support for dial gauge

020357Y 32 x 35 mm adaptor
020359Y 42x47-mm adaptor

020360Y Adaptor 52 x 55 mm

020363Y 20 mm guide

020364Y 25-mm guide

TOOL - 24

LX 125 - 150 4tempi Tooling

Stores code Description

020368Y driving pulley lock wrench

020375Y Adaptor 28 x 30 mm

020376Y Adaptor handle

020382Y011 adapter for valve removal tool

020409Y Multimeter adaptor - Peak voltage detec-

tion

TOOL - 25

Tooling LX 125 - 150 4tempi

Stores code Description

020412Y 15 mm guide

020414Y 28-mm guide

020423Y driven pulley lock wrench

020424Y Driven pulley roller casing fitting punch

020425Y Punch for flywheel-side oil seal

020426Y Piston fitting fork

TOOL - 26

LX 125 - 150 4tempi Tooling

Stores code Description

020427Y Piston fitting band

020428Y Piston position check support

020430Y Pin lock fitting tool

020431Y Valve oil seal extractor

020434Y Oil pressure control fitting

020444Y Tool for fitting/ removing the driven pulley

clutch

TOOL - 27

Tooling LX 125 - 150 4tempi

Stores code Description

020565Y Flywheel lock calliper spanner

020622Y Transmission-side oil guard punch

494929Y Exhaust fumes analyser

020625Y Kit for sampling gas from the exhaust

manifold

TOOL - 28

INDEX OF TOPICS

MAINTENANCE MAIN

Maintenance LX 125 - 150 4tempi

Maintenance chart

EVERY 2 YEARS

Action

Brake fluid - change

EVERY 3000 KM

Action

Engine oil - level check/ top-up

AFTER 1000 KM

80'

Action

Engine oil - replacement
Hub oil - change
Oil filter (net filter) - clean
Idle speed (*) - adjustment
Throttle lever - adjustment
Steering - adjustment
Brake control levers - greasing
Brake pads - check condition and wear
Brake fluid level - check
Safety locks - check
Electrical system and battery - check
Tyre pressure and wear - check
Vehicle and brake test - road test

(*) See instructions in the «Idle speed adjustment» section

AT 6000 KM OR 12 MONTH, 18000 KM, 54000 KM

150'

Engine oil - replacement
Hub oil level - check
Spark plug electrode gap - check
Air filter - clean
Engine oil - change
Oil filter (net filter) - clean
Valve clearance - adjustment
Variable speed rollers/pads - check
Driving belt - checking
Brake pads - check condition and wear
Brake fluid level - check
Electrical system and battery - check
Centre stand - lubrication
Tyre pressure and wear - check
Vehicle and brake test - road test

AT 12000 KM OR 24 MONTHS AND AT 60000 KM

160'

Engine oil - replacement
Hub oil level - check
Air filter - clean
Engine oil - change
Oil filter (net filter) - clean
Spark plug - replacement
Idle speed (*) - adjustment
Throttle lever - adjustment
Pads and variator rollers - replacement

Action

Action

MAIN - 30

LX 125 - 150 4tempi Maintenance

Action

Driving belt - replacement
Odometer gear - greasing
Steering - adjustment
Brake control levers - greasing
Brake pads - check condition and wear
Brake fluid level - check
Transmission elements - lubrication
Safety locks - check
Suspensions - check
Electrical system and battery - check
Headlight - adjustment
Centre stand - lubrication
Secondary air filter - cleaning
Tyre pressure and wear - check
Vehicle and brake test - road test

(*) See section «Adjusting the idle speed»

AFTER 24000 KM AND AFTER 48000 KM

205'

Action

Engine oil - replacement
Hub oil - change
Air filter - clean
Engine oil - change
Oil filter (net filter) - clean
Spark plug - replacement
Idle speed (*) - adjustment
Throttle lever - adjustment
Pads and variator rollers - replacement
Driving belt - replacement
Cylinder ventilation system - cleaning
Odometer gear - greasing
Steering - adjustment
Brake control levers - greasing
Brake pads - check condition and wear
Brake fluid level - check
Transmission elements - lubrication
Safety locks - check
Suspensions - check
Electrical system and battery - check
Headlight - adjustment
Tyre pressure and wear - check
Secondary air filter - cleaning
Centre stand - lubrication
Vehicle and brake test - road test

(*) See instructions in «Idle speed adjustment» section

AT 30000 KM, AT 42000 KM AND AT 66000 KM

125'

Engine oil - replacement
Hub oil level - check
Spark plug electrode gap - check
Air filter - clean
Engine oil - change
Oil filter (net filter) - clean
Slide pads and variator rollers - check
Driving belt - checking
Brake pads - check condition and wear
Brake fluid level - check
Electrical system and battery - check
Centre stand - lubrication
Tyre pressure and wear - check
Vehicle and brake test - road test

Action

MAIN - 31

Maintenance LX 125 - 150 4tempi

AFTER 36000 KM

300'

Action

Engine oil - replacement
Hub oil - change
Spark plug - replacement
Air filter - clean
Engine oil - change
Oil filter (net filter) - clean
Valve clearance - adjustment
Idle speed (*) - adjustment
Throttle lever - adjustment
Pads and variator rollers - replacement
Driving belt - replacement
Odometer gear - greasing
Steering - adjustment
Brake control levers - greasing
Brake pads - check condition and wear
Brake fluid level - check
Flexible brake tubes - replacement
Transmission elements - lubrication
Safety locks - check
Suspensions - check
Electrical system and battery - check
Headlight - adjustment
Secondary air filter - cleaning
Centre stand - lubrication
Tyre pressure and wear - check
Vehicle and brake test - road test

(*) See instructions in «Idle speed adjustment» section

AFTER 72,000 KM

300'

Engine oil - replacement
Hub oil - change
Spark plug - replacement
Air filter - clean
Engine oil - change
Oil filter (net filter) - clean
Valve clearance - adjustment
Idle speed (*) - adjustment
Throttle lever - adjustment
Pads and variator rollers - replacement
Driving belt - replacement
Odometer gear - greasing
Steering - adjustment
Cylinder ventilation system - check
Brake control levers - greasing
Brake pads - check condition and wear
Brake fluid level - check
Flexible brake tubes - replacement
Transmission elements - lubrication
Safety locks - check
Suspensions - check
Electrical system and battery - check
Headlight - adjustment
Secondary air filter - cleaning
Centre stand - lubrication
Tyre pressure and wear - check
Vehicle and brake test - road test

(*) See instructions in «Idle speed adjustment» section

Action

MAIN - 32

LX 125 - 150 4tempi Maintenance

Checking the spark advance

- To check ignition advance, use the stroboscopic light with induction pincers connected to the spark
plug power wire.

- Connect the induction pincers being careful to respect the proper polarity (the arrow stamped on the
pincers must be pointing at the spark plug).

- Place the light selector in central position (1 spark = 1 crankshaft turn as in 2-T engines).

- Start the engine and check that the light works properly and the rpm indicator can read also the high
rpm (e.g. 8000 rpm).

- If flash unsteadiness or revolution reading error is detected (e.g. half values), increase the resistive
load on the spark plug power line (10 ÷ 15 KΩ in series to HV wire).

- Operating on the flash bulb phase difference cal­ibrator, make the reference on the flywheel cover
coincide with the fan reference as shown in the
photograph. Read the advance degrees indicated
by the stroboscopic light and compare them with
those specified.

Characteristic

Ignition advance 150 check

10° ± 1° at 2000 rpm - 26° ± 1° at 6000 rpm

Ignition advance 125 check

15° ± 1° at 2000 rpm - 28° ± 1° at 6000 rpm

Spark advance variation

ADVANCE VARIATION

Specification

Operation threshold First threshold : 9000±50

Reactivation threshold First threshold : 8900±50

Spark elimination First threshold : 1 spark on 7

Desc./Quantity

Second threshold : 9300±50
Second threshold : 9200±50

Second threshold : 2 sparks on 3

MAIN - 33

Maintenance LX 125 - 150 4tempi

MAIN - 34

LX 125 - 150 4tempi Maintenance

Braking system

Level check

Proceed as follows:

- Rest the vehicle on its centre stand with the han­dlebars perfectly horizontal;

- Check the level of liquid with the related warning
light «A».
A certain lowering of the level is caused by wear
on the pads.

Top-up

Proceed as follows:

- Remove the tank cap by loosening the two
screws, remove the gasket and top up using only
the liquid specified without exceeding the maxi­mum level.

CAUTION
ONLY USE DOT 4-CLASSIFIED BRAKE FLUID.
CAUTION

AVOID CONTACT OF THE BRAKE FLUID WITH YOUR
EYES, SKIN, AND CLOTHING. IN CASE OF ACCIDENTAL
CONTACT, WASH WITH WATER.

CAUTION
BRAKING CIRCUIT FLUID IS HIGHLY CORROSIVE; MAKE

SURE THAT IT DOES NOT COME INTO CONTACT WITH
THE PAINTWORK.

CAUTION
THE BRAKE FLUID IS HYGROSCOPIC, IN OTHER WORDS,

IT ABSORBS MOISTURE FROM THE SURROUNDING AIR.
IF THE CONTENT OF MOISTURE IN THE BRAKING FLUID
EXCEEDS A CERTAIN VALUE, BRAKING WILL BE INEF­FICIENT.
NEVER USE BRAKE LIQUID IN OPEN OR PARTIALLY
USED CONTAINERS.
UNDER NORMAL CLIMATIC CONDITIONS, THE FLUID
MUST BE CHANGED EVERY 20,000 KM OR ANYWAY EV­ERY TWO YEARS.

N.B.
SEE THE BRAKING SYSTEM CHAPTER WITH REGARD TO

THE CHANGING OF BRAKE FLUID AND THE BLEEDING
OF AIR FROM THE CIRCUITS.

