Gilera Nexus 500SP Mk2 Workshop Workshop Manual

WORKSHOP MANUAL

633721 - 633728

Nexus 500 euro 3

WORKSHOP

MANUAL

Nexus 500 euro 3

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 shown in this publication are available in all Countries. The availability of single versions

should be checked at the official Piaggio sales network.

"© Copyright 2005 - 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. - Q.C.S./After sales V.le Rinaldo Piaggio, 23 - 56025 PONTEDERA (Pi)

www.piaggio.com

WORKSHOP MANUAL

Nexus 500 euro 3

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 scooter mounting techniques and procedures. Any
important changes made to the scooters or to specific mounting operations will be promptly reported by
updates to this manual. Nevertheless, no mounting 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 special
tools, along with the special 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

ELECTRICAL SYSTEM ELE SYS

ENGINE FROM VEHICLE ENG VE

ENGINE ENG

INJECTION INJEC

SUSPENSIONS SUSP

BRAKING SYSTEM BRAK SYS

COOLING SYSTEM COOL SYS

CHASSIS CHAS

PRE-DELIVERY PRE DE

TIME TIME

INDEX OF TOPICS

CHARACTERISTICS CHAR

Characteristics Nexus 500 euro 3

This section describes the general specifications of the vehicle.

Rules

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

Safety rules

•

Should it be necessary to keep the engine running while servicing, make sure that the area
or room is well ventilated, and use special exhaust fans, if required. 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 in some conditions it can be explosive. Do not smoke in the
working area, and avoid open flames or sparks.

•

Clean the brake pads in a well ventilated environment, directing the compressed air jet so
as to not inhale the dust produced by the wear of the friction material. Even though the latter
contains no asbestos, dust inhalation is harmful.

Maintenance rules

•

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

•

Use only the special tools designed for this scooter.

•

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

•

After removal, clean the components using non-flammable or low fire-point solvent. Lubri­cate all the work surfaces except the tapered couplings before reassembly.

•

After reassembly, check that all components have been installed properly and that they are

•

•

CHAR - 2

in good working order.
For removal, overhaul and reassembly operations use only tools provided with metric meas­ures. Metric bolts, nuts and screws are not interchangeable with coupling members with
English measurement. Using unsuitable coupling members and tools may damage the
scooter.
Should any interventions to the scooter electrical system be required, check that the elec­trical connections - especially earth and battery connections - have been implemented
properly.

Nexus 500 euro 3 Characteristics

Vehicle identification

Characteristic

Engine prefix:

M351M

Chassis prefix:

ZAPM35200

Dimensions and mass

Specification Desc./Quantity

Dry weight 199 kg

Width 765 mm

Length 2090 mm

Wheel base 1515 mm

Saddle height 780 mm

Height 1045 mm

WEIGHT

CHAR - 3

Characteristics Nexus 500 euro 3

Engine

ENGINE

Specification Desc./Quantity

Engine single-cylinder four stroke

Bore 92 mm

Stroke 69 mm

Cubic capacity 460 cm³

Compression ratio 10.5: 1

Timing system Single overhead camshaft with integrated tone

wheel, control from flywheel side chain, 4 valves

and automatic start-up valve lifting device.

Valve clearance: intake: 0.15 mm (when cold)

Valve clearance: exhaust 0.15 mm (when cold)

Valve clearance adjustment By threaded adjuster on the rockers

Engine idle speed 1500 ± 50 rpm

Air filter sponge, impregnated with mixture (50% petrol and

50% oil)

CO % value (measured at the intake manifold) 1 ÷ 1.5%

Starting system Electric starter system with freewheel.

Lubrication By trochoidal pump (inside the crankcase), pres-

sure adjustment by-pass and oil filter.

Lubrication pressure 4 bar

Minimum allowed (at 100° C) 0.8 bar

Fuel supply Electronic injection system with electric fuel pump,

Ø 38 mm throttle body and single injector.
Max. power (shaft) 29 kW (39 CV) at 7250 rpm
Max. torque (shaft) 40 N·m (4 kgm) at 5500 rpm

Cooling system Fluid circulation through a motor-driven pump, 3-

way thermostat and electric fan.

Transmission

TRANSMISSIONS

Specification Desc./Quantity

Transmission With automatic expandable pulley variator with tor-

que server, V belt, automatic clutch, gear reduc-

tion unit and transmission housing with forced air

circulation cooling.

Capacities

CAPACITY

Specification Desc./Quantity

Engine oil (dry) ~ 1.7 litres

Engine oil (at oil and filter change) approx. 1.5 litres

Fuel tank (including reserve approx. 2 litres) approx. 14.5 litres

Rear hub approx. 250 cc.

Cooling system approx. 1.8 litres

Front fork approx. 242 ± 3 cc (in each fork leg)

CHAR - 4

Nexus 500 euro 3 Characteristics

Electrical system

ELECTRICAL SYSTEM

Specification Desc./Quantity

Electronic ignition inductive, high efficiency integrated with the injec-

tion system, with variable timing and separate HV

coil.
Spark plug NGK CR7EKB
Spark plug CHAMPION RG6YC

Battery Dry-cell lead-acid battery, 12V-14Ah

Generator Three-phase alternating current

Frame and suspensions

CHASSIS AND SUSPENSIONS

Specification Desc./Quantity

Chassis Welded tubular steel chassis with stamped sheet

reinforcements

Front suspension Hydraulic telescopic fork with diameter 41 mm

stems

Max. front fork travel 104 mm

Rear suspension Type "Power drive": Shock absorber (with double-

acting helicoidal spring and adjustment of the
spring preload in 7 positions) mounted in horizon­tal position, connected to a connecting rod pivoted

to a strut with variable length.

By varying the length of the strut it is possible to

modify the geometry and balance of the rear axle

(15 positions).

The motor has a fixed connection to the frame by

means of a shaft (direct link).

Brakes

Specification Desc./Quantity

Front brakes Twin discs of stainless steel, dia. 260 mm, with

Rear brakes Disc of stainless steel, dia. 240 mm, with fixed cal-

Wheels and tyres

Specification Desc./Quantity

Rims in light alloy: Front 3.50 x 15"

BRAKES

floating calliper and twin 28 mm diameter plungers

(Brembo) at front right and twin 26 mm diameter

plungers (Brembo) at front left.

liper and two opposed 34 mm diameter plungers

WHEELS AND TYRES

CHAR - 5

Characteristics Nexus 500 euro 3

Specification Desc./Quantity

Rims in light alloy: Rear 4.50 x 14"

Rear tyres Bridgestone 160/60-R14" Tubeless 65H

Front tyres Bridgestone 120/70-R15" Tubeless 56H

Tyre pressure (cold) front 2.1 bar

Tyre pressure (cold) rear 2.3 bar (2.5 bar with passenger)

N.B.

CHECK AND ADJUST TYRE PRESSURE WITH TYRES AT AMBIENT TEMPERATURE. ADJUST
PRESSURE ACCORDING TO THE WEIGHT OF THE RIDER AND ACCESSORIES.

CAUTION

IT IS MANDATORY TO ADOPT EXCLUSIVELY "S" CLASS TYRES, WHICH GUARANTEE COR­RECT VEHICLE PERFORMANCE AT THE DIFFERENT SCOOTER SPEEDS. USING ANY OTHER
TYRE MAY RESULT IN VEHICLE INSTABILITY. IT IS ADVISABLE TO USE TYRE TYPES REC­OMMENDED BY PIAGGIO.

Tightening Torques

FRAME

Name Torque in Nm

Electric pump locking ring nut 20

BRAKE SYSTEM

Name Torque in Nm

Brake calliper coupling 20 - 24

Front brake disc mounting 5 ÷ 6 •

Rear brake disc mounting 11 ÷ 13

Front brake calliper mounting on fork 20 ÷ 25

Rear calliper support clamp to crankcase 20 ÷ 25

Pipe joint / brake calliper 20 ÷ 25

Circuit bleed calliper fitting 12 - 16

Plastic protection retaining screw 5 - 6

Coupling for oil on the integral braking system

pump

Coupling on the integral braking system device

(from the pump)

Front brake calliper - integral braking system de-

vice coupling

Rear brake calliper - integral braking system de-

vice coupling

• Locking with Loctite threadlock medium 243

16 ÷ 20
20 ÷ 25
20 ÷ 25
20 ÷ 25

FRONT SUSPENSION

Name Torque in Nm

Front wheel shaft 45 ÷ 50

Holding torque of lower ring nut 20 ÷ 25

Fork stem mounting to the plate 20 ÷ 25

Lower steering ring nut 10 - 13 **
Upper steering ring nut 36 - 39

Stem upper cap 35 - 55

Screw securing handlebar to steering tube 45 - 50

CHAR - 6

Nexus 500 euro 3 Characteristics

Name Torque in Nm

Pumping element fixing screw 25 - 35

Safety screw on fork leg 6 ÷ 7

Wheel fastening screws 33 - 37

* Tighten and loosen completely. ** Tighten and loosen by 90°

REAR SUSPENSION

Name Torque in Nm

Engine - chassis fixing pin 100 - 120

Central stand retainers 25 - 30

Muffler heat guard retainers 6 - 8

Side stand clamp 15 ÷ 20

Rear wheel axle 104 ÷ 126

Connection of rear shock absorber to support con-

necting rod

Rear shock absorber retainer to the chassis 38 - 46

Upper strut connection 56 - 70

Clamping of connection rod supporting strut and

shock absorber to frame

Clamping of rear strut support to hub cover 20 - 25

Lower strut clamping 30 - 35

Rear strut support clamping to crankcase 11 - 13

Assembly plate mounting on strut support 11 - 13

• Locking with Loctite threadlock medium 243

38 - 46

73 - 80

ENGINE ASSEMBLY

Name Torque in Nm

Starter motor screws 11 ÷ 13

THERMAL UNIT AND TIMING SYSTEM

Name Torque in Nm

Spark plug 12 ÷ 14

Head fixing stud bolts: ***

Head fixing nuts 10 - 12

Exhaust / intake head fixing nuts: 10 - 12

Head lubrication control jet 5 - 7

coolant temperature sensor: 10 - 12

Lambda probe on exhaust manifold 10 - 12

injector fixing screw 3 ÷ 4

Counterweight screw 7 ÷ 8.5

Tensioner sliding block fixing screw: 10 - 14

Rpm timing sensor fixing screw: 3 - 4

Valve lifter mass stop bell fixing screws: 30 - 35

Inlet manifold screws 11 ÷ 13

Tappet cover fixing screws: 7 - 9

Throttle body fixing screws 11 ÷ 13

Head fixing screws 10 - 12

Camshaft retaining bracket screws: 4 ÷ 6

Tightener screw: 5 - 6

Tightener fastening screws: 11 ÷ 13

*** Apply a preliminary torque of 7 N·m in a crossed sequence. - Tighten by 90° in a crossed sequence. - Tighten again by 90°
in a crossed sequence.

