PIAGGIO MSS Fly 50 4T Instruction manual

WORKSHOP MANUAL
633212
MSS Fly 50 4T

WORKSHOP
MANUAL
MSS Fly 50 4T
The descriptions and illustrations given in this publication are not binding. While the basic specifications
as described and illustrated in this booklet 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 models
should be checked at the official Piaggio sales network.
"©Copyright2007-PIAGGIO&C.S.p.A.Pontedera.Allrightsreserved.Reproductionofthispublication
in whole or in part is prohibited."
PIAGGIO & C. S.p.A. - After sales
V.le Rinaldo Piaggio, 23 - 56025 PONTEDERA (Pi)

WORKSHOP MANUAL
MSS Fly 50 4T
This workshop manual has been drawn up by Piaggio & C. Spa to be used by the workshops of Piaggio-
Gilera 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 Sectionsmarked with this symbol indicatethe correct use of thevehicle
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

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 well-
ventilated, 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 open 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 measurement. Using unsuitable
coupling members and tools may damage the vehicle.
- When carrying out maintenance operations on the vehicle that involve the electrical system, make
suretheelectricconnectionshavebeenmadeproperly,particularlythegroundandbatteryconnections.
MSS Fly 50 4T Characteristics
CHAR - 7

Vehicle identification
VEHICLE IDENTIFICATION
Specification Desc./Quantity
Engine prefix C442M ÷ 1001
Chassis prefix ZAPM44200 ÷ 1001
Dimensions and mass
WEIGHT AND DIMENSIONS
Specification Desc./Quantity
Length 1,880
Maximum height 1150 mm
Seat height 785
Width 735
Wheelbase 1,340
Kerb weight 105 kg
Characteristics MSS Fly 50 4T
CHAR - 8

Engine
ENGINE
Specification Desc./Quantity
Engine type Single cylinder 4-stroke Piaggio Hi-PER4
Bore x stroke 39 X 41.8 mm
Cubic capacity 49.93 cm³
Compression ratio 11.5 :1
Timing system single overhead camshaft, driven by a chain to the left side.
Depression carburettor KEIHN CVK 18
CO adjustment 3,2% ± 0,5
Engine idle 1900 ÷ 2000 rpm.
Air filter Sponge, soaked in a mixture (50% SELENIA Air Filter Oil and
50% unleaded petrol).
Starting system electric starter/kick-starter
Lubrication Engine lubrication with lobe pump (inside the crankcase),
chain-driven, and double filter: mesh and centrifugal.
Fuel supply Gravity feed, with unleaded petrol (with a minimum octane rat-
ing of 95) with carburettor.
Max. power (crankshaft) 2,5 KW (3,4 CV) at 6500 rpm.
Cooling system forced coolant circulation system
Valve clearance intake: 0.10 mm discharge: 0.15 mm
MSS Fly 50 4T Characteristics
CHAR - 9

Transmission
TRANSMISSION
Specification Desc./Quantity
Transmission With automatic expandable pulley variator, torque server, V-
belt, automatic clutch, gear reduction unit.
Capacities
CAPACITY
Specification Desc./Quantity
Rear hub oil Quantity: approx. 85 cc
Engine oil Capacity: approx. 850 cm³
Fuel tank capacity approx. 7.2 litres (of which 1.5 l is reserve)
Electrical system
IMPIANTO ELETTRICO
Specification Desc./Quantity
Type of ignition Capacitive discharge type electronic ignition, with incorporated
high voltage coil
Ignition advance variable, with microprocessor (before T.D.C.) 10° at 1800-2000 rpm
26° at 5000-6000 rpm
Spark plug Champion RG 4 PHP
Champion RG 4 HC
Alternative spark plug DENSO U24ESR-NB
Battery 12V-9Ah
Fuse 10A
Generator single-phase alternating current
Frame and suspensions
FRAME AND SUSPENSION
Specification Desc./Quantity
Type of chassis Welded tubular steel chassis with stamped sheet reinforce-
ments.
Front suspension Telescopic mechanical fork, 76-mm travel.
Rear suspension Single hydraulic shock absorber, 72.5-mm travel
Brakes
BRAKES
Specification Desc./Quantity
Front brake Disc brake (Ø 200 mm) with hydraulic control (lever on the right
end of the handlebar) and floating calliper.
Rear brake drum brake (Ø 140 mm) with mechanical linkage.(l.h. brake
lever).
Characteristics MSS Fly 50 4T
CHAR - 10

Wheels and tyres
WHEELS AND TYRES
Specification Desc./Quantity
Front wheel rim Die-cast aluminium alloy 3.50 x 12"
Front tyre Tubeless, 120/70-12"
Rear wheel rim Die-cast aluminium alloy: 3.00"x12"
Rear tyre Tubeless, 120/70 - 12"
Front tyre pressure 1.8 bar
Rear tyre pressure 2 bar
Rear wheel pressure (rider and passenger): 2.3 bar
N.B.
CHECK AND ADJUST TYRE PRESSURE WITH TYRES AT AMBIENT TEMPERATURE. ADJUST
PRESSURE ACCORDING TO THE WEIGHT OF RIDER AND ACCESSORIES.
Secondary air
•The SAS (Secondary air housing) op-
erating principle for 50 4T engines is
similar to that for 50 2T engines; the
only difference lies in how air is sucked
in the external and the external side of
the transmission compartment.
•Air is taken in along tube «A» (to the
cylinder side) and, after been cleaned
throughthefilter«B»,getsintothereed
valve «C» to be directed towards the
head through a flexible pipe and then a
rigid one «D» flanged to the head. In
this way, the air reaches the discharge
pipe to increase the amount of oxygen
in the unburned gases before the cat-
alytic converter, thus helping a better
reaction of this device.
Carburettor
50cc Version
MSS Fly 50 4T Characteristics
CHAR - 11