Recommended products

AGIP BRAKE 4 Brake fluid

MAIN - 35

Maintenance LX 125 - 150 4tempi

FMVSS DOT 4 Synthetic fluid

Headlight adjustment

Proceed as follows:

1. Place the vehicle in running order and with the
tyres inflated to the prescribed pressure, on a flat
surface 10 m away from a white screen situated in
a shaded area, making sure that the longitudinal
axis of the scooter is perpendicular to the screen;

2. Turn on the headlight and check that the bor­derline of the projected light beam on the screen
is not lower than 9/10 of the distance from the
ground to the centre of vehicle headlamp and high­er than 7/10;

3. If otherwise, adjust the right headlight with screw
«A».

N.B.
THE ABOVE PROCEDURE COMPLIES WITH THE EURO-

PEAN STANDARDS REGARDING MAXIMUM AND MINI­MUM HEIGHT OF LIGHT BEAMS. REFER TO THE STATU­TORY REGULATIONS IN FORCE IN EVERY COUNTRY
WHERE THE vehicle IS USED.

CO check

Proceed as follows:

- Remove the right side panel

- Remove the spoiler end

- Remove the magneto cover.

- Remove the band and secondary air valve as
shown in the photo.

- Connect the exhaust pipe with the rubber sleeve
of the secondary air system. This connection must
ensure that the system is airtight to avoid incorrect
readings of the CO value.

N.B.
IN CASE OF 1000 PPM UNBURNED HYDROCARBONS

(HC) >, CHECK THE IGNITION SYSTEM, THE TIMING SYS­TEM, THE VALVE CLEARANCE AND THE EXHAUST
VALVE TIGHTNESS.

N.B.
IN CASE OF UNSTABLE CO, CHECK THAT THE CARBU-

RETTOR IS CLEAN AND THAT THE FUEL SUPPLY SYS-

MAIN - 36

LX 125 - 150 4tempi Maintenance

TEM AND THE DEPRESSION SEALS WORK ADEQUATE­LY

N.B.
OTHERWISE, CHECK THE FUEL LEVEL ADJUSTMENT IN

THE TANK AND THE FUEL CIRCUIT.
N.B.
ALSO CHECK THE CARBURETION ADJUSTMENT IS OB-

TAINED WITH THE FLOW SCREW OPEN BETWEEN 2 AND
4 TURNS.

N.B.
CHECK THAT THE RESULT IS OBTAINED WITH THE

VALVE GAS IN CLOSED POSITION.

Specific tooling

020332Y Digital rev counter
494929Y Exhaust fumes analyser

Characteristic

CO Check

3.8±0.7 to 1650±50 RPM

SAS filters inspection and cleaning

Proceed as follows:

- Remove the right-hand side fairing

- Remove the screw on the rear part, to the right
of the footrest, indicated in the photograph

- Remove the spoiler terminal

- Remove the screw fixing the SAS valve to the
flywheel cover, indicated in the photograph.

MAIN - 37

Maintenance LX 125 - 150 4tempi

- Remove the 6 flywheel cover screws indicated in
the photograph and remove the flywheel cover.

- Remove the filter indicated in the photograph

- Check that the gasket is in good conditions

- Check the SAS filter housing for dents or defor­mations

- Clean the SAS filter carefully. Replace the filter if
it is damaged or deformed.
To refit, carry out the removal operations but in re­verse order.

CAUTION
WHEN TRAVELLING ON DUSTY ROADS, THE AIR FILTER

MUST BE CLEANED MORE OFTEN THAN SHOWN IN THE
SCHEDULED MAINTENANCE CHART.

CAUTION
NEVER RUN THE ENGINE WITHOUT THE SECONDARY

AIR FILTER

MAIN - 38

INDEX OF TOPICS

TROUBLESHOOTING TROUBL

Troubleshooting LX 125 - 150 4tempi

Engine

Poor performance

POOR PERFORMANCE

Possible Cause Operation

Air filter blocked or dirty. Dismantle the sponge, wash with water and shampoo, then

Fuel nozzles or cock clogged or dirty Dismantle, wash with solvent and dry with compressed air
Dirty or faulty vacuum-operated cock Check the filter on the cock, remove the petrol and wash the

Failing automatic starter on the carburettor Check the electrical wiring and mechanical movement, replace

Excessive driving belt wear Check it and replace, if necessary

Lack of compression: parts, cylinder and valves worn Replace the worn parts

Oil level exceeds maximum Check for causes and fill to reach the correct level

Excess of encrustations in the combustion chamber Descale the cylinder, the piston, the head and the valves

Incorrect timing or worn timing system elements Time the system again or replace the worn parts

Muffler obstructed Replace

Inefficient automatic transmission Check the rollers and the pulley movement, replace the dam-

Wrong valve adjustment Adjust the valve clearance properly

Overheated valves Remove the head and the valves, grind or replace the valves

Valve seat distorted Replace the head assembly

Worn cylinder, Worn or broken piston rings Replace the piston cylinder assembly or just the piston rings

soak it in a mixture of 50% petrol and 50% of specific oil (Se­lenia Air Filter Oil), then hand dry without squeezing, allow to

drip dry and then reassemble.

tank, if necessary. Replace the cock as a last resource.

if necessary.

aged parts and lubricate the driven pulley moveable guide with

Montblanc Molybdenum Grease

Rear wheel spins at idle

REAR WHEEL ROTATES WITH ENGINE AT IDLE

Possible Cause

Idling rpms too high Adjust the engine idle speed and the CO%, if necessary.

Clutch fault Check the springs / clutch masses

Starting difficulties

DIFFICULTY STARTING UP

Possible Cause

Battery flat Check the state of the battery. If it shows signs of sulphation

Faulty spark plug or incorrect ignition advance Replace the spark plug or check the ignition circuit components

- Engine flooded. Try starting-up with the throttle fully open. If the engine fails to

Incorrect valve sealing or valve adjustment Inspect the head and/or restore the correct clearance

Rpm too low at start-up or engine and start-up system dam-

aged

Altered fuel characteristics Drain off the fuel no longer up to standard; then, refill

Vacuum operated cock failure Check that fuel is adequately supplied through the pipe by ap-

Operation

Operation

replace it and bring the new battery into service charging it for

eight hours at a current of 1/10 of the capacity of the battery

itself

start, remove the spark plug, dry it and before refitting, make

the motor turn so as to expel the fuel excess taking care to

connect the cap to the spark plug, and this in turn to the ground.

If the fuel tank is empty, refuel and start up.

Check the starter motor and the kick-starter unit

plying a vacuum to the suction pipe

TROUBL - 40

LX 125 - 150 4tempi Troubleshooting

Possible Cause Operation

Failing automatic starter on the carburettor Check the electrical wiring and mechanical movement, replace

Start-up enabling buttons failure Check continuity using an Ohm meter, with the switch pressed;

Carburettor nozzles clogged or dirty Dismantle, wash with solvent and dry with compressed air

Air filter obstructed or dirty. Dismantle the sponge, wash with water and shampoo, then

soak it in a mixture of 50% petrol and 50% of specific oil (Se-

lenia Air Filter Oil), then hand dry without squeezing, allow to

Excessive oil consumption/Exhaust smoke

EXCESSIVE OIL CONSUMPTION/SMOKEY EXHAUST

Possible Cause Operation

Worn valve guides Check and replace the head unit if required

Worn valve oil guard Replace the valve oil guard

Oil leaks from the couplings or from the gaskets Check and replace the gaskets or restore the coupling seal

Worn or broken piston rings or piston rings that have not been

fitted properly

Replace the piston cylinder unit or just the piston rings

drip dry and then reassemble.

if necessary.

replace if necessary

Insufficient lubrication pressure

POOR LUBRICATION PRESSURE

Possible Cause

By-Pass remains open Check the By-Pass and replace if required. Carefully clean the

Oil pump with excessive clearance Perform the dimensional checks on the oil pump components

Oil filter too dirty Replace the cartridge filter
Oil level too low Restore the level using the recommended oil type (Selenia HI

Engine tends to cut-off at full throttle

THE MOTOR TENDS TO STOP AT MAXIMUM THROTTLE

Possible Cause

Maximum jet clogged Remove the carburettor, wash with solvent and dry with com-

Water or condensate in the carburettor tank Remove the tank, wash with solvent and dry with compressed

Level in tank too low Restore the level in the tank by bending on the float the thrust-

Engine tends to cut-off at idle

Operation

By-Pass area.

Scooter 4 Tech)

Operation

pressed air

air

ing reed of the petrol inlet rod so as to have the float parallel to

the tank level with the carburettor inverted.

THE ENGINE TENDS TO STOP AT IDLE SPEED

Possible Cause

Incorrect idle adjustment Adjust using the rpm indicator

Incorrect timing Time the system and check the timing system components

The starter remains on Check: electric wiring, circuit not interrupted, mechanical

movement and power supply; replace if necessary

Faulty spark plug or incorrect ignition advance Replace the spark plug or check the ignition circuit components

Pressure too low at the end of compression Check the thermal group seals and replace worn components

Minimum nozzle dirty Wash the nozzle with solvent and dry with compressed air

Operation

TROUBL - 41

Troubleshooting LX 125 - 150 4tempi

High fuel consumption

EXCESSIVE FUEL CONSUMPTION

Possible Cause Operation

Air filter blocked or dirty. Clean according to the procedure

Starter inefficient Check: electric wiring, circuit continuity, mechanical sliding and

Loose nozzles Check the maximum and minimum nozzles are adequately

Incorrect float level Restore the level in the tank by bending on the float the thrust-

ing reed of the petrol inlet rod so as to have the float parallel to

the tank level with the carburettor inverted.

power supply

fixed in their fittings

Transmission and brakes

Clutch grabbing or performing inadequately

IRREGULAR CLUTCH PERFORMANCE OR SLIPPAGE

Possible Cause Operation

Slippage or irregular functioning Check that there is no grease on the masses.

Check that the faying surface between the clutch masses and
the clutch bell is mainly in the middle and with equivalent spec-

ifications on the three masses.