CHAR - 7

Characteristics Nexus 500 euro 3

CRANKCASE AND CRANKSHAFT

Name Torque in Nm

Countershaft fixing nut 25 - 29

Engine oil filter 12 - 16

Engine oil drainage plug 24 ÷ 30

Engine-crankcase coupling screws 11 ÷ 13

Oil pump screws 5 - 6

Gear mounting on crankshaft screws 10 -12

Bulkhead screws for oil pump housing cover 8 - 10

FINAL REDUCTION

Name Torque in Nm

Rear hub cover screws 24 ÷ 27

TRANSMISSION COVER

Name Torque in Nm

Driven pulley nut 92 - 100

Drive pulley nut 160 - 175

Anti-vibration roller screw 16.7 - 19.6

M8 retainers for transmission cover 23 - 26

M6 retainer 11 ÷ 13

Anti-vibration roller retainer 17 - 19

Clutch ring nut 65 - 75

Air conveyor screws 11 ÷ 12

Water pump cover screws 3 ÷ 4

Outside transmission cover screws 7 ÷ 9

Flywheel cover screws 11 - 13

FLYWHEEL COVER

Name Torque in Nm

Chain guide sliding block retain plate fastening

screws

Flywheel fixing nut 115 - 125

Stator retainers 8 - 10

Blow-by recovery duct fixing screws 3 - 4

Screw fixing freewheel to flywheel 13 ÷ 15

Stator cable harness guide bracket screws 3 - 4

Supporting screws with bulkhead 0.3 - 0.4

Minimum oil pressure sensor 12 ÷ 14

Water pump impeller 4 ÷ 5

LUBRICATION

Name Torque in Nm

Oil pump cover screws 0.7 ÷ 0.9

Screws fixing oil pump to the crankcase 5 - 6

See also

Refitting
Refitting
Fuel tank
Overhaul

3 ÷ 4

CHAR - 8

Nexus 500 euro 3 Characteristics

Overhaul data

This section provides the main information for scooter servicing.

Assembly clearances

Cylinder - piston assy.

(Values in mm)

HEIGHT AT WHICH THE DIAMETER SHOULD BE MEASURED

Specification Desc./Quantity

A: 10 mm
B: 43 mm

CATEGORIES OF COUPLING

Name Initials Cylinder Piston Play on fitting

Cylinder Piston A 91.990 - 91.997 91.954 - 91.961 0.029 - 0.043
Cylinder Piston B 91.997 - 92.004 91.961 - 91.968 0.029 - 0.043
Cylinder Piston C 92.004 - 92.011 91.968 - 91.975 0.029 - 0.043
Cylinder Piston D 92.011 - 92.018 91.975 - 91.982 0.029 - 0.043

N.B.

THE PISTON MUST BE INSTALLED WITH THE ARROW FACING TOWARDS THE EXHAUST SIDE,
THE PISTON RINGS MUST BE INSTALLED WITH THE WORD «TOP» OR THE STAMPED MARK
FACING UPWARDS.

Piston rings

CHAR - 9

Characteristics Nexus 500 euro 3

* Fit rings «2» and «3» with the word «TOP» facing upwards.
** Position the openings in the rings as shown here.
*** Value «A» of sealing ring inside the cylinder
**** Ring opening

SEALING RINGS

Name Initials Cylinder Piston Play on fitting

1st Compression

ring

Middle piston ring A 0.25 ÷ 0.50 0.65 </>

Oil scraper ring A 0.25 ÷ 0.50 0.65 </>

A 0.15 ÷ 0.35 0.5 </>

Crankcase - crankshaft - connecting rod

Crankcase / countershaft coupling

Besides considering it should match the crankshaft, the crankcase is chosen according to the centre
to centre distance between the seat of the crankshaft and that of the contra-rotating shaft.
Both the centre to centre distance and the pair of gears driving the contra-rotating shaft are divided into
two types (A and B) to be matched (A with A and B with B).
This selection is useful to keep the difference between the working distance of the gears and their
distance without clearance at a given value in order to avoid abnormal noise.

TYPE A

Specification Desc./Quantity

Centre to centre distance of the gears without

clearance

Centre to centre distance on the crankcase 77.022 ÷ 76.992

76.937 ÷ 76.867

TYPE B

Specification Desc./Quantity

Centre to centre distance of the gears without

clearance

Centre to centre distance on the crankcase 76.992 ÷ 76.962
The gears with centre to centre distance without clearance between 76.867 and 76.907 are considered
universal and can be fitted to either crankcase type.
Either the pair of gears or the crankcase is identified with the letter referring to the type (on the crank-

76.907 ÷ 76.837

case, this mark is found at the cylinder mouth, flywheel side).

CHAR - 10

Nexus 500 euro 3 Characteristics

Diameter of crankshaft bearings.

Measure the capacity on both axes x-y.

CRANKSHAFT

Specification Desc./Quantity

Cat. 1 Standard diameter: 40.010 ÷ 40.016
Cat. 2 Standard diameter: 40.016 ÷ 40.022

Crankshaft alignment

Specific tooling

020335Y Magnetic support for dial gauge

MAX. ADMISSIBLE DISPLACEMENT

Specification Desc./Quantity

A = 0.15 mm
B = 0.010 mm
C = 0.010 mm
D = 0.10 mm

CHAR - 11

Characteristics Nexus 500 euro 3

AXIAL CLEARANCE BETWEEN CRANKSHAFT AND CONNECTING ROD

Name Description Dimensions Initials Quantity

Transmission-side

shoulder

Transmission-side

half-shaft

Connecting rod 22 0.10-0.15 C D= 0.20 - 0.40

Flywheel-side

shoulder

Flywheel-side half-

shaft

Complete drive

shaft

0.8 ± 0.025 A D= 0.20 - 0.40

19.6 + 0.050 B D= 0.20 - 0.40

13 ± 0.025 F D= 0.20 - 0.40

19.6 +0.050 E D= 0.20 - 0.40

63.5+0.1-0.05 G D= 0.20 - 0.40

Characteristic

Drive shaft / crankcase axial clearance:

0.1 - 0.5 mm (when cold)

CHAR - 12

Nexus 500 euro 3 Characteristics

Slot packing system

Shimming system for limiting the compression ra­tio Rc = 10.5 : 1

DISTANCE «A» IS A PROTRUSION OR RE­CESS VALUE OF THE PISTON CROWN WITH
RESPECT TO THE CYLINDER PLANE.
DISTANCE «A» HELPS DETERMINE THE
THICKNESS OF GASKET «B» THAT HAS TO
BE FITTED TO THE CYLINDER HEAD IN OR­DER TO RESTORE COMPRESSION RATIO.
BASE GASKET «B» MUST BE THICKER THE
MORE THE PLANE FORMED BY THE PISTON
TOP PROTRUDES FROM THE PLANE
FORMED BY THE CYLINDER HEAD. ON THE
OTHER HAND, THE MORE THE PISTON TOP IS
RECESSED INTO THE CYLINDER TOP PLANE,
THE SMALLER THE GASKET THICKNESS.

BASE GASKET THICKNESS

Name Measure A Thickness

«A» MEASURE TAKEN - 0.185 - - 0.10 0.4 ± 0.05
«A» MEASURE TAKEN - 0.10 - + 0.10 0.6 ± 0.05
«A» MEASURE TAKEN + 0.10 ÷ + 0.185 0.8 ± 0.05

N.B.

VALUES INDICATED WITH «-» REFER TO PISTON CROWN RECESSES WITH RESPECT TO THE
CYLINDER PLANE.

N.B.

DISTANCE «A» MUST BE MEASURED WITHOUT ANY GASKET FITTED AT «B»

Products

PRODUCTS

Product Description Specifications

AGIP ROTRA 80W-90 Rear hub oil SAE 80W/90 Oil that exceeds the

requirements of API GL3 specifi-

cations

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

for increased adhesiveness

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

JASO MA Synthetic oil

AGIP BRAKE 4 Brake fluid FMVSS DOT 4 Synthetic fluid

SPECIAL AGIP PERMANENT

fluid

AGIP EXTRA POLISH Muffler cleaning paste special product for cleaning and

AGIP GP 330 Grease for brake levers, throttle White calcium complex soap-

AGIP CITY TEC 2T Mixer oil synthetic oil for 2-stroke engines:

coolant Monoethylene glycol-based anti-

freeze fluid, CUNA NC 956-16

polishing stainless steel muffler

based spray grease with NLGI 2;

ISO-L-XBCIB2

JASO FC, ISO-L-EGD

CHAR - 13

Characteristics Nexus 500 euro 3

CHAR - 14

INDEX OF TOPICS

TOOLING TOOL

Tooling Nexus 500 euro 3

GOOD SPECIAL TOOLS

Stores code Description

001330Y Tool for fitting steering seats

001467Y002 Driver for OD 73 mm bearing

001467Y006 Pliers to extract 20 mm bearings

001467Y007 Driver for OD 54 mm bearing

001467Y008 Pliers to extract 17 mm ø bear-

ings

001467Y014 Pliers to extract ø 15-mm bear-

ings

TOOL - 2

Nexus 500 euro 3 Tooling

Stores code Description

001467Y031 Bell

001467Y034 Extraction pliers for ø 15 mm

bearings

001467Y035 Belle for OD 47-mm bearings

002465Y Pliers for circlips

006029Y Punch for fitting fifth wheel seat

on steering tube

020004Y Punch for removing fifth wheels

from headstock

TOOL - 3

Tooling Nexus 500 euro 3

Stores code Description

020055Y Wrench for steering tube ring nut

020150Y Air heater support

020151Y Air heater

020193Y Oil pressure gauge

020201Y Spacer bushing driving tube
020262Y Crankcase splitting strip

020306Y Punch for assembling valve seal

rings

TOOL - 4

Nexus 500 euro 3 Tooling

Stores code Description

020329Y MityVac vacuum-operated pump

020330Y Stroboscopic light for timing con-

trol

020331Y Digital multimeter

020333Y Single battery charger

020334Y Multiple battery charger

TOOL - 5

Tooling Nexus 500 euro 3

Stores code Description

020335Y Magnetic support for dial gauge

020357Y 32 x 35 mm adaptor
020358Y 37x40-mm adaptor
020359Y 42x47-mm adaptor

020360Y Adaptor 52 x 55 mm

020364Y 25-mm guide

020376Y Adaptor handle

020382Y012 bush (valve removing tool)