Check that the clutch bell is not scored or worn abnormally

Never run the engine without the clutch bell

Insufficient braking

INEFFICIENT OR NOISY BRAKING

Possible Cause

Worn brake pads or shoes Replace the brake pads or shoes and check for brake disk or

Front brake disk loose or deformed Check the brake disc screws are locked; use a dial gauge and

a wheel mounted on the vehicle to measure the axial shift of

Air bubbles inside the hydraulic braking system Carefully bleed the hydraulic braking system, (there must be

no flexible movement of the brake lever).

Fluid leakage in hydraulic braking system Failing elastic fittings, plunger or brake pump seals, replace

Excessive backlash in the rear brake control cable Adjust the backlash with the appropriate adjuster located on

the back part of the crankcase.

Operation

drum wear conditions.

the disc.

Brakes overheating

BRAKES OVERHEATING

Possible Cause

Rubber gaskets swollen or stuck Replace gaskets.

Compensation holes on the pump clogged Clean carefully and blast with compressed air

Brake disc slack or distorted Check the brake disc screws are locked; use a dial gauge and

a wheel mounted on the vehicle to measure the axial shift of

Defective piston sliding Check calliper and replace any damaged part.

Operation

the disc.

TROUBL - 42

LX 125 - 150 4tempi Troubleshooting

Electrical system

Battery

BATTERY

Possible Cause Operation

Battery The battery is the electrical device in the system that requires

Turn signal lights malfunction

the most frequent inspections and thorough maintenance. If the
vehicle is not used for some time (1 month or more) the battery

needs to be recharged periodically. The battery runs down
completely in the course of 5 ÷ 6 months. If the battery is fitted
on a motorcycle, be careful not to invert the connections, keep-

ing in mind that the black ground wire is connected to the
negative terminal while the red wire is connected to the terminal
marked+. Follow the instructions in the ELECTRICAL SYSTEM

chapter for the recharging of the batteries.

TURN INDICATOR NOT WORKING

Possible Cause Operation

Electronic ignition device failure With the key switch set to "ON" jump the contacts 1 (Blue-

Steering and suspensions

Heavy steering

Possible Cause

Steering hardening Check the tightening of the top and bottom ring nuts. If irregu-

Excessive steering play

Black) and 5 (Orange) on the control unit connector.

If by operating the turn indicator control the lights are not stead-

ily on, replace the control unit; otherwise, check the cable

harness and the switch.

STEERING HARDENING

Operation

larities in turning the steering continue even after making the
above adjustments, check the seats on which the ball bearings
rotate: replace them if they are recessed or if the balls are flat-

tened.

EXCESSIVE STEERING CLEARANCE

Possible Cause

Excessive steering backlash Check the tightening of the top ring nut. If irregularities continue

in turning the steering even after making the above adjust-

ments, check the seats in which the ball bearings rotate: re-

Operation

place if they are recessed.

TROUBL - 43

Troubleshooting LX 125 - 150 4tempi

Noisy suspension

NOISY SUSPENSION

Possible Cause Operation

Noisy suspension If the front suspension is noisy, check: that the front shock ab-

sorber works properly and the ball bearings are good condition.

Finally, check the locking torque of the wheel axle nut, the

brake calliper and the disc. Check that the swinging arm con-

necting the engine to the chassis and the rear shock absorber

work properly.

Suspension oil leakage

OIL LEAKAGE FROM SUSPENSION

Possible Cause Operation

Oil leakage from suspension Replace the damper.

TROUBL - 44

INDEX OF TOPICS

ELECTRICAL SYSTEM ELE SYS

Electrical system LX 125 - 150 4tempi

Legend

1. Rear brake stop button

2. High/low beam selector

3. Turn indicator selector

4. Horn button

5. Immobilizer aerial

6. Electronic ignition

7. Relay

8. Horn

9. Turn indicator bulb

10. Front left indicator.

11. Voltage regulator

12. HV coil

ELE SYS - 46

LX 125 - 150 4tempi Electrical system

13. Heater

14. Automatic choke

15. Pick-up

16. Magneto

17. Starter motor

18. Fuse holder with 2 15A fuses

19. 2 turn indicator bulbs

20. Rear left indicator

21. Rear parking and brake light bulb

22. Complete taillight

23. License plate light bulb

24. License plate light cover

25. 2 turn indicator bulbs

26. Rear right indicator with bulb

27. Fuel warning light transmitter

28. Starter motor contactor

29. Battery 12V-9°

30. Engine oil pressure sensor

31. Immobilizer diagnostic instrument output

32. Front right indicator

33. Turn indicator bulb

34. Key switch

35. Start button

36. Front brake stop button

37. Fuse holder with 2 7.5 A fuses

38. Anti-theft and diagnostics LED

39. Complete headlight

40. Rear parking light bulb

41. Bulb for high/dipped beam light 12V - 355W / 60W

42. High beam indicator lamp

43. Engine oil pressure lamp

44. Right indicator lamp

45. Fuel warning lamp

46. Left indicator lamp

47. Instrument lighting light bulb

48. Lights indicator lamp

49. Odometer with lamps and level indicator instrument

50. Space for acoustic lamp

ELE SYS - 47

Electrical system LX 125 - 150 4tempi

Wire colour coding
R = Red
B = White
Bl = Blue
N = Black
V= Green
Rs = Pink
Mr = Brown
Gr = Grey
Az = Light blue
G = Yellow
Vi = Purple
A = Orange

Conceptual diagrams

Ignition

Specification

1 electronic control unit
2 Magneto flywheel
3 Pick - up
4 HV coil
5 Spark plug
6 Voltage regulator

ELE SYS - 48

IGNITION

Desc./Quantity

LX 125 - 150 4tempi Electrical system

Headlights and automatic starter section

LIGHTS AND AUTOMATIC CHOKE

Specification

1 electronic control unit
2 Carburettor heater
3 Automatic starter
4 Key switch
5 no. 2 main fuses 15A
6 Battery 12V-9Ah
7 Headlamp relay
8 Light switch
9 Low-beam light bulb 12V - 55W
10 High-beam light bulb 12V-55W
11 High beam indicator lamp 12V - 1.2W
12 Fuse
13 Position light bulb 12V - 5W
14 Lights indicator lamp 12V - 1.2W
15 No 2 bulbs for instrument panel lighting 12V - 1.2W
16 No 1 bulb for instrument panel lighting 12V - 2W
17 Taillight bulb 12V - 5W
18 License plate bulb 12V - 5W

Desc./Quantity

ELE SYS - 49

Electrical system LX 125 - 150 4tempi

Battery recharge and starting

BATTERY CHARGER AND STARTING

Specification

1 Magneto flywheel
2 Voltage regulator
3 Pick - up
4 Main fusible 15A
5 Battery 12V-9Ah
6 Starter relay
7 Starter motor
8 Start up button
9 Front and rear brake light button
10 Brake light filament 12V-21W
11 Fuse 7.5 A
12 Key switch
13 electronic control unit

Desc./Quantity

ELE SYS - 50

LX 125 - 150 4tempi Electrical system

Level indicators and enable signals section

CONSENSES AND LEVEL INDICATORS

Specification

1 electronic control unit
2 Battery 12V-9Ah
3 Main fusible 15A
4 Key switch
5 Engine oil pressure sensor
6 Engine oil pressure warning light 12V - 2W
7 Reserve fuel light 12V-1,2W
8 Fuel gauge
9 Fuel level sender
10 Fuse 7.5 A
11 Immobilizer aerial
12 Low engine oil pressure sensor
13 Immobiliser LED
14 Front and rear brake light button
15 Filament for rear brake light 12V - 21W

Desc./Quantity

ELE SYS - 51

Electrical system LX 125 - 150 4tempi

Turn signal lights

TURN INDICATORS AND HORN

Specification

1 electronic control unit
2 Indicators switch
3 4 Turn indicator bulbs 12V-10W
4 Turn signal warning light bulbs 12V - 2W
5 Main fusible 15A
6 Battery 12V-9Ah
7 Horn
8 Fuse 7.5 A
9 Key switch
10 Horn button
11 Space for turn indicator acoustic lamp

Desc./Quantity

Instruments and warning lights control board

ELE SYS - 52

LX 125 - 150 4tempi Electrical system

4-PIN CONNECTOR

Specification Desc./Quantity

1 Ground lead
2 Left turn indicator warning light
3 Right turn indicator warning light
4 Not used

5-PIN CONNECTOR

Specification Desc./Quantity

1 Fuel gauge
2 High-beam lamp warning light 12V - 1.2W
3 Engine oil pressure warning light 12V - 2W
4 + permanent power supply
5 Low fuel warning light
6 Instrument panel lighting and headlamp warning light

2-PIN CONNECTOR

Specification Desc./Quantity

1 Immobiliser/diagnosis LED
2 Immobiliser/diagnosis LED

Checks and inspections

Immobiliser

The electric ignition system is fed with direct cur­rent and is protected by an anti-theft immobilizer
integrated to the control unit.
The ignition system consists of:

- electronic control unit

- immobilizer aerial

- master and service keys with built-in transponder

- HV coil

- diagnosis LED
The diagnosis LED also works as a blinking light
to deter theft. This function is activated every time
the key switch is turned to «OFF», and it remains
active 48 hours so as not to affect the battery
charge.
When the ignition switch is set to «ON», the theft
deterring blinker function is deactivated. Subse­quently, a flash confirms the switching to «ON».
The duration of the flash depends on the electronic
control unit program (see figure).

ELE SYS - 53

Electrical system LX 125 - 150 4tempi

Whenever the LED is off and remains so, even
when switching it to «ON», it is necessary to check
if:

- the battery is charged

- 15A main fuse is working correctly.
Connect the immobilizer tester to the diagnosis
socket (see ET4 125 manual) located behind the
front left fuse box flap.
If the serial LED remains off, check the electronic
control unit supply as follows:

Detach the connector from the ECU and check the
following:

- Presence of battery potential difference between
terminal 4 (Red/Blue) and earth

- Presence of battery potential difference between
terminals 4 (Red/Blue) and 8 (black), as shown in
the figure.