TOOL - 6

Nexus 500 euro 3 Tooling

Stores code Description

020412Y 15 mm guide

020424Y Driven pulley roller casing fitting

punch

020431Y Valve oil seal extractor

020434Y Oil pressure control fitting

020439Y 17 mm guide

TOOL - 7

Tooling Nexus 500 euro 3

Stores code Description

020444Y Tool for fitting/ removing the driv-

en pulley clutch

020456Y Ø 24 mm adaptor

020458Y Puller for lower bearing on steer-

ing tube

020459Y Punch for fitting bearing on steer-

ing tube

020460Y Scooter diagnosis and tester

020467Y Flywheel extractor

TOOL - 8

Nexus 500 euro 3 Tooling

Stores code Description

020468Y Piston fitting ring

020469Y Reprogramming kit for scooter

diagnosis tester

020470Y Pin retainers installation tool

020471Y Pin for countershaft timing

020472Y Flywheel lock wrench

TOOL - 9

Tooling Nexus 500 euro 3

Stores code Description

020474Y Driving pulley lock wrench

020475Y Piston position checking tool

020476Y Stud bolt set

020478Y Punch for driven pulley roller cas-

ing

020479Y Countershaft lock wrench

020480Y Petrol pressure check set

TOOL - 10

Nexus 500 euro 3 Tooling

Stores code Description

020481Y Control unit interface wiring

020482Y Engine support

020483Y 30 mm guide

020512Y Piston fitting fork

020527Y Engine support base

020604Y011 Fitting adapter

020565Y Flywheel lock calliper spanner

TOOL - 11

Tooling Nexus 500 euro 3

Stores code Description

020623Y Pre-service gas extraction set

020625Y Kit for sampling gas from the ex-

haust manifold

020640y software euro3

TOOL - 12

INDEX OF TOPICS

MAINTENANCE MAIN

Maintenance Nexus 500 euro 3

Maintenance chart

EVERY 2 YEARS

60'

Action

Coolant - change
Brake fluid - change

AFTER 1,000 KM

Action

Safety locks - check
Throttle lever - adjustment
Engine oil - change
Electrical system and battery - check
Coolant level - check
Brake fluid level - check
Engine oil - replacement
Brake pads - check condition and wear
Tyre pressure and wear - check
Vehicle and brake test - road test
Hub oil - change
Crankcase breather - empty
Steering - adjustment
Injection system pipework - visual check

AFTER 10,000 KM AFTER 30,000 KM AFTER 50,000 KM AND AFTER 70,000 KM

Action

Safety locks - check
Spark plug - replacement
Driving belt - replacement
Throttle lever - adjustment
Air filter - check
Air filter belt compartment - check
Engine oil - change
Valve clearance - check
Electrical system and battery - check
Coolant level - check
Brake fluid level - check
Engine oil - replacement
Brake pads - check condition and wear

MAIN - 2

Nexus 500 euro 3 Maintenance

Action

Sliding block / variable speed rollers - change
Tyre pressure and wear - check
Vehicle and brake test - road test
Hub oil - check
Stand control roller - replace
Suspensions - check
Steering - Check
Injection system pipework - visual check
Crankcase breather - empty

AFTER 20,000 KM AFTER 40,000 KM AFTER 60,000 KM AND AFTER 80,000 KM

Action

Safety locks - check
Bushing of driven pulley
Spark plug - replacement
Driving belt - replacement
Throttle lever - adjustment
Air filter - check
Air filter belt compartment - check
Engine oil - change
Valve clearance - check
Electrical system and battery - check
Coolant level - check
Brake fluid level - check
Engine oil - replacement
Brake pads - check condition and wear
Sliding block / variable speed rollers - change
Tyre pressure and wear - check
Vehicle and brake test - road test
Hub oil - check
Stand control roller - replace
Crankcase breather - empty
Suspensions - check
Steering - Check
Injection system pipework - visual check
Fuel filter - check

Spark plug

Check and replacement

CAUTION

THE SPARK PLUG MUST BE REMOVED WITH
COLD ENGINE. THE SPARK PLUG SHOULD
BE CHECKED EVERY 6,000 KM AND RE­PLACED EVERY 12,000 KM. THE USE OF NON­CONFORMING IGNITION CONTROL UNITS
AND SPARK PLUGS OTHER THAN THOSE
PRESCRIBED CAN SERIOUSLY DAMAGE THE
ENGINE.

Characteristic

Recommended spark plugs:

MAIN - 3

Maintenance Nexus 500 euro 3

CHAMPION RG6YC - NGK CR 7 EKB

- Position the scooter on centre stand.

- Remove the side cover on the left-hand side of the scooter, loosening the three screws shown in the
figure.

- Disconnect the shielded spark plug cap

- Unscrew the spark plug.

- Check the conditions of the spark plug, make sure the insulation is intact, that the electrodes are not
excessively worn or grimy, the conditions of the washer, and measure the distance between the elec­trodes using the appropriate feeler gauge.

Characteristic

Electrode gap

0.7-0.8 mm

Adjust the gap if necessary, carefully bending the
earth electrode. In the event of irregularity, replace
the spark plug with a recommended type.

- Fit the spark plug with the correct inclination and
manually screw it all the way down, then use the
special spanner to tighten it.

Locking torques (N*m)

Spark plug 12 ÷ 14

- Insert the cap onto the spark plug and proceed with the reassembly operations.

Hub oil

MAIN - 4

Nexus 500 euro 3 Maintenance

Check

Check the oil in the rear hub.

Characteristic

Rear hub oil

Capacity approximately 250 cc

To check the rear hub oil level, proceed as follows:

- Park the scooter on flat ground resting on its centre stand.

- Set the strut that adjusts the level to its minimum height.

- Unscrew the oil dipstick, dry it with a clean cloth and reinsert it, screwing it in thoroughly.

- Pull out the dipstick and check that the oil level is
between the MAX and MIN notches indicated on
the dipstick; if the level is below the MIN value, re­store the proper amount of oil in the hub.

-Retighten the oil dipstick again and make sure it
is locked properly into place.

Replacement

- Prepare a suitable container.

- Remove the oil filler plug shown in the figure.

MAIN - 5

Maintenance Nexus 500 euro 3

- Unscrew the oil drainage plug and drain out all
the oil.

- Tighten the drainage plug with its gasket and re­fill.

- Tighten the oil filler plug.

Characteristic

Rear hub oil

Capacity approximately 250 cc

Recommended oil:

TUTELA ZC 90

Air filter

- Raise the saddle.

- Remove the piston ring and the battery cover.

- Loosen the 4 mounting screws shown in the fig­ure.

- Loosen the mounting screw located under the intake manifold.

MAIN - 6

Nexus 500 euro 3 Maintenance

- Replace the air filter and reassemble the various
components, reversing the removal procedure.

- An inspection and possible cleaning (with com­pressed air) of the air filter is scheduled every 6000
km in any case.

- The air jet must be directed from the inside to the
outside of the filter (i.e. opposite the direction of
the air flow during normal operation of the engine).

- Any deposits of condensate out of the engine oil
caused by blow-by can be removed via the pipe
shown in the figure.

N.B.

FAILURE TO OBSERVE THE RULES REGARD­ING CLEANING OF THE FILTER ELEMENT
CAN LEAD TO IMPROPER LUBRICATION OF
THE ELEMENT. POOR LUBRICATION AF­FECTS THE FILTERING CAPACITY. EXCES­SIVE LUBRICATION AS WITH A SOILED FIL­TER CAUSES AN EXCESSIVELY RICH FUEL/
AIR MIXTURE.

CAUTION

WHEN TRAVELLING ON DUSTY ROADS, THE
AIR FILTER MUST BE CLEANED MORE OFTEN
THAN SHOWN IN THE SCHEDULED MAINTE­NANCE CHART.

WARNING

DO NOT RUN THE ENGINE IF THE AIR FILTER
IS NOT IN PLACE THIS WILL RESULT IN EX­CESSIVE WEAR TO ALL THE PARTS OF THE
COOLING SYSTEM.

Engine oil

In 4T engines, the engine oil is used to lubricate the distribution elements, the bench bearings and the
thermal group. An insufficient quantity of oil can cause serious damage to the engine.
In all 4T engines, the deterioration of the oil characteristics, or a certain consumption should be con­sidered normal, especially if during the run-in period. Consumption levels in particular can be influenced
by the conditions of use (e.g.: oil consumption increases when driving at "full throttle".

MAIN - 7

Maintenance Nexus 500 euro 3

Check

This operation must be carried out with the engine cold and following the procedure below:

1) Rest the scooter on the central stand and on a
flat ground.

2) Unscrew the cap/dipstick "A", dry it with a clean
cloth and reinsert it, screwing it thoroughly.

3) Remove the cap/dipstick again and check that
the level is between the max. and min levels; top
up, if required.
Topping up from the MIN to MAX. level requires
around 1700 cc.
If the check is carried out after the vehicle has
been used, and therefore with a hot engine, the
level line will be lower; in order to carry out a cor­rect check it is necessary to wait at least 10 mi­nutes after the engine has been stopped, so as to
get the correct level.

Oil top up
The oil should be topped up after having checked the level and in any case by adding oil without ever
exceeding the MAX. level.
The restoration level between the MIN and MAX levels implies a quantity of oil of approx. 400 cc.

Engine oil filter

CAUTION

DO NOT DISPOSE OF OIL IN THE ENVIRONMENT. OIL, GASKET AND FILTER SHOULD BE DIS­POSED OF ACCORDING TO THE REGULATIONS IN FORCE.

WARNING

AVOID TOUCHING PARTS OF THE ENGINE WHEN HOT, AS THIS MAY CAUSE BURNS.

- Remove the muffler.

- Remove the filler plug.

MAIN - 8

Nexus 500 euro 3 Maintenance

- Remove and clean the mesh pre-filter of the drain
cap with compressed air.

- Use a belt spanner for filters to remove cartridge
filter "C".

- Make sure the pre-filter and drain cap O-rings are
in good condition.

- Lubricate them and refit the mesh filter and oil
drain cap by tightening to the prescribed torque.

- Refit a new cartridge filter making sure to lubri­cate the O-ring before fitting, then screw until it
comes into contact with the seal and further tighten
to the prescribed torque.

- Refit the muffler.

- Add recommended engine oil.

- Start the engine and let it run for a few minutes and then turn it off.
After 5 minutes check the level and top up, if necessary, never exceed the MAX. level.

N.B.

IF THE OIL IS CHANGED WITHOUT CHANGING THE CARTRIDGE FILTER (1ST COUPON) ADD
AROUND 1500 CC OF OIL INSTEAD OF 1700 CC SINCE PART OF THE LUBRICATION CIRCUIT
IS FILLED.