- Presence of battery potential difference between
terminals 5 and 8 with the key-switch onto «ON».
If no anomalies are found, replace the electronic
control unit.

Virgin circuit

If the ignition system has not been programmed,
the engine can be started but it will run limited to
2000 rpm. When trying to accelerate, some evi­dent loss of power may be felt.
Program the system with the MASTER (Brown)
and SERVICE (Blue) keys as follows:

- Insert the MASTER key, turn it to "ON" and keep
it in that position for 2 seconds (limit values: 1 ÷ 3
seconds).

ELE SYS - 54

LX 125 - 150 4tempi Electrical system

- Alternatively insert all the available black keys
and turn each one of them to "ON" for 2 seconds.

- Insert the MASTER key again and turn it to "ON"
for 2 seconds.
The maximum time to change keys is 10 seconds.
A maximum of 7 service keys (blue) can be pro­grammed at one time.
Sequence and times must be strictly observed or
it will be necessary to repeat the procedure from
the start.
Once the control unit has been programmed, the
control unit is inseparably matched with the MAS­TER key transponder.
This matching allows programming further service
keys in case of loss, replacement, etc. Each new
time new data is programmed the previously stor­ed one is deleted.
If a service key setting is lost, it is essential to
carefully check the efficiency of the high voltage
system:
Shielded cap resistance ~ 5000 Ω.
In any case, it is advisable to use resistive spark
plugs as shown in the figure.

Diagnostic codes

The flash indicating the switching to "ON" (0.7-sec
flash) can be followed by a phase of programmed
failure warnings.
That is, the LED is off for 2 seconds, and then di­agnosis codes are transmitted with 0.5-sec flash­es.
After the failure code indication, a steadily on LED
signals that ignition is disabled; see the table:

2-FLASH CODE

Example with programmed electronic control unit,
no transponder and/or aerial malfunction

Ignition disabled-Vehicle immobilised

ELE SYS - 55

Electrical system LX 125 - 150 4tempi

3-FLASH CODE

Example with programmed electronic control unit,
aerial working properly and unknown transponder
code.

Ignition disabled-Vehicle immobilised

Diagnostic code - 2 flashes

When the 2-flash code is detected, carry out the following checks:

- Check if the failure continues even after changing key (including the MASTER key). If the failure
persists with any key, disconnect the aerial connector from the electronic control unit and check the
aerial continuity with the multimeter.
If it does not work, replace the aerial.
If no faults are found, replace the control unit.

CAUTION

BEFORE PROGRAMMING THE NEW ELECTRONIC CONTROL UNIT CHECK THAT NO FAILURE
CODE IS INDICATED. THIS IS TO AVOID SPOILING A NEW CONTROL UNIT UNNECESSARILY.

Specific tooling

020331Y Digital multimeter

Electric characteristic

Resistance value

~ 7 ÷ 9 Ohm

Diagnostic code - 3 flashes

If the 3-flash code is detected, check if the failure occurs when the MASTER key in inserted into the
key switch.

- If the failure disappears when the MASTER key is used, proceed with coding a new service key (Blue).

- If the failure persists, it means that the MASTER key and the control unit are not linked; in this case,
replace the control unit and then encode the keys.
The immobilizer system is efficient when, after switching over to «ON», only a 0.7-sec flash is detected
(see diagram).
In this case, the engine can be started.

ELE SYS - 56

LX 125 - 150 4tempi Electrical system

Example with programmed control unit, trans­ponder, programmed key and working aerial. The

ignition is enabled (regular use conditions)

Ignition circuit

All the control operations of the system that entail disconnecting cables (to check connections and the
devices making up the ignition circuit) must be done with the engine off: if this is not done, the controls
might be irretrievably damaged.
The battery provides the basic power supply. The system is adjusted so that the start-up system im­mediately detects an eventual battery voltage drop, and this is practically irrelevant for the ignition
system.
The Pick-Up is connected to the control unit by a single cable; therefore, the control unit is connected
to the Pick-Up by the chassis and the engine ground lead.
To avoid disturbances in the ignition system during start-up, it is very important that the engine-chassis
ground connection bonding is efficient.

No spark plug

When noticing no spark plug proceded as follows:

- Pick-Up inspection.

Detach the ECU connector and check for continu­ity between terminals 2 (Green) and 8 (Black).
The inspection must include the pick-up and it's
power cable.
If an open circuit is found, repeat the inspection
between the flywheel connector and earth. If un­acceptable values are found, proceed by replacing
the pick-up, otherwise repair the cable.

Electric characteristic

Pick-up resistance value

Pick-up resistance value: 105 ÷ 124 Ohm

ELE SYS - 57

Electrical system LX 125 - 150 4tempi

- H.T. coil primary circuit inspection

Detach the connector from the ECU and check for
continuity between terminals 3 (purple) and 8
(black) (see figure).
If unacceptable values are found, repeat the in­spection directly from the positive and negative
terminals of the H.T. coil primary circuit.
If the values are within the prescribed limit, pro­ceed by repairing the wiring or reattaching all wir­ings, otherwise replace the H.T. coil.

Electric characteristic

High voltage coil primary resistance value

High voltage coil primary resistance value: 0.4 ÷

0.5 Ohm

- HV coil secondary check

Disconnect the spark plug cap from the HV cable and measure the resistance between the HV cable
terminal and the HV coil negative terminal (see figure).
If non-conforming values are measured, replace the HV coil. To carry out a more complete diagnosis,
check the peak voltage with the multimeter adaptor.

Specific tooling

020409Y Multimeter adaptor - Peak voltage detection

Electric characteristic

High voltage coil secondary resistance value

High voltage coil secondary resistance value: ~ 3000 ± 300 Ohm

- Pick-Up

Detach the ECU connector and connect the posi­tive terminal to connector no. 2 and the negative
terminal to connector no. 8 (see figure).
Crank the engine using the starter motor and
check the tension produced by the pick-up.

ELE SYS - 58

LX 125 - 150 4tempi Electrical system

If unacceptable values are found, replace the Pick­Up.

N.B.
THE MULTIMETER MUST BE SELECTED TO DETECT

CONTINUOUS VOLTAGE.

Electric characteristic

Pick-Up voltage value

Pick-Up voltage value: > 2 Volt

- H.V. coil

With the control unit and HV coil connected to the
circuit, measure the voltage of the coil primary dur­ing the start-up test with the voltage peak adaptor
and connect the positive terminal to the earth one
and the negative to the coil positive connector.
If non-conforming values are measured, replace
the control unit.

THE POSITIVE TERMINAL OF THE HV COIL PRIMARY IS
BLACK.

Electric characteristic

High voltage coil voltage value

High voltage coil voltage value: > 100 Volt

Battery recharge circuit

The recharge system is provided with a three phase alternator with permanent flywheel.
The alternator is directly connected to the voltage regulator.
In turn, the latter is directly connected to earth and to the battery positive passing through the 15A safety
fuse.
This system therefore requires no connection to the key switch.
The three- phase generator provides good recharge power and at low revs a good compromise is
achieved between generated power and idle stability.
For this reason, it is very important that the idle speed is adjusted as prescribed.

Specific tooling

020333Y Single battery charger
020334Y Multiple battery charger

ELE SYS - 59

Electrical system LX 125 - 150 4tempi

Stator check

Disconnect the connector from the voltage regu­lator and check there is continuity between any
yellow cable and the other two cables.

Electric characteristic

Ohm value:

0.7 ÷ 0.9 Ohm

Also check that all yellow cables are insulated from
the ground connection.
If non-conforming values are detected, repeat the
checks directly to the stator. In case of further rep­etitions of incorrect values replace the stator or
repair the wiring.

Voltage regulator check

With a perfectly charged battery and lights off,
measure voltage at the battery poles with a high
running engine.
The voltage should not exceed 15.2 Volt.
In case higher voltages are detected, replace the
regulator.
In case of voltage values lower than 14 Volt, check
the stator and the corresponding cable harness.

ELE SYS - 60

LX 125 - 150 4tempi Electrical system

Recharge system voltage check

Connect an ammeter induction clamp to the volt­age regulator positive terminal, measure the bat­tery voltage and turning on the vehicles lights with
engine off, wait for the voltage to set at about 12
V. Start the engine and measure the current gen­erated by the system with lights on and a high
running engine.
In case the generated current value is lower than
8A, repeat the test using a new regulator and/sta­tor alternatively.

Choke Inspection

Refer to the engine section to check the resistance
and operating conditions of the component. As re­gards voltage supply, keep the connector connec­ted to the system and check that the two terminals
receive battery voltage when the engine is on
(see figure).
If no voltage is detected, connect the multimeter
negative terminal to the ground lead and the pos­itive terminal to the automatic starter orange cable;
with the key switch set to "ON" check whether
there is battery voltage; if there is no voltage,
check the wiring connections to the key switch.

If battery potential is found, repeat the inspection
from the connector to the ECU.
After detaching the choke device, start the engine
and, while at idle, check for tension connecting the
positive terminal of the multimetre to terminal 5
(Orange) and the negative to terminal 7 (White/
Black) (see figure).

ELE SYS - 61

Electrical system LX 125 - 150 4tempi

If no tension is found, replace the ECU; otherwise
check the wiring between the choke device and the
ECU.

Turn signals system check

- If the turn signal lights are faulty, proceed as fol­lows:

- Detach the ECU connector and check for battery
tension between terminal 5 (Orange) and earth,
with the key-switch onto «ON».

- Check the same is present between terminals 5
(Orange) and 8 (Black).

If no tension is measured, check the wiring, other­wise proceed as follows:

- Jumper terminals 1 (Black/Blue) and 5 (Orange),
see figure, and alternately operate the turn signal
switch towards left and right wit the key-switch on­to «ON» and check the bulbs go off.
If this happens, replace the ECU, as faulty.
If this does not happen, check the wiring between
the ECU and the turn signal switch, hence repeat
the test.