Characteristic

Engine oil:

1700 cm³

Locking torques (N*m)

Engine oil drainage plug 24 ÷ 30 Engine oil filter 12 - 16

MAIN - 9

Maintenance Nexus 500 euro 3

Oil pressure warning light

Warning light (low oil pressure)

The vehicle is equipped with a warning light on the
instrument panel that lights up when the key is
turned to the "ON" position. However, this light
should switch off once the engine has been star­ted.

If the light comes on during braking, at idling
speed or while turning, it is necessary to first
switch off the engine and then to check the oil
level and the lubrication system

Checking the valve clearance

- To check the clearance in the valves collimate
the references between the cam shaft control pul­ley and head.

- Use a feeler to make sure the clearance between
the valve and register screw correspond to the in­dicated values. If the clearance does not corre­spond, adjust it by loosening the counternut using
a screwdriver on the register screw as shown in
the figure.

Characteristic

Valve clearance: intake:

0.15 mm (when cold)

Valve clearance: exhaust

0.15 mm (when cold)

Cooling system

If noise or loss of liquid at the drain bore of the water pump is discovered, it will be necessary to overhaul
the pump as described in chapter "Flywheel cover".
Proceed to carry out a few preliminary operations as described below:

- Place the scooter on its centre stand and on flat ground.

- Remove the right footrest as described in the «Bodywork» Chapter.

- Remove the muffler to access the flywheel cover, as described in the «Engine» Chapter.

- Empty the cooling system by removing the couplings on the pump cover and the filler plug on the
expansion tank.

MAIN - 10

Nexus 500 euro 3 Maintenance

CAUTION

THIS OPERATION MUST BE CARRIED OUT WHEN THE ENGINE IS COLD.

- Remove the water pump cover as indicated in the
figure by loosening the 6 retaining screws.

- Proceeding as described in chapter "Engine",
partially drain the system and overhaul the pump.

- Refill and drain the system again once after hav­ing repaired the damaged and reinstalled all the
components.

N.B.

FOR CHANGING THE COOLANT AND BLEED­ING THE SYSTEM, SEE CHAPTER "COOLING
SYSTEM".

Characteristic

Cooling system

approx. 1.8 litres

Level check

The coolant level must checked every 6,000 kilo­metres with a cold engine, in the way shown be­low:

- Place the scooter on its centre stand and on flat
ground.

- Remove the cap of the expansion tank.

- To check the level, it is necessary to look inside
the expansion tank:
The reference mark in the figure shows the correct
coolant level.

-The coolant consists of an ethylene glycol and corrosion inhibitor based 50% demineralised water­antifreeze solution mix.

CAUTION

DO NOT EXCEED THE MAX. LEVEL WHEN FILLING SO AS TO AVOID THE COOLANT ESCAPING
FROM THE EXPANSION TANK WHEN THE vehicle IS IN USE.

N.B.

THE COOLANT CONSISTS OF A MIXTURE OF DE-IONISED WATER AND FLUID FOR SEALED
CIRCUITS. THE MIXTURE THUS OBTAINED LOWERS THE FREEZING POINT OF THE COOLANT
TO - 40°C. THE MIXTURE IN COMBINATION WITH THE PRESSURE OF 0.9 BAR RAISES THE
BOILING POINT TO APPROX. 125°C. THE RECOMMENDED LIQUID ALSO PROVIDES PROTEC­TIVE FUNCTIONS FOR THE ALUMINIUM ALLOYS. THIS CHARACTERISTIC MAY DECREASE
OVER THE COURSE OF TIME; THIS IS WHY A PERIODIC REPLACEMENT OF THE COOLANT IS
INDISPENSABLE.

N.B.

MAIN - 11

Maintenance Nexus 500 euro 3

FOR THE REPLACEMENT OF THE COOLANT AND THE FLUSHING OF THE SYSTEM, SEE
CHAPTER COOLING SYSTEM.

Braking system

Level check

- Position the vehicle on a flat surface and on the
centre stand.

- Check the brake fluid level via the special indi­cator located on the pump.

N.B.

THE LEVEL TENDS TO DROP AS THE BRAKE PADS GET WORN, A MINIMUM LEVEL SHOULD
NOT BE REACHED. IF THE LEVEL IS TOO LOW, CHECK AND FIX THE SYSTEM SEALS, IF RE­QUIRED. TOP UP THE PUMP TANK, IF REQUIRED, CONSIDERING THAT THE "MAX." LEVEL
MUST ONLY BE OBTAINED WITH NEW PADS.

Top-up

CAUTION

ONLY USE DOT 4-CLASSIFIED BRAKE FLUID.

Proceed as follows:

- Position the scooter on a flat surface and on the
centre stand.

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

CAUTION

MAIN - 12

Nexus 500 euro 3 Maintenance

MAKE SURE THE BRAKE FLUID DOES NOT GET INTO YOUR EYES OR ON YOUR SKIN OR
CLOTHES. IF THIS HAPPENS ACCIDENTALLY, WASH WITH WATER.

WARNING

BRAKE CIRCUIT FLUID IS VERY CORROSIVE; MAKE SURE THAT IT DOES NOT COME INTO
CONTACT WITH THE PAINTWORK

WARNING

THE BRAKE FLUID IS HYGROSCOPIC, IN OTHER WORDS, IT ABSORBS MOISTURE FROM THE
SURROUNDING AIR. IF THE HUMIDITY IN THE BRAKING FLUID EXCEEDS A CERTAIN VALUE,
IT WILL LEAD TO INEFFICIENT BRAKING; FOR THIS REASON, NEVER USE BRAKING FLUID
FROM CONTAINERS THAT HAVE ALREADY BEEN OPENED, OR PARTIALLY USED.

Characteristic

Prescribed fluid:

TUTELA TOP 4
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.

Headlight adjustment

- Place the scooter in use conditions, with tyres inflated to the prescribed pressure on flat ground at 10
m from a white screen placed in dim light.

- Make sure that the scooter's axle is perpendicular to the screen.

- Turn the headlight on and check that the limit of the light beam projected onto the screen does not
exceed 9/10 of the headlight centre height from the ground and that it is not less than 7/10.

MAIN - 13

Maintenance Nexus 500 euro 3

- Otherwise, adjust the right headlight by the screw
shown in the figure, which can be accessed by re­moving the front shield connecting member.

N.B.

THE ABOVE PROCEDURE COMPLIES WITH
THE EUROPEAN STANDARDS REGARDING
MAXIMUM AND MINIMUM HEIGHT OF LIGHT
BEAMS. REFER TO THE STATUTORY REGU­LATIONS IN FORCE IN EVERY COUNTRY
WHERE THE vehicle IS USED.

Checking the end compression pressure

- Remove the spark plug cap with the engine cold.

- Remove the spark plug.

- Fit a compression test gauge into the spark plug seat using a 10 mm spark plug union at the proper
tightening torque.

- Turn the switch to "ON", wait a few seconds and the disconnect the connector of the revolution sensor
to prevent the function of the injector and the spark plug.

- Allow the engine to run using the starter and with the throttle body in fully open position as long as the
gauge value is steady.

- If the pressure is higher than specified, remove the tool and reassemble the scooter.

- If the pressure is less than indicated, check the rpm at which the test is carried out; if it is less than
450 rpm, check the starter system.
If the final compression pressure is less than specified, remove the pressure gauge connector and inject
a few cc of oil into the combustion chamber, then turn the engine over (preferably by hand) to lubricate
the cylinder.
Repeat the compression test:
If the new value is also too low, check the valve seating.
Higher compressions on a new engine indicate poor seating of the segments.

Characteristic

Compression ratio

10.5: 1

Locking torques (N*m)

Spark plug 12 ÷ 14

MAIN - 14

INDEX OF TOPICS

ELECTRICAL SYSTEM ELE SYS

Electrical system Nexus 500 euro 3

KEY:

1. Magneto flywheel

2. Voltage regulator

3. Engine rev sensor

4. Throttle valve position sensor

5. Ambient temperature sensor

6. Stepping motor for idle nozzle

7. Electric fan

8. Engine temperature sensor

9. Remote control for electric fan

10. Overturn sensor

11. Injection load remote control

12. Key switch

13. Fuse box A

14. Main fuse

15. Fuse box B

16. Horn button

17. Horn

18. Engine stop remote control

19. Diode

ELE SYS - 2

Nexus 500 euro 3 Electrical system

20. Battery

21. Starter motor

22. Start-up remote control switch

23. Starter push button

24. Starter enable remote control

25. Engine stop switch

26. Centre stand switch

27. Rear brake stop button

28. Front brake stop button

29. Saddle opener actuator

30. Saddle opener receiver

31. 12V 180W socket

32. Helmet compartment light switch

33. Helmet compartment light

34. Preparation for anti-theft device

35. Left rear turn indicator bulb

36. Twin filament bulb tail light / stop light

37. Licence plate bulb

38. Right rear turn indicator bulb

39. Left front turn indicator bulb

40. Front right light assembly
A. Low beam light
B. Tail light

41. Front left light assembly
B. Tail light
C. High beam light

42. Right front turn indicator bulb

43. Headlight remote control

44. High beam passing mode switch

45. Light switch

46. Turn indicator assembly

47. Handlebar warning lights
A. Emergency lights
B. Tail lights
C. High beam light

48. Turn indicator switch

49. Electric control system

50. Mode button

ELE SYS - 3

Electrical system Nexus 500 euro 3

51. Emergency light switch

52. Oil pressure sensor

53. Instrument panel
A. Rpm indicator
B. Instrument panel bulbs

54. Instrument panel
A. Instrument panel bulbs
B. Immobilizer LED
C. Speedometer
D. Digital display
E. Engine Warning indicator light
F. Low fuel warning light
G. Oil warning light

55. Immobilizer aerial

56. Fuel pump / fuel level transmitter

57. Immobilizer decoder

58. Fuel injector

59. Spark plug

60. Tone wheel

61. HV coil

62. Lambda probe

63. Diagnostic socket

64. Fuel injection electronic control unit
Ar = Orange, Az = Sky Blue, Bi = White, Bl = Blue, Gi = Yellow, Gr = Grey, Ma = Brown, Ne = Black,

Ro = Pink, Rs = Red, Ve = Green, Vi = Purple

Components arrangement

Diagnostic socket

In order to access the diagnostic socket, remove the supports of the passenger footrest.

Overturn sensor

In order to access the overturn sensor, remove the
central union.

ELE SYS - 4

Nexus 500 euro 3 Electrical system

During assembly, observe the installation direction
shown in the figure.

H.V. coil

In order to access the high-voltage coil, remove
the left-hand side fairing.

Saddle opening ECU remote control.

Resetting of the remote control

Electronic control unit ECU

In order to access the immobilizer control unit, re­move the upper shield back plate.

ELE SYS - 5

Electrical system Nexus 500 euro 3

In order to access the connector, remove the wind­shield with the respective support and the metal
plate holding the control unit ECU, decoder and
saddle opener remote control.

N.B.

AFTER INSERTING THE INTERFACE CABLE
OR THE ELECTRONIC CONTROL UNIT, RE­TIGHTEN THE SCREW AND THE GROUND CA­BLE.

Immobiliser decoder

In order to access the immobilizer decoder, re­move the upper shield back plate.

Relays and diode group

In order to access the relays and the diode group,
remove the upper shield back plate.

Voltage regulator

In order to access the voltage regulator, remove
the lower cover.

ELE SYS - 6

Nexus 500 euro 3 Electrical system

Lambda probe

The lambda probe is mounted on the exhaust
manifold

Conceptual diagrams

Ignition

KEY:

3. Engine rpm sensor

11. Injection load remote control

12. Key switch

13. Fuse box A

14. Main fuse

15. Fuse box B

18. Engine stop remote control

ELE SYS - 7

Electrical system Nexus 500 euro 3

19. Diode

20. Battery

25. Engine stop switch

26. Centre stand switch

54. Instrument panel
A. Instrument panel bulbs
B. Immobilizer LED
C. Speedometer
D. Digital display
E. Engine Warning indicator light
F. Low fuel warning light
G. Oil warning light

55. Immobilizer aerial

57. Immobilizer decoder

59. Spark plug

61. HV coil

64. Fuel injection electronic control unit

Battery recharge and starting

KEY:

ELE SYS - 8

Nexus 500 euro 3 Electrical system

1. Magneto flywheel

2. Voltage regulator

12. Key switch

14. Main fuse

15. Fuse box B

18. Engine stop remote control

19. Diode

20. Battery

21. Starter motor

22. Start-up remote control switch

23. Starter push button

24. Starter enable remote control

25. Engine stop switch

26. Centre stand switch

27. Rear brake stop button

28. Front brake stop button

36. Twin filament bulb position light / stop light

Level indicators and enable signals section

KEY

ELE SYS - 9

Electrical system Nexus 500 euro 3

3. Engine rev sensor

4. Throttle valve position sensor

5. Ambient temperature sensor

6. Stepping motor for idle nozzle

8. Engine temperature sensor

11. Injection charge remote control

12. Key switch

13. Fuse box A

14. Main fuse

15. Fuse box B

18. Engine stop remote control

19. Diode

20. Battery

52. Oil pressure sensor

54. Instrument panel
A. Instrument panel light
B. Immobilizer LED
C. Speedometer
D. Digital display
E. Engine Warning indicator light
F. Low fuel warning light
G. Oil warning light

56. Fuel pump / fuel level transmitter

58. Fuel injector

60. Tone wheel

62. Lambda probe

64. Fuel injection electronic control unit

ELE SYS - 10

Nexus 500 euro 3 Electrical system

Devices and accessories

KEY

7. Electric fan

8. Engine temperature sensor

9. Remote control for electric fan

12. Key switch

13. Fuse box A

14. Main fuse

15. Fuse box B

16. Horn button

17. Horn

18. Engine stop remote control

19. Diode

20. Battery

25. Engine stop switch

26. Centre stand switch

29. Saddle opener actuator

30. Saddle opener receiver

31. 12V 180W socket

ELE SYS - 11

Electrical system Nexus 500 euro 3

32. Helmet compartment light switch

33. Helmet compartment bulb

64. Fuel injection electronic control unit

Lights and turn indicators

LEGENDA

12. Commutatore a chiave

13. Scatola portafusibili A

14. Fusibile principale

15. Scatola portafusibili B

20. Batteria

34. Predisposizione antifurto

35. Lampada indicatore di direzione posteriore Sx

36. Lampada doppio filamento Luce di posizione/Luce stop

37. Lampada luce targa

38. Lampada indicatore di direzione posteriore Dx

39. Lampada indicatore di direzione anteriore Sx

40. Gruppo ottico anteriore Dx
A. Lampada anabbagliante
B. Luce di posizione

ELE SYS - 12

Nexus 500 euro 3 Electrical system

41. Gruppo ottico anteriore Sx
B. Luce di posizione
C. Lampada abbagliante

42. Lampada indicatore di direzione anteriore Dx

43. Teleruttore proiettore

44. Pulsante abbagliante modalità Pass

45. Deviatore luci

46. Dispositivo lampeggiatori

47. Spie gruppo manubrio
A. Lampeggiatori di emergenza
B. Luci di posizione
C. Luce abbagliante

48. Commutatore indicatori di direzione

49. Dispositivo gestione comandi elettrici

51. Interruttore lampeggiatori di emergenza

53. Quadro strumenti
A. Contagiri
B. Lampade illuminazione strumento

54. Quadro strumenti
A. Lampade illuminazione strumento
B. Led immobilizer
C. Tachimetro
D. Display digitale
E. Spia Warning motore
F. Spia Riservacarburante
G. Spia olio
H.

Checks and inspections

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.
This, in its turn, is connected directly to the ground and the battery positive terminal passing through
the 30A protective fuse.
This system therefore requires no connection to the key switch.

ELE SYS - 13

Electrical system Nexus 500 euro 3

The three- phase generator provides good recharge power and at low revs a good compromise is
achieved between generated power and idle stability.

Stator check

Stator winding check-up

WARNING

THE CHECK-UP CAN BE MADE WITH THE STATOR PROPERLY INSTALLED.

1) Remove the central chassis cover.

2) Disconnect the connectors between stator and regulator with the three yellow cables.

3) Measure the resistance between each of the yellow terminals and the other two.

Electric characteristic

Resistance:

0.2 - 1 Ω

4) Check that there is insulation between the each
yellow cable and the ground.

5) If values are incorrect, replace the stator.

Recharge system voltage check

VOLTAGE REGULATOR/RECTIFIER

Specification Desc./Quantity

Type Non-adjustable three-phase transistor

Voltage 14 ÷ 15V at 5000 rpm with lights off

Maximum current output check.

- With engine off and panel set to "ON" turn on the lights and let the battery voltage set to 12V.

- Connect ammeter pliers to the 2 recharge positive poles in output from the regulator.

- Keep the lights on and start the engine, bring it to normal speed and read the values on the ammeter.
With an efficient battery a value must be detected: > 20A

Check the charging current

WARNING

BEFORE CARRYING OUT THE CHECK, MAKE SURE THAT THE BATTERY IS IN GOOD WORK­ING ORDER.

1) Place the vehicle on its centre stand

ELE SYS - 14

Nexus 500 euro 3 Electrical system

2) With the battery correctly connected to the circuit, place the tester terminals between the battery
terminals..

3) Start the engine, ensure that the lights are all out, increase the engine speed and at the same time
measure the voltage.

Electric characteristic

Voltage ranging between 14.0 and 15.0V at 5000 rpm.

Look for any leakage

1) Check that the battery exhibits no liquid leaks before checking the output voltage.

2) Turn the ignition key to OFF and connect the tester terminals between the battery negative pole (-)
and the Black cable.

3) With the tester terminals connected, disconnect the Black cable from the battery negative (-) pole.

4) With ignition key still at OFF, the reading detected by the amperometer must be ≤ 0.5 mA.

Turn signals system check

The circuit of the turn indicators is controlled by the electrical control device and the instrument panel.
In the event of a malfunction, proceed as follows:

1. Check the function of the bulbs

2. Check the function of the turn signal indicator switch

3. Without disconnecting the instrument panel, with the key switch in position ON and with the engine

stop switch in position RUN, check for intermittent voltage between terminals 9-ground and 10-ground
of the large 20-pin connector.
If there is no voltage, check the wiring and the correct function of the electrical control units. If the fault
persists, replace the instrument panel.

Lights list

LIST OF BULBS

Specification Desc./Quantity

1 High-beam / low-beam headlights 2 12V-55W, halogen (H7)
2 Position light / front headlight 2 12V-5W, all-glass
3 Turn indicator bulb 4 12V-10W, spherical
4 Tail light bulb and light 1 12V-21/5W, spherical, twin-filament
5 Licence plate bulb 1 12V-5W, all-glass
6 Helmet compartment bulb 1 12V-5W, cylindrical

ELE SYS - 15

Electrical system Nexus 500 euro 3

Fuses

The electrical system is equipped with:

1. Six fuses "A" located on the shield back plate

2. Five fuses "B" located in the helmet compart-

ment

3. One fuse of 30A "D" (main fuse), located near
the battery on the left-hand side, under which is

also a replacement fuse.

The rating of the various fuses are stamped on the

fuse holders "C".

To replace the fuse, use the gripper provided in the

tool bag.

The table shows the position and characteristics

of the fuses installed in the scooter.

CAUTION

BEFORE REPLACING THE BLOWN FUSE,
FIND AND SOLVE THE FAILURE THAT
CAUSED IT TO BLOW. NEVER TRY TO RE­PLACE THE FUSE WITH ANY OTHER MATERI­AL (E.G., A PIECE OF ELECTRIC WIRE).

FUSIBILE PRINCIPALE

Specification Desc./Quantity

1 Generale Nominazione: Fuse 1

Soglia di intervento: 30A

Collocazione: Vano batteria

PORTAFUSIBILI «B»

Specification Desc./Quantity

1 Non utilizzato Nominazione: -

Soglia di intervento: -

Collocazione: Vano portacasco

2 License plate bulb - position lights - instru-

ment panel lights

3 Instrument panel power supply Designation:Fuse 3

ELE SYS - 16

Designation:Fuse 2

Threshold of operation: 3 A

Location: Helmet compartment

Threshold of operation: 7.5 A

Nexus 500 euro 3 Electrical system

Specification Desc./Quantity

Location: Helmet compartment

4 Seat opener receiver power supply - anti-

theft device preparation

5 Horn - emergency stop warning light - instru-

ment panel permanent power supply - light

controller

6 Helmet compartment light - socket

12V-180W - anti-theft device preparation

FUSE HOLDER "B"

Specification Desc./Quantity

1 Immobilizer decoder power supply - ignition

ECU power supply

2 Ignition ECU - immobilizer decoder (+ per-

manent power supply)

3 Stop light - starter remote control coil Designation:Fuse 9

4 High-beam lamp with warning light Designation:Fuse 10

5 Low beam lamp Designation:Fuse 11

6 HV coil - fuel injector - fuel pump - remote

control injection load

Designation:Fuse 4

Threshold of operation: 7.5 A

Location: Helmet compartment

Designation:Fuse 5

Threshold of operation: 7.5 A

Location: Helmet compartment

Designation:Fuse 6

Threshold of operation: 15 A

Location: Helmet compartment

Designation:Fuse 7

Threshold of operation: 3 A

Location: Shield back plate

Designation:Fuse 8

Threshold of operation: 5A

Location: Shield back plate

Threshold of operation: 7.5 A

Location: Shield back plate

Threshold of operation: 7.5 A

Location: Shield back plate

Threshold of operation: 7.5 A

Location: Shield back plate

Designation:Fuse 12

Threshold of operation: 10 A

Location: Shield back plate

ELE SYS - 17

Electrical system Nexus 500 euro 3

Remote control switches

The electrical system has 6 remote control
switches located under the front shield.
In order to access the remote control switches:

•

Remove the front shield.