Sealed battery

If the vehicle is provided with a sealed battery, the only maintenance required is the check of its charge
and recharging, if necessary.
These operations should be carried out before delivering the vehicle, and on a six-month basis while
the vehicle is stored in open circuit.
Besides, upon pre-delivery it is therefore necessary to check the battery charge and recharge it, if
required, before storing the vehicle and, afterwards, every six months.

INSTRUCTIONS FOR THE RENEWAL RECHARGE AFTER OPEN-CIRCUIT STORAGE

1) Voltage check up

Before installing the battery on the vehicle, check the open circuit voltage with a regular tester.

- If voltage exceeds 12.60 V, the battery can be installed without any renewal recharge.

- If voltage is below 12.60 V, a renewal recharge is required as explained in 2).

ELE SYS - 62

LX 125 - 150 4tempi Electrical system

2) Constant voltage battery charge mode

- Constant voltage charge equal to 14.40 ÷ 14.70V

-Initial charge voltage equal to 0.3 ÷ 0.5 for Nominal capacity

- Charge time:
10 to 12 h recommended
Minimum 6 h
Maximum 24 h

3) Constant current battery charge mode

- Charge current equal to 1/10 of the battery rated capacity

- Charge time: Maximum 5 h

Dry-charge battery

WARNING

- Battery electrolyte is toxic and it may cause serious burns. It contains sulphuric acid. Avoid contact
with eyes, skin and clothing. In case of contact with eyes or skin, flush abundantly with water for about
15 minutes and seek immediate medical attention.
In the event of accidental ingestion of the fluid, immediately drink large quantities of water or milk. Follow
with milk of magnesia, beaten egg or vegetable oil. Seek immediate medical attention
Batteries produce explosive gases; keep clear of free flames, sparks or cigarettes; ventilate the area
when recharging the battery indoors.
Always protect your eyes when working close to batteries.

Keep out of the reach of children.

Commissioning dry-charged batteries :

1) - Remove the short closed tube and the caps,
then pour sulphuric acid into the cells using the
type specified for batteries with a specific gravity
of 1.26, corresponding to 30 Be at a minimum tem­perature of 15°C until the upper level is reached.

2) - Leave to rest for at least 2 hours; then, restore
the level with sulphuric acid.

3) - Within the following 24 hours, recharge using
the specific battery charger (single) or (multiple) at
a density of about 1/10 of the battery nominal ca­pacity until fully charged; check that the acid den­sity is about 27, corresponding to 31 Be, and that
these values are stabilised.

4) - Once the charge is over, level the acid (by
adding distilled water). Close and clean carefully.

ELE SYS - 63

Electrical system LX 125 - 150 4tempi

5) Once the above operations have been per­formed, install the battery on the vehicle ensuring
that it is wired up properly.

1 Hold the vertical tube
2 Look at the level
3 The float must be freed

WARNING

- ONCE THE BATTERY HAS BEEN INSTALLED IN THE VE­HICLE IT IS NECESSARY TO REPLACE THE SHORT TUBE
(WITH CLOSED END) NEAR THE + POSITIVE TERMINAL
WITH THE CORRESPONDING LONG TUBE (WITH OPEN
END), THAT YOU FIND FITTED TO THE VEHICLE, TO EN­SURE THAT THE GASES THAT FORM CAN ESCAPE
PROPERLY.

Specific tooling

020333Y Single battery charger
020334Y Multiple battery charger

Battery maintenance

The battery is an electrical device which requires careful monitoring and careful maintenance. The
maintenance rules are:

1) Electrolyte level check

The electrolyte level must be checked frequently and must reach the upper level. Only use distilled
water, to restore this level. If it is necessary to add water too frequently, check the vehicle electrical
system: the battery works overcharged and is subject to quick wear.

2)Load status check

After restoring the electrolyte level, check its density using an appropriate densitometer (see the figure).
When the battery is charged, you should detect a density of 30 to 32 Bé corresponding to a specific
weight of 1.26 to 1.28 at a temperature of no lower than 15° C.
A density reading of less than 20° Bé indicates that the battery is completely flat and it must therefore
be recharged.
If the scooter is not used for a given time (1 month or more) it will be necessary to periodically recharge
the battery.
The battery runs down completely in the course of three months. If it is necessary to refit the battery in
the vehicle, be careful not to reverse the connections, remembering that the ground wire (black) marked
(-) must be connected to the -negative clamp while the other two red wires marked (+) must be con­nected to the clamp marked with the +positive sign.

3) Recharging the battery

Remove the battery from the vehicle removing the negative clamp first.
Regular bench charging must be carried out with the specific battery charger, (single) or (multiple),
setting the battery charger selector to the type of battery to be recharged. Connections to the power
supply source must be implemented by connecting the corresponding poles (+ to+ and - to -).

ELE SYS - 64

LX 125 - 150 4tempi Electrical system

4) Battery cleaning

The battery should always be kept clean, especially on its top side, and the terminals should be coated
with Vaseline.

WARNING

BEFORE RECHARGING THE BATTERY, REMOVE THE PLUGS OF EACH CELL. KEEP SPARKS
AND NAKED FLAMES AWAY FROM THE BATTERY WHILE RECHARGING.

CAUTION

NEVER USE FUSES WITH A CAPACITY HIGHER THAN THE RECOMMENDED CAPACITY. USING
A FUSE OF UNSUITABLE RATING MAY SERIOUSLY DAMAGE THE VEHICLE OR EVEN CAUSE
A FIRE.

CAUTION

ORDINARY AND DRINKING WATER CONTAINS MINERAL SALTS THAT ARE HARMFUL FOR
THE BATTERY. FOR THIS REASON, YOU MUST ONLY USE DISTILLED WATER.

CAUTION

TO ENSURE MAXIMUM PERFORMANCE THE BATTERY MUST BE CHARGED BEFORE USE.
INADEQUATE CHARGING OF THE BATTERY WITH A LOW ELECTROLYTE LEVEL BEFORE IT
IS FIRST USED SHORTENS THE LIFE OF THE BATTERY.

Specific tooling

020333Y Single battery charger
020334Y Multiple battery charger

ELE SYS - 65

INDEX OF TOPICS

ENGINE FROM VEHICLE ENG VE

LX 125 - 150 4tempi Engine from vehicle

Exhaust assy. Removal

- Remove the 2 fixing nuts from the manifold to the
head

- Unscrew the 2 screws fixing the muffler to the
housing; then remove the whole muffler paying at­tention to the interference between its supporting
bracket and the cooling cover.

Removal of the engine from the vehicle

Disassembling the engine from chassis

- Remove the left and right side fairings

- Remove the helmet compartment
Remove the full muffler assembly.

- Remove the 3 rear brake transmission fixing
screws indicated in the photograph

- Disconnect the rear brake transmission unscrew­ing the set screw

ENG VE - 67

Engine from vehicle LX 125 - 150 4tempi

- Disconnect the belt cooling tube and the swinging
arm retaining spring shown in the photograph

- Disconnect the spark plug tube

- Remove the throttle control cable from the car­burettor, indicated in the photograph

- Remove the fuel supply pipe from the carburettor

- Remove the fuel valve low-pressure pipe from the
manifold as shown in the photograph

ENG VE - 68

LX 125 - 150 4tempi Engine from vehicle

- Remove the flywheel wiring connector, the earth
terminal and the starter motor positive cable indi­cated in the figure

- Remove the protection sheath indicated in the
figure and disconnect the automatic starter and
carburettor heater connections

- Unscrew the engine pin-swinging arm nut on the
right-hand side of the vehicle and slide off the pin
on the left hand side

- Support the vehicle adequately (with a jack) and
remove the shock absorber lower clamping. The
engine is now free.

ENG VE - 69

INDEX OF TOPICS

ENGINE ENG

LX 125 - 150 4tempi Engine

This section describes the operations to be carried out on the engine and the tools to be used.

Automatic transmission

Transmission cover

- To remove the transmission cover it is necessary
to remove the rear plastic cover first by inserting a
screwdriver in the corresponding slotted holes.
Using the clutch bell lock wrench, remove the driv­en pulley axle locking nut and recover the washer.

- Remove the cap/dipstick from the engine oil filling
hole.

- Remove the 10 screws and the earth cable fas­tened under one of them.

- Remove the transmission cover. If this operation
is performed directly on the vehicle, it is necessary
to remove the cooling air coupling and the three air
filter housing retainers.

Specific tooling

020423Y driven pulley lock wrench

Kickstart

- Check the following for wear: toothed section,
toothed section shaft, cover seat bushing, pinion
shaft and its seating in the crankcase and the re­turn spring.

- Remove the damaged components.

- Lubricate the spring with the recommended
grease.

- Remove the toothed sector and load the spring
with an appropriate tool.

- Refit the washer, the seeger ring and the Kick­start lever.

Specific tooling

020432Y Tool to fit the start-up sector spring

Recommended products

ENG - 71

Engine LX 125 - 150 4tempi

AGIP GREASE MU3 Grease for odometer
transmission gear case

Soap-based lithium grease with NLGI 3; ISO-L­XBCHA3, DIN K3K-20

- Operating the starter lever, load the spring and
introduce the pinion in its seat.

- Refit the intake throat with the 3 screws and the
Kick-starter cover with the 4 screws. Tighten the
screws to the prescribed torque.

- Remove the start-up pinion pushing the starter
lever.

- Unscrew the kick starter screw, remove the lever.

-Remove the seeger ring and the washer indicated
in the figure.

-Pull out the toothed section.

WARNING
THE SECTION KEEPS THE SPRING SET, BE CAREFUL SO

AS NOT TO CAUSE ANY ACCIDENTS

Air duct

- Unscrew the Torx screws fixing the air manifold
bulkhead and remove the bulkhead.

- Remove the 3 screws, then take out the manifold
as well as the filter.