•

- Remove the front knee guard.

The following table shows the functions of each
remote control switch:

Remote

control

switch

A Immobiliser remote control switch
B Electric fan remote control switch
C Light remote control switch
D Engine stop remote control switch
E Electronic control unit remote

F Starter remote control switch

Description

control switch

Dashboard

The digital display has two service symbols:

SERVICE (Service coupon):

The lamp should come on after reaching 1000 km
or 1 year after initial activation, then every 6000 km
or 1 year after the last activation.

BELT:

This lamp should come on every 12000 km.

ELE SYS - 18

Nexus 500 euro 3 Electrical system

•

Press buttons "MODE" and "ODO/SET" simultaneously at the moment you turn the key to
"ON" for more than 3 seconds: The "BELT" symbol starts to flash.

•

Pressing the button "MODE" for less than 1 second displays the symbols in turn. The se­lected symbol remains lit.

•

Pressing button "MODE" for longer than 3 seconds resets the kilometre reading for the
symbol selected, in "SERVICE" mode the date is also reset.

N.B.

•

AT THE MOMENT THE DATE IS RESET, THE "SERVICE" SYMBOL IS ACTIVATED
AGAIN.

•

PERFORM THE RESET PROCEDURE ONLY AT THE MOMENT OF DELIVERY OF THE
SCOOTER TO THE CUSTOMER IN ORDER THAT THIS SYMBOL SIGNALS THE NEED
FOR THE FIRST SERVICE IN RELATION TO THE DISTANCE TRAVELLED AND THE
TIME SINCE THE ACTIVATION.

The scooter has an instrument panel subdivided
into 3 sections: Digital instrument with LCD display
and analogue speedometer, analogue rpm indica­tor and warning light group.

• Warning light group
The warning light group includes:

- Emergency light warning light (red)

- Position light and low-beam warning light (green)

- High beam warning light (blue)

- Spare warning light

- The emergency control unit may be switched ON
and OFF only with the key in position "ON" and
must continue to function with the key in position
"OFF".

• Digital instrument
The digital section provides the displays of:

- Injection warning light (amber)

- Low fuel warning light (amber)

- Oil pressure warning light (red)

- Turn signal warning light (green)

- Immobilizer LED (red)

ELE SYS - 19

Electrical system Nexus 500 euro 3

The digital section of the instrument panel is com­pleted by a liquid crystal display and 3 control
buttons (MODE - CLOCK - ODO/SET).

- The LCD panel provides a 5-digit display for the visualisation of:

• Total kilometres

• Trip kilometres

• Clock

N.B.

IT IS POSSIBLE TO CHANGE THE DISPLAY TO KM OR MILES BY PRESSING THE BUTTONS
"MODE" AND "CLOCK" SIMULTANEOUSLY FOR LONGER THAN 3 SECONDS AT THE MOMENT
YOU TURN THE KEY TO POSITION "ON". THE WORD "SET" WILL BE DISPLAYED.

- Pushing the "MODE" button for less than a second displays the following function sequence:

1. Average speed
The word "MEAN" appears together with km/h or mph.
The value is calculated on the basis of the trip kilometre reading.

2. Maximum speed
The word "MAX" appears together with km/h or mph.
The value is calculated on the basis of the trip kilometre reading.

3. Average consumption
The fuel symbol, the word "MEAN" and km/h or mph appear.
The value is calculated on the basis of the trip kilometre reading.

4. Momentary consumption
The fuel symbol and km/h or mph appear.

5. Range
The fuel icon appears.
If the range drops below 40 km, the symbol appears automatically and flashes for 60 seconds.
When the low fuel warning light comes on permanently, dashes appear instead of the range value.

6. Battery voltage
The battery symbol appears
Pressing button "MODE" for longer than 3 seconds returns you to function "1" of the sequence (average
speed).

ELE SYS - 20

Nexus 500 euro 3 Electrical system

- The display also contains the symbols:

BELT:
Indicates the need to replace the transmission
belt

This lamp should come on and flash every 12000
km.

SERVICE (Service coupon):
Indicates the need to carry out the scheduled maintenance operations.

The lamp should come on after reaching 1000 km or 1 year after initial activation, then every 6000 km
or 1 year after the last activation.

WARNING

THE SCOOTER SHOULD BE SERVICED IN ANY CASE AT THE KILOMETRE INTERVALS INDI­CATED IN THE OPERATING AND MAINTENANCE MANUAL; DO NOT RELY ON THE SERVICE
DISPLAY THAT APPEARS ON THE INSTRUMENT PANEL.

Data check function

Setting the clock.

To set the clock, press the button "CLOCK" for more than 3 seconds.
The figures showing the hours start to flash.
Set the hours with the button "ODO/SET".
Press button "CLOCK" again and the figures showing the minutes start to flash.
Set the minutes with the «ODO/SET» button.
Press the «CLOCK» button again to start the clock moving normally.
During the reset process, not pressing any buttons for 8 seconds ends the process and the display will
automatically show the modified time.

Setting the date.

Set the "DATE" using the "CLOCK".
If the button "CLOCK" is pressed for longer than 3 seconds, the figures showing the days start to flash.
Set the day with the «ODO/SET» button.
Press the "CLOCK" button again; the numbers showing the months start to flash.

ELE SYS - 21

Electrical system Nexus 500 euro 3

Set the month with the "ODO/SET" button.
Press the "CLOCK" button again; the numbers showing the years start to flash.
Set the year with the "ODO/SET" button.
Press the «CLOCK» button again to start the clock moving normally.
During the reset process, not pressing any buttons for 8 seconds ends the process and the display will
automatically show the modified date.

Sealed battery

Sealed battery start-up operations

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 BATTERY REFRESH AFTER OPEN CIRCUIT STORAGE

1) Voltage check

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).

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 nominal capacity of the battery

- Charge time: 5 h

Specific tooling

020333Y Single battery charger
020334Y Multiple battery charger

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

CAUTION

ELE SYS - 22

Nexus 500 euro 3 Electrical system

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

CHARGE THE BATTERY BEFORE USE TO ENSURE OPTIMUM PERFORMANCE. FAILURE TO
CHARGE THE BATTERY ADEQUATELY BEFORE BEING PUT INTO OPERATION WILL LEAD TO
A PREMATURE FAILURE OF THE BATTERY.

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.

Dry-charge battery

- 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 Bé at a minimum tem­perature of 15°C until the upper level is reached.

- Allow to stand for at least 2 hours, then top up the
level with sulphuric acid.

- Within 24 hours, recharge using the special bat­tery charger (single) or (multiple) at an intensity of
about 1/10 of the battery nominal capacity and until
the acid gravity is about 1.27, corresponding to 31
Bé and such values become steady.

- After charging, top up the acid (adding distilled
water). Close and clean carefully.

- After carrying out the operations above, install the
battery on the scooter, observing the connections
described in point 3) of paragraph "Battery re-

charge".

Specific tooling

020333Y Single battery charger
020334Y Multiple battery charger

1 Keep the pipe in vertical position
2 Inspect visually
3 The float must be freed

Checking the electrolyte level

ELE SYS - 23

Electrical system Nexus 500 euro 3

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's electrical
system: the battery works overcharged and is subject to quick wear.

Charging status check

After topping-up the electrolyte level, check its density using special density gauge.
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. When refitting the battery onto the
scooter pay attention not to invert the cables, bearing in mind that the earth (black) wire marked with
a (-) must be connected to the negative terminal whilst the other two red wires, marked with a (+) must
be attached to the positive, + terminal.

Battery recharge

WARNING

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

Remove the battery from the vehicle removing the negative clamp first.
Normal bench charging must be performed using the special battery charger (single) or (multiple), set­ting the battery charge selector to the type of battery that requires recharging (i.e., at a current equal
to 1/10 of the battery rated capacity). Connections to the power supply source must be implemented
by connecting corresponding poles (+ to + and - to - ).

Specific tooling

020333Y Single battery charger
020334Y Multiple battery charger

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

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

CHARGE THE BATTERY BEFORE USE TO ENSURE OPTIMUM PERFORMANCE. FAILURE TO
CHARGE THE BATTERY ADEQUATELY BEFORE BEING PUT INTO OPERATION WILL LEAD TO
A PREMATURE FAILURE OF THE BATTERY.

ELE SYS - 24

Nexus 500 euro 3 Electrical system

Phonic wheel

- Ensure that the tone wheel is correctly installed on the scooter and connected to the electrical system.

- Turn the key switch to "ON".

- Access the tone wheel connector on the system side.

- Carry out the following measurements using the special tool.

Specific tooling

020331Y Digital multimeter

Check the supply voltage.

Keeping the connector in the position shown in the
photo, check for battery voltage (12 V) with the
polarity shown.
If incorrect values are measured, check the elec­trical system and the digital instrument.

N.B.

A DROP IN VOLTAGE OF 1 V IN RELATION TO
THE BATTERY VOLTAGE CAN BE CONSID­ERED NORMAL.

Check the signal

Move the positive rod to the position shown in the
photo. Turn the front wheel very slowly and check
that the measured voltage is 0 V or battery voltage,
depending on the position taken up.
This condition should be repeated 16 times during
a complete revolution of the wheel.

N.B.

THE DIGITAL MULTIMETER IS NOT ABLE TO
DISPLAY THE VOLTAGE WHEN THE WHEEL
IS ROTATED FAST.

If other voltages are measured or there is no alternation, replace the tone wheel.

Connectors

ELE SYS - 25

Electrical system Nexus 500 euro 3

ECU

Layout of the system-side connectors and the con­nectors on the electronic control unit.