ENG - 72

LX 125 - 150 4tempi Engine

Removing the driven pulley shaft bearing

- Remove the clip from the inside of the cover.

- Use the specific tools to remove the bearing from
the crankcase.

CAUTION
USE AN APPROPRIATE REST SURFACE TO AVOID DAM-

AGING THE COVER PAINT.

Specific tooling

020376Y Adaptor handle
020375Y Adaptor 28 x 30 mm

Refitting the driven pulley shaft bearing

- Heat up the crankcase inside with the hot air gun.

- Insert the bearing in its housing, refit the Seeger
ring.

N.B.
ALWAYS REPLACE THE BEARING WITH A NEW ONE

UPON REFITTING.

Specific tooling

020151Y Air heater
020376Y Adaptor handle

ENG - 73

Engine LX 125 - 150 4tempi

020357Y 32 x 35 mm adaptor
020412Y 15 mm guide

Removing the driven pulley

- Remove the spacer, the clutch bell and the whole
driven pulley unit.

N.B.
THE UNIT CAN ALSO BE REMOVED WITH THE DRIVING

PULLEY MOUNTED.

Inspecting the clutch drum

- Check that the clutch bell is not worn or damaged.

- Measure the clutch bell inside diameter.

Characteristic

Max. value clutch bell

Max. value: Ø 134.5 mm

Clutch bell standard value

Standard value: Ø 134 - 134.2 mm

Checking the bell working surface eccentricity

- Install the bell on a driven pulley shaft using 2
bearings (inner diameter 15 and 17 mm).

- Lock with the original spacer and nut.

- Place the bell/shaft assembly on the support to
check the crankshaft alignment.

ENG - 74

LX 125 - 150 4tempi Engine

- Using a feeler pin gauge and the magnetic base,
measure the bell eccentricity.

- Repeat the measurement in 3 positions (Central,
internal, external).

- If faults are found, replace the bell.

Specific tooling

020074Y Support base for checking crankshaft
alignment

020335Y Magnetic support for dial gauge

Characteristic

clutch bell inspection: Limit eccentricity.

Admissible limit eccentricity: 0.15 mm

Removing the clutch

- Prepare the locking tool for the driven pulley with
the pins half-screwed in the tool set to «C».

- Fit the driven pulley unit in the tool so as the bolt
get into the masses clutch support holes. After­wards make the support screw make contact with
a minimum force.

- Using the specific wrench, inserted 46 mm from
the side, remove the clutch central locking nut.

- Separate the driven pulley into its components (clutch with fan and contrast spring with plastic fittings).

CAUTION

THE TOOL MUST BE FIRMLY FIXED IN THE VICE AND THE CENTRAL SCREW MUST NOT BE
TIGHTENED WITH EXCESSIVE TORQUE AS THIS MAY DAMAGE THE PULLEY OR DEFORM THE
SPECIFIC TOOL.

Specific tooling

020444Y Tool for fitting/ removing the driven pulley clutch
020444Y009 46x55 Wrench

ENG - 75

Engine LX 125 - 150 4tempi

Inspecting the clutch

- Check the thickness of the clutch mass friction
material.

- The masses must not show traces of lubricants;
otherwise, check the driven pulley unit seals.

N.B.
UPON RUNNING-IN, THE MASSES MUST EXHIBIT A CEN-

TRAL CONTACT SURFACE AND MUST NOT BE DIFFER­ENT FROM ONE ANOTHER.
VARIOUS CONDITIONS CAN CAUSE THE CLUTCH TO
TEAR.

CAUTION
DO NOT OPEN THE MASSES USING TOOLS TO PREVENT

A VARIATION IN THE RETURN SPRING LOAD.

Characteristic

Check minimum thickness

1 mm

Pin retaining collar

- Remove the collar with the aid of 2 screwdrivers.

- Remove the 3 guide pins and the movable half­pulley.

Removing the driven half-pulley bearing

- Remove the retaining ring using two flat blade
screwdrivers.

- Using a hammer and pin, knock the ball bearing
out as shown in the figure.

- Remove the roller bearing using the specific ex­tractor.

N.B.
REST THE HALF-PULLEY ON A WOOD SURFACE TO

AVOID DAMAGING THE THREADED RINGLET OF THE
DRIVEN PULLEY UPON REMOVING IT.

Specific tooling

ENG - 76

LX 125 - 150 4tempi Engine

020375Y Adaptor 28 x 30 mm
020376Y Adaptor handle
020439Y 17 mm guide

Inspecting the driven fixed half-pulley

- Measure the external diameter of the pulley bush­ing.

Characteristic

Minimum diameter permitted

Ø 40.96 mm

Standard diameter

Ø 40.965 mm

Inspecting the driven sliding half-pulley

- Remove the 2 inner sealing rings and the two O­rings.

- Measure the inside diameter of the mobile half­pulley bushing.

Characteristic

Minimum admissible diameter

Ø 41.08 mm

Standard diameter

Ø 41.035 mm

ENG - 77

Engine LX 125 - 150 4tempi

Refitting the driven half-pulley bearing

- Assemble a new roller case using the specific
punch, fit the bearing with the label facing outward
and insert it completely up to the punch on the half­pulley.

N.B.
REST THE HALF-PULLEY ON A WOOD SURFACE TO

AVOID DAMAGING THE THREADED RINGLET OF THE
DRIVEN PULLEY UPON REMOVING IT.

Specific tooling

020424Y Driven pulley roller casing fitting
punch

- To assemble the new ball bearing insert it com­pletely down in its housing with the specific punch
and finally assemble the Seeger ring.

Specific tooling

020375Y Adaptor 28 x 30 mm
020376Y Adaptor handle
020439Y 17 mm guide

Refitting the driven pulley

- Check that the faying surfaces between the 2
half-pulleys and the belt do not show any signs of
wear, scoring and grease.

- Insert the new oil seals and O-rings on the mov­able half-pulley.

- Assemble the half-pulley on the ringlet with the
appropriate protection sheath.

- Make sure the pins and collar are not worn, re­assemble the pins and collar.

- Use a greaser with a curved spout to lubricate the
driven pulley unit with around 6 g of grease. This
operation must be done through one of the holes
inside the bushing until grease comes out of the
opposite hole. This operation is necessary to avoid
the presence of grease beyond the O-rings.

Specific tooling

ENG - 78

LX 125 - 150 4tempi Engine

020263Y Sheath for driven pulley fitting

Recommended products

AGIP GREASE SM 2 Grease for the tone wheel
revolving ring

Soap-based lithium grease containing NLGI 2 Mo­lybdenum disulphide; ISO-L-XBCHB2, DIN
KF2K-20

Inspecting the clutch spring

- Measure the unloaded length of the spring of the
movable driven half-pulley.

Characteristic

Standard length:

106 mm

Refitting the clutch

- Check the thickness of the clutch mass friction
material.

-The masses must not show traces of lubricants;
otherwise, check the driven pulley unit.

N.B.
UPON RUNNING-IN, THE MASSES MUST EXHIBIT A CEN-

TRAL CONTACT SURFACE AND MUST NOT BE DIFFER­ENT FROM ONE ANOTHER. VARIOUS CONDITIONS CAN
CAUSE THE CLUTCH TO TEAR.

CAUTION
DO NOT OPEN THE MASSES USING TOOLS SO AS TO

PREVENT A VARIATION IN THE RETURN SPRING LOAD.

Characteristic

Minimum thickness permitted:

1 mm

ENG - 79

Engine LX 125 - 150 4tempi

- Support the driven pulley spring compressor ap­propriate tool with the control screw in vertical axis.

- Arrange the tool with the medium length pins
screwed in position "C" on the inside.

- Introduce the adapter ring 11 with the chamfering
facing upwards.

- Insert the clutch on the adapter ring.

- Lubricate the end of the spring that abuts against
the servo-system closing collar.

- Insert the spring with its plastic holder in contact
with the clutch.

- Insert the driving belt into the pulley unit accord­ing to their direction of rotation.

- Insert the pulley unit with the belt into the tool.

- Slightly preload the spring.

- Make sure that the clutch is perfectly inserted into
the adapter ring before proceeding to tighten the
clutch nut.

- Place the tool in the clamp with the control screw
on the horizontal axis.

- Fully preload the spring.

- Apply the clutch fixing nut and tighten it to the
prescribed torque using the special 46x55 wrench.

- Loosen the tool clamp and insert the belt accord­ing to its direction of rotation.

- Lock the driven pulley again using the specific
tool.

- Preload the clutch return spring with a traction/
rotation combined action and place the belt in the
smaller diameter rolling position.

- Remove the driven pulley /belt unit from the tool.

N.B.
DURING THE SPRING PRELOADING PHASE, BE CARE-

FUL NOT TO DAMAGE THE PLASTIC SPRING STOP AND
THE BUSHING THREADING.

N.B.
FOR DESIGN REASONS, THE NUT IS SLIGHTLY ASYM-

METRIC; THE FLATTEST SURFACE SHOULD BE MOUN­TED IN CONTACT WITH THE CLUTCH.

Specific tooling

ENG - 80

LX 125 - 150 4tempi Engine

020444Y Tool for fitting/ removing the driven
pulley clutch

020444Y011 adapter ring
020444Y009 46x55 Wrench

Locking torques (N*m)

Nut locking clutch unit on pulley 55 ÷ 60 Nm

Refitting the driven pulley

- Reassemble the clutch bell and spacer.

Drive-belt

During the wear checks foreseen in the scheduled
maintenance services at 6,000 km; 18,000 km;
etc., check that the rim bottom of the toothing does
not show signs of incisions or cracking (see figure):
The rim bottom of the tooth must not have incisions
or cracking; if it does, change the belt.

- Check that the driving belt is not damaged.

- Check the width of the belt.

BELT SIZE

Specification

Minimum width 21.5 mm
Standard width 22.5 ± 0.2 mm

Desc./Quantity

ENG - 81

Engine LX 125 - 150 4tempi

Removing the driving pulley

- Lock the driving pulley with the specific tool as
shown in the figure. - Disassemble the central nut
and the Belleville washer, remove the drive and
the 2 washers. - Remove the stationary half pulley
and the steel washer.