ECU

Specification Desc./Quantity

1 Throttle potentiometer power supply +5 V
2 Oxygen sensor (-)
3 Rpm indicator / consumption counter
4 Engine temperature (+)
5 86 electric fan remote control switch
6 Stepper motor Stepper motor
7 Engine rpm sensor
8 Oxygen sensor (+)
9 EMS diagnostic connector
10 EMS diagnostic connector
11 Throttle potentiometer signal
12 Engine rpm sensor
13 Injector control (negative)
14 Stepper motor Stepper motor
15 Injection warning light (-)
16 Decoder (serial) Overturn sensor
17 Battery power supply (+)
18 Air temperature sensor (+)
19 Fuel pump (-)
20 H.V. coil (negative control)
21 Stepper motor Stepper motor
22 Sensor power supply (-)
23 Control unit negative
24 Stepper motor Stepper motor
25 Turn indicator control device
26 Continuous power supply (positive)

ELE SYS - 26

Nexus 500 euro 3 Electrical system

Seat opening receiver

RECEIVER CONTROL UNIT FOR SADDLE OPENER

Specification Desc./Quantity

1 Radio aerial
2 Actuator positive output 1
3 Reset / Input cancel
4 Battery positive
5 (Not connected)
6 Live positive
7 Earth
8 (Not connected)
9 (Not connected)
10 Selection input CH1 / CH3
11 Positive output actuator 1
12 Data for alarm output

Immobiliser decoder

IMMOBILIZER DECODER

Specification Desc./Quantity

1 ­2 Immobilizer LED control (negative)
3 Base power supply (positive)
4 Negative
5 ­6 Electronic control unit EMS (serial)
7 ­8 Continuous power supply (positive) Immobilizer aerial

ELE SYS - 27

Electrical system Nexus 500 euro 3

Engine rev. sensor

REV SENSOR

Specification Desc./Quantity

1 M: Male
2 F: Female
3 S: Shielding

Dashboard

The instrument panel is provided with two connec­tors ("A" with 20 pins and "B" with 12 pins) shown
in the figure.

Connector "A"
KEY:

1. Wheel sensor (+)

2. Wheel sensor signal

3. Wheel sensor (-)

4. Lights

5. Engine rpm signal

6.Water temperature

7.Water temperature (-)

8. Oil pressure

9. Right turn indicator

ELE SYS - 28

Nexus 500 euro 3 Electrical system

10. Left turn indicator

11. Fixed battery

12. Immobilizer LED

13. Permanent power supply (+)

14. Turn indicator assembly

15. Pump level sensor

16. -

17. Injection LED

18. Right turn indicator warning light

19. Left turn indicator warning light

20. Emergency warning flashers

Connector "B"
KEY:

1. Rpm indicator (D)

2. Rpm indicator (B)

3. -

4. -

5. ICP/ID "NEXUS 500"

6. ICP/ID "NEXUS 250"

7. Rpm indicator (C)

8. Rpm indicator (A)

9. -

10. -

11. -

12. ICP/ID "COMAND ID"

Analogue odometer

ANALOGUE RPM INDICATOR

Specification Desc./Quantity

1 STEPPER MOTOR A
2 STEPPER MOTOR B
3 STEPPER MOTOR C
4 STEPPER MOTOR D

Remote seat opening

The vehicle is equipped with a remote control to open the saddle.

ELE SYS - 29

Electrical system Nexus 500 euro 3

This remote control is supplied together with the keys and at the manufacturing stage, it has been
programmed to work together with the ECU that control the opening device.
If the remote control is lost, a new one can be requested and programmed, by resetting the ECU memory
and following the same steps as per programming the immobilizer system in the keys.

Battery replacement

The remote control for the black key is powered by
inner batteries that get discharged after extended
use.
You may need to replace the batteries if the re­mote control fails or if its range of operation is
reduced.
To perform such operation remove the three
screws and open the two half shells.

Electric characteristic

Batteries used:

CR1616

Zeroing

- Remove the front shield to gain access to the re­ceiver control unit / seat opener controller.

- Within the electrical wiring harness there are two
cables, one black (ground) and one black/blue
coming from pin 3 of the control unit.

- Connect the two cables for at least 10 seconds
to cancel all the remote control commands stored
in the control unit.

Programming

- Follow these steps to program the remote controls:

1. Insert the remote control key to be programmed in the steering lock key block.

ELE SYS - 30

Nexus 500 euro 3 Electrical system

2. Turn the key to ON, press the button of the remote control, release the button, turn the key from ON
back to OFF, all within four seconds.

3. Wait for 1 to 8 seconds.

4. Repeat steps 2 and 3 for 4 times without removing the key. The control unit confirms the programming
has been successfully executed by opening the saddle.

N.B.

THE CONTROL UNIT CAN PROGRAMME UP TO 7 REMOTE CONTROLS.

ELE SYS - 31

Electrical system Nexus 500 euro 3

ELE SYS - 32

INDEX OF TOPICS

ENGINE FROM VEHICLE ENG VE

Engine from vehicle Nexus 500 euro 3

Exhaust assy. Removal

- Loosen the two mountings of the exhaust mani­fold at the cylinder head.

- Remove the Lambda probe from its support and
disconnect it.

Remove the screw indicated in the photograph.

- Loosen the screw shown in the figure so as to
loosen the muffler strap and remove the whole
muffler.

ENG VE - 2

Nexus 500 euro 3 Engine from vehicle

N.B.

DUE TO MUFFLER DIMENSIONS IT IS NOT
POSSIBLE TO ACTUATE ON THE SCREW
PERPENDICULARLY TO REMOVE IT; USE A
COMMERCIALLY AVAILABLE "BONDUS"
MALE HEXAGONAL WRENCH.

Remove the lambda probe from the manifold.

Removal of the engine from the vehicle

Fitting the engine on the vehicle

- Perform the operations for removal but in reverse order according to the locking torque indicated in
«Specifications» Chapter.

CAUTION

PAY PARTICULAR ATTENTION TO POSITIONING THE THROTTLE COMMAND TRANSMISSION
PROPERLY.

Check that with valve in abutment against the register there is a small clearance.

-Check the engine oil level and if necessary top it up with the recommended type.

- Top up the cooling circuit.

- Check the functioning of the accelerator and the electrical devices.

Removal of engine

WARNING

CARRY OUT THESE OPERATIONS WHEN THE ENGINE IS COLD.

- Disconnect the battery

- Remove the underseat compartment.

- Drain the coolant.

- Remove the complete muffler assembly.

- Remove the rear wheel.

- Remove the swinging arm.

- Remove the throttle control transmission.

ENG VE - 3

Engine from vehicle Nexus 500 euro 3

- Remove the air filter coupling and the collector.

- Disconnect the ground cable from the engine.

- Disconnect the carburettor electrical devices and the starter motor power supply cable.

- Disconnect the fuel delivery and return pipes from the carburettor and the cooling system piping (outlet
from the head and inlet to the thermostat).

- Disconnect the HV cable from the spark plug.

- Disconnect the alternator cable from the electrical system of the scooter.

WARNING

BE VERY CAREFUL WHEN HANDLING FUEL.

CAUTION

WHEN INSTALLING THE BATTERY, ATTACH THE POSITIVE LEAD FIRST AND THEN THE NEG­ATIVE LEAD.

ENG VE - 4

INDEX OF TOPICS

ENGINE ENG

Engine Nexus 500 euro 3

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

Automatic transmission

Transmission cover

- Using a screwdriver, remove the driven pulley
axle cover near the bottom of the cap.

- Loosen the driven pulley shaft fastening nut using
a misaligned wrench and prevent the pulley shaft
rotation using a machine hexagon bush.

- Remove the nut and the two washers.

N.B.

DUE TO THE HIGH TIGHTENING TORQUE, US­ING DIFFERENT WRENCHES - SUCH AS A
CONVENTIONAL POLYGONAL BUSH - MAY
DAMAGE THE HEXAGON OBTAINED ON THE
SHAFT OR BREAK THE BUSH ITSELF.

- Remove the six M6 screws.

ENG - 2

Nexus 500 euro 3 Engine

- Remove the four M8 screws.

- Remove the transmission cover.

- Check that the bearing rotates freely, otherwise
replace it.

- Loosen the 4 fastening screws

- Extract the outside plastic transmission cover.

Air duct

- Remove the transmission cover.

- Unscrew the two screws shown in the figure to
remove the air conveyor.

Locking torques (N*m)

Air conveyor screws 11 ÷ 12

- Remove the external transmission cover.

- Unscrew the 4 fastening screws shown in the fig­ure to remove the external air conveyor.

ENG - 3

Engine Nexus 500 euro 3

Air duct filter

- Remove the external air conveyor.

- Unscrew the 2 fastening screws shown in the fig­ure to remove the conveyor filter.

Removing the driven pulley shaft bearing

- Remove the transmission cover.

- Remove the seeger ring.

- Place transmission cover on a wood surface and
use the special tool so that it is adequately sup­ported.

- Pull out the bearing using the special tool.

N.B.

BELL MUST BE PLACED INTO THE TRANS­MISSION COVER, CLOSE TO THE BEARING
SEAT AND THE WOODEN SURFACE, SINCE
WITHOUT BELL THE ENTIRE COVER STRUC­TURE WOULD BEND. NOT ONLY IN THE AREA
OF MAXIMUM STURDINESS.

Specific tooling

001467Y002 Driver for OD 73 mm bearing
020376Y Adaptor handle
020375Y Adaptor 28 x 30 mm
020439Y 17 mm guide

ENG - 4

Nexus 500 euro 3 Engine

Refitting the driven pulley shaft bearing

- Heat the transmission cover interior using the
heat gun.

N.B.

BE CAREFUL NOT TO OVERHEAT THE COV­ER AS THIS WOULD DAMAGE THE OUTSIDE
PAINTED SURFACE.

Specific tooling

020151Y Air heater

- Place the bearing onto the special tool with a little
grease to prevent it from coming out.

- Install the new bearing using the special tool.

N.B.

PROPERLY SUPPORT THE OUTSIDE COVER
TO PREVENT DAMAGING THE PAINTED SUR­FACE.

Specific tooling

020376Y Adaptor handle
020358Y 37x40-mm adaptor
020439Y 17 mm guide

Baffle roller

Plastic roller

Installation of belt anti-vibration roller

- Install the anti-flapping roller with the lip facing
the engine crankcase.

- Tighten the central screw to the prescribed tor­que.

N.B.

TURN THE DRIVEN AND/OR DRIVING PULLEY
UNTIL A CORRECT TENSIONING OF THE
BELT IS OBTAINED.

Locking torques (N*m)

Anti-vibration roller screw 16.7 - 19.6

ENG - 5

Engine Nexus 500 euro 3

- Check that the roller does not show signs of wear
and that it turns freely.