Specific tooling

020368Y driving pulley lock wrench

- Remove the belt and slide the movable half-pul­ley with the relevant bush, taking care of the falling
free assembled rollers.

- Remove the return rollers plate with the relative
guide pads.

Inspecting the rollers case

- Check that the internal bushing is not abnormally worn and measure inner diameter.

N.B.

DO NOT LUBRICATE OR CLEAN THE BUSHING.

BUSHING ROLLER CONTAINER

Specification

Maximum allowable diameter Ø 26.121 mm

Standard diameter Ø 26+0 +0.021 mm

BUSH SLIDE PULLEY

Specification

Minimum diameter permitted Ø 25.950 mm

Standard diameter Ø 26-0.020 -0.041 mm

Desc./Quantity

Desc./Quantity

ENG - 82

VARIABLE SPEED ROLLERS

Specification

Minimum diameter permitted Ø 18.5 mm

Standard diameter Ø 26±0.1 mm

Desc./Quantity

LX 125 - 150 4tempi Engine

- Check the guide shoes for the variator back-plate
are not worn.

- Check there is no wear in the roller housing, and
the surfaces in contact with the belt on either of the
pulley halves.

Refitting the driving pulley

- Reassemble the parts of the unit (internal lining,
fixed half-pulley, external lining, drive and nut),
spread threadlock on the thread and screw the nut
to the prescribed torque.

-Avoid the half-pulley rotation using a calliper
spanner

N.B.
REPLACE THE NUT WITH A NEW ONE AT EVERY REFIT

Specific tooling

020368Y driving pulley lock wrench

Recommended products

Loctite 243 Medium strength threadlock

Loctite 243 medium-strength threadlock

Locking torques (N*m)

Locking torque 75 ÷ 83

ENG - 83

Engine LX 125 - 150 4tempi

Refitting the transmission cover

- Check the presence of the 2 centring dowels and
the correct installation of the sealing gasket for the
oil sump on the transmission cover.

- Replace the cover tightening the 10 screws at the
specified torque.

- Refit the oil loading cap/bar.

- refit the steel washer and the driven pulley nut.

- Tighten the nut to the prescribed torque using the
lock wrench and the torque wrench tools.

- Replace the plastic cover.

Specific tooling

020423Y driven pulley lock wrench

Locking torques (N*m)

Transmission cover screws 11 ÷ 13 Driven pul­ley shaft nut 54 ÷ 60

End gear

Removing the hub cover

- Empty the rear hub through the oil drainage tap
located inside the hub cover

- Remove the brake shoe and relevant spring

- Remove the 7 flanged screws as shown in the
figure.

- Remove the rubber cover and the brake pad lever
sliding unscrewing the relevant retaining screw to
reach the rear of the cover

- Take off the hub cover and relevant gaskets

ENG - 84

LX 125 - 150 4tempi Engine

Removing the wheel axle

Remove the intermediate gear and the complete
hub cover.

Removing the hub bearings

- Check the state of the bearings being examined
(wear, clearance and noisiness). If faults are de­tected, do the following.

- Use the specific bearing extractor to remove the
three 15 mm bearings (2 in the crankcase and 1 in
the hub cover).

Specific tooling

001467Y009 Driver for OD 42-mm bearings
001467Y013 Pliers to extract ø 15-mm bearings

Removing the wheel axle bearings

- Take out the clip on the outside of the gearbox
cover.

- Remove the bearing with the adequate tools ad­equately supporting the hub cover, as shown in the
figure.

Specific tooling

020376Y Adaptor handle
020364Y 25-mm guide

ENG - 85

Engine LX 125 - 150 4tempi

With the appropriate tools, remove the oil seal as
shown in the figure.

Specific tooling

020376Y Adaptor handle
020359Y 42x47-mm adaptor

Removing the driven pulley shaft bearing

If it is necessary to remove the driven pulley shaft, from the relevant bearing and oil seal, remove driven
pulley.

- Extract the driven pulley shaft from its bearing.

- Remove the oil guard using a screwdriver, working from inside the bearing and being careful not to
damage the housing, make it come out of the belt transmission side.

- Remove the seeger ring shown in the figure
With the sectional punch, remove the driven pulley

shaft bearing.

Specific tooling

020376Y Adaptor handle
020375Y Adaptor 28 x 30 mm
020363Y 20 mm guide

See also

Removing the driven pulley

Inspecting the hub shaft

- Check the three shafts for wear or distortion of
the toothed surfaces, the bearing housings, and
the oil seal housings.

- In case of anomalies, replace the damaged com­ponents.

ENG - 86

LX 125 - 150 4tempi Engine

Inspecting the hub cover

- Check that the fitting surface is not dented or distorted. - Check the capacity of the bearings and the
brake camshaft. - If faults are found, replace the hub cover.

Refitting the driven pulley shaft bearing

- Heat up the parts using the specific heat gun

Specific tooling

020150Y Air heater support
020151Y Air heater

- Reassemble the driven pulley axle bearing positioning it with ball bearing in view from the inside of
the hub cover using the adequate tools

Specific tooling

020376Y Adaptor handle

- Refit the Seeger ring with the opening facing the
bearing as shown in the figure and fit a new oil
guard flush with the crankcase.

Refitting the wheel axle bearing

- Heat up the parts using the specific heat gun

Specific tooling

020151Y Air heater
020150Y Air heater support

-The wheel axle bearing on the cover, should be assembled with the specific tools

Specific tooling

020364Y 25-mm guide
020360Y Adaptor 52 x 55 mm
020376Y Adaptor handle

ENG - 87

Engine LX 125 - 150 4tempi

•

Assemble the Seeger ring.

•

Assemble the oil seal flush with the in­ternal surface as shown in the figure to
the hub using the adequate tools and
with the seal lip towards the inside of
the hub.

Specific tooling

020376Y Adaptor handle
020360Y Adaptor 52 x 55 mm

Refitting the hub cover bearings

- For the fitting of the hub box bearings the engine crankcase and the cover must be heated with the

specific heat gun.

Specific tooling

020150Y Air heater support
020151Y Air heater

- The three 15 mm bearings must be fitted using
the appropriate tools.

Refitting the hub bearings

- Insert the cover prepared in the crankcase taking
care of inserting the gear of the pulley shaft on the
intermediary gear.

ENG - 88

LX 125 - 150 4tempi Engine

Refitting the ub cover

- Fit a new gasket together with the centring dow­els.

- Fit the gearbox cover, making sure the breather
pipe is in the correct position.

- Screw the 7 screws to the specified torque, po­sitioning the support plate of the pipe in the posi­tion shown in the figure.

Locking torques (N*m)

Locking torque 24 ÷ 27

Flywheel cover

Cooling hood

-Remove the housing acting on the 4 retaining
screws.

CAUTION
DURING REMOVAL SLIDE THE HOUSING CONNECTOR

ON THE HOUSING.

- Loosen the clamp and remove the carburettor
from the manifold.

-Remove the complete manifold acting on the 2
retainers as shown in the figure.

- Remove the 2 self threading screws, left and right
and the lateral base retaining screw on the crank­case base.

- Take off the housings.

- Remove the gasket seal of the housing on the
head.

N.B.
IF THE FLYWHEEL HOUSING IS NOT REMOVED, IT IS AL-

SO NECESSARY TO REMOVE THE TWO KNOB SCREWS.

On the vehicles equipped with the engines mentioned if they are losing a full circle at full gas, we suggest
to intervene on the vacuum socket inserting on the inlet manifold widening the hole from 0.4 mm to 1.5

ENG - 89

Engine LX 125 - 150 4tempi

mm. Remember that such operation must have performed on a disassembled manifold which must be
cleaned afterwards.

Cooling fan

- Refit the parts in reverse order of the removal
operation.

- Make sure that there are spacers with the two
rear retainers of the housing.

- The long spacers should be in a high position.

CAUTION
TAKE CARE TO CORRECTLY POSITION THE FLYWHEEL

CONNECTOR.

- Remove the cooling fan by acting on the three
fixings indicated in the figure.

Removing the stator

- Remove the electric terminal of the minimum oil
pressure switch.

- Remove the two Pick-Up screws and the one for
the wiring harness bracket as well as the two stator
fixing screws shown in the figure.

- Remove the stator and its wiring.

ENG - 90

LX 125 - 150 4tempi Engine

Refitting the stator

- Refit the stator and flywheel carrying out the re­moval procedure in reverse, tightening the retain­ers to the specified torque.

- Place the cable harness as shown in the figure.

N.B.
THE PICK-UP WIRE SHOULD BE POSITIONED BETWEEN

THE UPPER SCREW AND THE REFERENCE PIN AS
SHOWN IN THE DETAIL DRAWING.

Locking torques (N*m)

Stator screw 3 ÷ 4

Flywheel and starting

Removing the flywheel magneto

- Lock the rotation of the flywheel using the calliper
spanner.

- Remove the nut.

CAUTION
THE USE OF A CALLIPER SPANNER OTHER THAN THE

ONE SUPPLIED COULD DAMAGE THE STATOR COILS

Specific tooling

020565Y Flywheel lock calliper spanner

- Extract the flywheel with the extractor.

Specific tooling

008564Y Flywheel extractor

ENG - 91

Engine LX 125 - 150 4tempi

Inspecting the flywheel components

- Check the integrity of the internal plastic parts of the flywheel and the Pick-Up control plate.

Refitting the flywheel magneto

- Fit the flywheel being careful to insert the key
properly.

- Lock the flywheel nut to the prescribed torque

- Check that the Pick-Up air gap is between 0.34
÷ 0.76 mm.
The air gap cannot be modified when assembling
the Pick-Up.
Different values result from deformations visible
on the Pick-Up support.

N.B.
A VARIATION IN THE AIR GAP DISTANCE MODIFIES THE

IGNITION SYSTEM IDLE SPEED

Locking torques (N*m)

Flywheel nut 52 ÷ 58

Refitting the starter motor

- Fit a new O-ring on the starter and lubricate it.

- Fit the starter on the crankcase, locking the two
screws to the prescribed torque.

N.B.
REFIT THE REMAINING PARTS AS DESCRIBED IN THE

CYLINDER HEAD, TIMING, LUBRICATION, FLYWHEEL
AND TRANSMISSION CHAPTERS.

Locking torques (N*m)

Starter motor screws 11 ÷ 13

Cylinder assy. and timing system

ENG - 92

LX 125 - 150 4tempi Engine

Removing the timing system drive

- Remove the parts listed below first: transmission
cover, belt driving pulley, oil pump pulley cover and
pinion separator washer.

- Remove the tappet cover.

- Remove the central screw fastener and the au­tomatic valve-lifter retaining cover, as shown in the
figure.

- Remove the return spring of the automatic valve
lifter assembly and the automatic valve lifter as­sembly and its end of stroke washer.

- Loosen the central screw on the tensioner first.

- Remove the two fixings shown in the figure.

- Remove the tensioner with its gasket.

- Remove the internal hex screw and the counter­weight shown in the figure.

- Remove the camshaft command pulley and its
washer.

- Remove the command sprocket wheel and the
timing chain.

- Remove the screws indicated in the figure, the
spacer bar and the tensioner pad.
The chain tensioning pad must be removed from
the transmission side. As regards the lower chain
guide pad, it may only be removed after the head
has been removed.

N.B.
IT IS ADVISABLE TO MARK THE CHAIN IN ORDER TO EN-

SURE THAT THE INITIAL DIRECTION OF ROTATION IS
MAINTAINED.

See also

Transmission cover

Removing the driving pulley
Removal

ENG - 93

Engine LX 125 - 150 4tempi

Removing the cam shaft

- Remove the two screws and the cam shaft re­tainer shown in the diagram.

- Remove the cam shaft.

- Remove the pin of the rocking levers from the
flywheel side holes.

- Remove the rocking levers and the elastic wash­er.

N.B.
MARK THE ROCKING LEVERS ASSEMBLE POSITION, SO

AS TO AVOID THE INVERSION OF INLET WITH THE OUT­LET.

Removing the cylinder head

- Remove the spark plug.

- Remove the 2 side fixings shown in the figure.

- Loosen the 4 head-cylinder fastening nuts in two
or three stages and in criss-cross fashion.

- Remove the head, the two centring dowels and
the gasket.

N.B.
IN CASE OF NEED, THE HEAD MAY BE REMOVED WITH

THE CAMSHAFT, PINS, ROCKING LEVERS AND FIXING
BRACKET. THE HEAD CAN ALSO BE REMOVED WITH­OUT REMOVING THE CHAIN AND THE DRIVING SHAFT
CHAIN TIGHTENER.

ENG - 94

LX 125 - 150 4tempi Engine

Removing the valves

- Using the specific tool fitted with the element
shown in the figure, remove the cotters, the plates
and the spring between the valves.

Specific tooling

020382Y Valve cotters equipped with part 012
removal tool

020382Y011 adapter for valve removal tool

- Remove the oil seals with the appropriate tool.

- Remove the lower spring supports.

Specific tooling

020431Y Valve oil seal extractor

Removing the cylinder - piston assy.

- Remove the chain guide pad.

- Remove the cylinder base gasket.

CAUTION
TO AVOID DAMAGING THE PISTON, SUPPORT IT WHILE

REMOVING THE CYLINDER.

- Remove the two stop rings, the wrist pin and the
piston.

- Remove the 3 piston rings from the piston.

N.B.
BE CAREFUL NOT TO DAMAGE THE PISTON RINGS DUR-

ING REMOVAL.

ENG - 95

Engine LX 125 - 150 4tempi

Inspecting the small end

- Measure the internal diameter of the small end
using an internal micrometer.

N.B.
IF THE DIAMETER OF THE ROD SMALL END EXCEEDS

THE MAXIMUM DIAMETER ALLOWED, SHOWS SIGNS OF
WEAR OR OVERHEATING REPLACE THE CRANKSHAFT
AS DESCRIBED IN THE "CRANKCASE AND CRANK­SHAFT" CHAPTER".

Characteristic

Rod small end check-up: Maximum diameter

15.030 mm

Rod small end check-up: Standard diameter

15 +0.015+0.025 mm

Inspecting the wrist pin

- Check the outer diameter of the gudgeon pin.

Characteristic

Standard pin diameter

14.996 ÷ 15 mm

Minimum diameter permitted

Ø 14.994 mm

- Calculate the piston pin coupling clearance.

N.B.
THE PIN HOUSINGS HAVE 2 LUBRICATION CHANNELS.

FOR THIS REASON MEASUREMENT OF THE DIAMETER
MUST BE CARRIED OUT ACCORDING TO THE AXIS OF
THE PISTON.

Characteristic

Piston pin bore - standard diameter

Ø 15+0.001 +0.006

ENG - 96

LX 125 - 150 4tempi Engine

- Measure the outside diameter of the piston, per­pendicular to the gudgeon pin axis.

- Measure 36.5 mm from the piston crown's shown
in the figure.

N.B.
THE PIN HOUSINGS HAVE 2 LUBRICATION CHANNELS.

FOR THIS REASON MEASUREMENT OF THE DIAMETER
MUST BE CARRIED OUT ACCORDING TO THE AXIS OF
THE PISTON.

- Using a bore meter, measure the inner cylinder
diameter at three different points according to the
directions shown in the figure.

- Check that the coupling surface with the head is
not worn or misshapen.

- Pistons and cylinders are classified into catego­ries based on their diameter. The coupling is car­ried out in pairs (A-A, B-B, C-C, D-D).

Characteristic

Maximum allowable run-out:

0.05 mm

- The cylinder rectifying operation should be car­ried out with a surfacing that respects the original
angle.

- The cylinder surface roughness should be 0.9
micron.

- This is indispensable for a good seating of the
sealing rings, which in turn minimises oil consump­tion and guarantees optimum performance.

- The pistons are oversized due to cylinder rectifi­cation and are subdivided into three categories
1st, 2nd, 3rd with 0.2-0.4-0.6 mm oversize. They
are also classified into 4 categories A-A, B-B, C­C, D-D.

Inspecting the piston

- Carefully clean the seal housings.

- Measure the coupling clearance between the seal rings and the grooves using suitable sensors, as
shown in the diagram.

- If the clearance is greater than that indicated in the table, replace the piston.

ENG - 97

Engine LX 125 - 150 4tempi

STANDARD COUPLING CLEARANCE

Name Description Dimensions Initials Quantity

Top piston ring 0.025 ÷ 0.070

Middle piston ring 0.015 ÷ 0.060

oil scraper 0.015 ÷ 0.060

MAXIMUM ADMITTED CLEARANCE AFTER USE

Name Description Dimensions Initials Quantity

Top piston ring 0.080 mm

Middle piston ring 0.070 mm

oil scraper 0.070 mm

Removing the piston

- Install piston and wrist pin onto the connecting
rod, aligning the piston arrow the arrow facing to­wards the exhaust.

- Fit the pin stop ring onto the appropriate tool.

Specific tooling

020430Y Pin lock fitting tool

- With the opening in position indicated on the tool,
take stop ring in the closed position using the
punch.

- Fit the wrist pin stop using the plug as shown in
the figure

N.B.
THE TOOL FOR INSTALLING THE STOP RINGS MUST BE

USED MANUALLY.
CAUTION
USING A HAMMER TO POSITION THE RINGS CAN DAM-

AGE THE LOCKING HOUSING.

ENG - 98

LX 125 - 150 4tempi Engine

Refitting the piston rings

- Place the oil scraper spring on the piston.

- Refit the oil scraper ring with the join of spring
ends on the opposite side from the ring gap and
the word 'TOP' towards the crown of the piston.
The tapered side of the middle piston ring should
always be facing away from the crown of the pis­ton.

- Fit the middle piston ring with the identification
letter facing the crown of the piston. In any case,
the step must be facing opposite the piston top.

- Fit the top piston ring with the word 'top' or the
reference mark facing the crown of the piston.

- Offset the piston ring gaps on the three rings by
120° to each other as shown in the figure.

- Lubricate the components with engine oil.

N.B.
SO AS TO OBTAIN THE BEST CONFIGURATION THE 2

SEALING RINGS ARE MADE WITH A CONTACT CONICAL
CYLINDER SECTION.

Refitting the cylinder

- Insert the cylinder base gasket with the thickness
determined above.

- Using the fork support and the piston ring retain­ing band, refit the cylinder as shown in the figure.

N.B.
BEFORE FITTING THE CYLINDER, CAREFULLY BLOW

OUT THE LUBRICATION DUCT AND OIL THE CYLINDER
BARREL.

Specific tooling

020426Y Piston fitting fork

ENG - 99

Engine LX 125 - 150 4tempi

020427Y Piston fitting band

Inspecting the cylinder head

- Using a trued bar check that the cylinder head
surface is not worn or distorted.

- Check that the camshaft and rocking lever pin
bearings show no signs of wear.

- Check that the cylinder head cover surface, the
intake manifold and the exhaust manifold are not
worn.

Characteristic

Maximum admitted unevenness: Head check

0.05 mm

STANDARD DIAMETER

Specification Desc./Quantity

Standard diameter A Ø 32.5 ÷ 32.525
Standard diameter B Ø 20 ÷ 20.021
Standard diameter C Ø 12 ÷ 12.018

Inspecting the timing system components

- Check that the guide shoe and the tensioner shoe
are not worn out.

- Ensure that the camshaft drive pulley, the chain
assembly and the sprocket wheel are not worn.

- If sings of wear are found, replace the parts. if the
chain, pinion or pulley are worn, replace the whole
assembly.

ENG - 100