- Loosen the retaining bolt using a 13 mm spanner.

- Remove the complete roller with bearing.

N.B.

IF THE ROLLER DOES NOT ROTATE FREELY,
REPLACE THE COMPLETE ROLLER.

Removing the driven pulley

- Remove the driven pulley assembly with the belt.

Inspecting the clutch drum

- Remove the clutch bell.

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

- Measure the clutch bell inside diameter.

N.B.

CHECK THE ECCENTRICITY MEASURED, 0.2
MM MAX.

Characteristic

Max. value:

160.5 mm

Standard value:

ENG - 6

Nexus 500 euro 3 Engine

160.2 mm

Removing the clutch

- To remove the clutch with the driven pulley it is
necessary to use the special tool;

- Arrange the tool with the mean pins screwed in
position "E" on the inside;

- Install the driven pulley unit onto the tool inserting
the pins into the ventilation holes;

- Move the rear stop screw in abutment against the
fixed driven pulley as shown in the figure.

CAUTION

THE TOOL SHOULD BE FIRMLY SECURED IN A VICE USING THE SPECIAL TOOL. DO NOT
TIGHTEN THE REAR SCREW TOO MUCH AS THIS COULD CAUSE AN IRREVERSIBLE TOOL
DEFORMATION.
USING THE SPECIAL 55-MM WRENCH, REMOVE THE FASTENING RING NUT.
LOOSEN THE TOOL SCREW AND DISASSEMBLE THE DRIVEN PULLEY UNIT, CLUTCH, SPRING
WITH SHEATH.

Specific tooling

020444Y Tool for fitting/ removing the driven pulley clutch

Pin retaining collar

- Extract the collar using 2 screwdrivers.

- Remove the 4 guide pins.

- Extract the moving driven half-pulley.

ENG - 7

Engine Nexus 500 euro 3

Removing the driven half-pulley bearing

- Check that the bushing is free from wear and
damage; otherwise replace the fixed driven half­pulley.

- Remove the lock ring using pliers.

- Using the special tool inserted through the roller
bearing, pull out the ball bearing.

N.B.

PROPERLY SUPPORT THE PULLEY TO PRE­VENT DAMAGING THE THREADING.

Specific tooling

020376Y Adaptor handle
020456Y Ø 24 mm adaptor
020363Y 20 mm guide

N.B.

IF YOU NEED TO OVERHAUL THE BEARINGS ON AN ASSEMBLED DRIVEN PULLEY UNIT, IT IS
NECESSARY TO SUPPORT THE UNIT BY THE BELL

Specific tooling

001467Y002 Driver for OD 73 mm bearing

- Remove the roller bearing using the special tool,
supporting the fixed half-pulley with the bell.

Specific tooling

020376Y Adaptor handle
020375Y Adaptor 28 x 30 mm
020364Y 25-mm guide
001467Y002 Driver for OD 73 mm bearing

ENG - 8

Nexus 500 euro 3 Engine

Inspecting the driven fixed half-pulley

- Check that the belt contact surface is free from
wear.

- Measure the outer diameter of the pulley bushing.

Characteristic

Minimum admissible diameter

49.96 mm

Standard diameter:

49.965 mm

Inspecting the driven sliding half-pulley

- Check that the belt contact surface is free from
wear.

- Remove the 2 inside sealing rings and the 2 out­side O-rings.

- Measure the movable half-pulley bushing inside
diameter.

Characteristic

Maximum admissible diameter:

50.08 mm

Standard diameter:

50.085 mm

Refitting the driven half-pulley bearing

- Install a new roller bearing using the special tool.

N.B.

PLACE THE BEARING WITH THE WRITINGS AND THE EMBEDDED OIL GUARD FACING OUT­WARDS.

- Properly support the half-pulley to prevent damaging the threading.
If you are working on the driven pulley unit fully assembled, use the special tool.

ENG - 9

Engine Nexus 500 euro 3

Specific tooling

020478Y Punch for driven pulley roller casing
001467Y002 Driver for OD 73 mm bearing

- Install a new ball bearing using the special tool.

Specific tooling

020376Y Adaptor handle
020477Y Adaptor 37 mm
020363Y 20 mm guide

- Insert the seeger lock ring.

Refitting the driven pulley

- Insert the new oil guards

- Insert the new O-rings

N.B.

O-RINGS ARE OF TWO SIZES. THE LARGE ONE IS INSTALLED ON THE MACHINING END RA­DIUS, AT THE BASE OF THE HALF-PULLEY.

- Install the half-pulley on the bushing being careful
not to damage the top sealing ring during the in­troduction.

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

- Using a bent beak greaser, lubricate the driven pulley unit with about 10 gr. of grease, this operation
should be carried out through one of the two holes into the bushing to obtain the exit of the grease from
the opposite hole. This operation is necessary to avoid the presence of grease beyond the O-rings.

Recommended products

AGIP GREASE SM 2 Grease for the tone wheel revolving ring

ENG - 10

Nexus 500 euro 3 Engine

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

Inspecting the clutch spring

- Measure the length of the spring, while it is re­laxed.

Characteristic

Standard length:

125.5 mm

Admissible limit after use:

120 mm

- Check the thickness of the clutch mass friction material.

Characteristic

Minimum thickness permitted:

1 mm

- The masses must exhibit no traces of lubricants;
in that case, check the driven pulley unit seals.

N.B.

UPON RUNNING-IN, THE MASSES MUST EXHIBIT A CENTRAL CONTACT SURFACE AND MUST
NOT BE DIFFERENT FROM ONE ANOTHER. VARIOUS CONDITIONS CAN CAUSE THE CLUTCH
TO TEAR.

- Do not open the masses using tools to prevent a variation in the return spring load.

ENG - 11

Engine Nexus 500 euro 3

Refitting the clutch

Bell assembly

- Install the bell and the spacer.

- Prepare the special tool as for removal;

- Preassemble the driven pulley unit with the drive
belt according to its direction of rotation;

- Insert the driven pulley unit, the spring with
sheath and clutch into the tool.

Specific tooling

020444Y Tool for fitting/ removing the driven
pulley clutch

- Compress the spring and insert the clutch on the driven pulley bushing.

N.B.

BE CAREFUL NOT TO DAMAGE THE SHEATH OR THE BUSHING THREADED END.

- Tighten the ring nut by hand and complete the
tightening using the special wrench to the prescri­bed torque.

Specific tooling

020444Y Tool for fitting/ removing the driven
pulley clutch

Locking torques (N*m)

Clutch ring nut 65 - 75

- To facilitate reassembly on the engine, turn the moving driven pulley and insert the belt onto the smaller
diameter.

ENG - 12

Nexus 500 euro 3 Engine

Refitting the driven pulley

- Install the driven pulley assembly with belt.

Drive-belt

- Check that the driving belt is not damaged.

- Check the width of the belt.

Characteristic

Minimum width:

25 mm

Standard width:

26.2 mm

Removing the driving pulley

- Using a 27 mm wrench, turn the central pulley nut
to horizontally align the central inside holes and
install the special tool.

Specific tooling

020474Y Driving pulley lock wrench

ENG - 13

Engine Nexus 500 euro 3

- First install the lock ring of the special tool onto
the pulley so that the splines are completely en­gaged.

- Then, insert the tool so as to insert the stud bolts
on the ring into the holes obtained onto the tool
itself.

- Tighten the two tool fastening nuts, also by hand.

- Loosen the central nut.

- Remove the spring washer and the flat washer.

- Remove the fixed driving half-pulley.

- Remove the bushing connection washer.

- Move the belt downwards.

- Suitable support the roller contrast and extract
the mobile driving half-pulley with the relevant
bushing and the rear washer, being careful not to
make the rollers come out.

Inspecting the rollers case

- Check that the inside bushings shown in the figure are not worn and measure the inside diameter.

CAUTION

DO NOT LUBRICATE OR CLEAN THE BUSHINGS

Characteristic

Maximum admissible diameter:

30.12 mm

Standard diameter:

30.021 mm

- Measure the pulley sliding bushing outside di­ameter shown in the figure.

Characteristic

ENG - 14

Nexus 500 euro 3 Engine

Minimum admissible diameter

Ø 29.95 mm

Standard diameter:

Ø 29.959 mm

- Check that the rollers are not damaged or worn.

Characteristic

Minimum admissible diameter

Ø 24.5 mm

Standard diameter:

Ø 24.9 mm

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

- Check the wear of the roller housings and of the
belt contact surfaces on both pulley halves.

Refitting the driving pulley

Installing the fixed driving half-pulley

- Insert the spacer.

- Install the fixed driving half-pulley and check that
it is in contact with the spacer and with the guide
bushing of the moving driving pulley.

ENG - 15

Engine Nexus 500 euro 3

- Remove the flat washer and the spring washer
as shown in the figure.

- Insert the nut in the original position (nut side in
contact with the belleville washer).

- Turn the central pulley nut to horizontally align
the holes and install the special tool.

N.B.

CHECK THAT THE STOP WRENCH TOOL IS
EASILY INSERTED INTO THE PULLEY AND IN
THE ENGINE CRANKCASE.

Specific tooling

020474Y Driving pulley lock wrench

- Install the lock ring from the rear so that the
splines are completely engaged.

- Finally install the tool by siding the nuts by hand
and ensuring the tool is resting flatly.

- Tighten the driving pulley fastening nut to the
prescribed torque

- Remove the special tool.

Locking torques (N*m)

Drive pulley nut 160 - 175

ENG - 16

Nexus 500 euro 3 Engine

Installing the roller container

- Install the spacer with the internal chamfer facing
towards the inside.

- Position the rollers on the half-pulley as shown in
the figure.

- The closed side must rest on the inside thrust
face of the roller container.

- Assembly the half-pulley with the roller contrast
plate and sliding blocks.

- Insert the half-pulley on the crankshaft.

- Insert the spacer bushing.

ENG - 17

Engine Nexus 500 euro 3

Refitting the transmission cover

- Install the driving pulley shaft cover, positioning
the tooth gap on the lower part with the reference
mark on the transmission crankcase.

N.B.

ENSURE THAT THE AIR INTAKE AND EXHAUST OPENINGS ARE COMPLETELY FREE.

- Install the outside plastic transmission cover.

- Tighten the 4 fastening screws to the prescribed
torque.

Locking torques (N*m)

Outside transmission cover screws 7 ÷ 9

- Ensure the correct installation on the crankcase
of the 2 centring dowels.

- Insert the transmission cover with the bearing
and install the relevant retainers.

- Lock the four M8 retainers.

Locking torques (N*m)

M8 retainers for transmission cover 23 - 26

ENG - 18