Kehin
KEHIN CARBURETTOR
Specification Desc./Quantity
Type CVK 18
Throttle valve diameter: Ø 18,5
Choke diameter Ø 17
Marking on body: Z61B
Maximum thrust 75
Maximum air thrust (on body) Ø1,1
Marking on conical needle: NGBA
Throttle spring: 100 ÷ 159 gr
Minimum thrust 35
Idle air jet (on body): Ø 1,4
Initial opening - idle mixture screw: 1 3/4
Starter jet 40
Starter air nozzle (on the body): Ø 1.5
Choke needle travel: 11,5 mm
Tightening Torques
FRONT BRAKE
Name Torque in Nm
Brake fluid pump - hose fitting 16 ÷20 Nm
Brake fluid pipe-calliper fitting 19 ÷ 24
Calliper tightening screw 24 ÷ 27
Disc tightening screw 8 ÷ 10
Oil bleed screw 7 ÷ 10
FRONT SUSPENSION
Name Torque in Nm
Lower fork fixing screw 15 ÷ 20
Front wheel axle nut 45 - 50
STEERING ASSEMBLY
Name Torque in Nm
Upper steering ring nut 35 ÷ 40
Steering lower ring nut 8 ÷ 10
Handlebar fixing screw 50 ÷ 55
CHASSIS
Name Torque in Nm
Swinging arm - engine pin* 33 ÷ 41
Frame/swing-arm bolt (*) 64÷72
Shock absorber - chassis nut (*) 20 to 25 Nm
shock absorber - engine pin (*) 33 to 41 N·m
Rear wheel axle (*) 104÷126 N·m
Centre-stand mounting bracket bolt 25÷30 N·m
Centre-stand mounting bracket screw 20÷25 N·m
Side stand fixing screw 12 ÷ 20
Side stand bracket fixing screw 15 ÷ 20
Overhaul data
Assembly clearances
Characteristics MSS Fly 50 4T
CHAR - 12

Cylinder - piston assy.
CONNECTION PISTON AND CYLINDER
Name Initials Cylinder Piston Play on fitting
Cylinder (with asso pis-
ton/right way) A 38,993 ÷ 39,000 38,954 ÷ 38,961 0.032 ÷ 0.046
Cylinder (with shiram
piston) A 38,993 ÷ 39,000 38,949 ÷ 38,956 0.037 ÷ 0.051
Cylinder (with asso pis-
ton/right way) B 39,000 ÷ 39,007 38,961 ÷ 38,968 0.032 ÷ 0.046
Cylinder (with shiram
piston) B 39,000 ÷ 39,007 38,956 ÷ 38,966 0.037 ÷ 0.051
Asso piston/right way
(with asso cylinder/right
way)
C 39,007 ÷ 39,014 38,968 ÷ 38,975 0,032 ÷ 0,046
Asso piston/right way
(with shiram cylinder) C 39,007 ÷ 39,014 38,963 ÷ 38,970 0,037 ÷ 0,051
Shiram piston (with as-
so cylinder/right way) D 39,014 ÷ 39,021 38,975 ÷ 38,982 0,032 ÷ 0,046
Shirampiston(withshir-
am cylinder) D 39,014 ÷ 39,021 38,970 ÷ 38,977 0,037 ÷ 0,051
Cylinder 1st oversize A1 39.193 ÷ 39.200 39.154 ÷ 39.161 0.032 ÷ 0.046
Cylinder 1st oversize B1 39.200 ÷ 39.207 39.161 ÷ 39.168 0.032 ÷ 0.046
Piston 1st oversize C1 39.207 ÷ 39.214 39.168 ÷ 39.175 0.032 ÷ 0.046
Piston 1st oversize D1 39.214 ÷ 39.221 39.175 ÷ 39.182 0.032 ÷ 0.046
Cylinder 2nd oversize A2 39.393 ÷ 39.400 39.354 ÷ 39.361 0.032 ÷ 0.046
Cylinder 2nd oversize B2 39.400 ÷ 39.407 39.361 ÷ 39.368 0.032 ÷ 0.046
Piston 2nd oversize C2 39.407 ÷ 39.414 39.368 ÷ 39.375 0.032 ÷ 0.046
Piston 2nd oversize D2 39.414 ÷ 39.421 39.375 ÷ 39.382 0.032 ÷ 0.046
Cylinder 3rd oversize A3 39.593 ÷ 39.600 39.554 ÷ 39.561 0.032 ÷ 0.046
Cylinder 3rd oversize B3 39.600 ÷ 39.607 39.561 ÷ 39.568 0.032 ÷ 0.046
Piston 3rd oversize C3 39.607 ÷ 39.614 39.568 ÷ 39.575 0.032 ÷ 0.046
Piston 3rd oversize D3 39.614 ÷ 39.621 39.575 ÷ 39.582 0.032 ÷ 0.046
MSS Fly 50 4T Characteristics
CHAR - 13

Piston rings
SEAL RINGS
Name Description Dimensions Initials Quantity
1st Compression ring 39 x 1 A 0.08 ÷ 0.20
2nd Compression ring 39 x 1 A 0.05 ÷ 0.20
Oil scraper ring 39 x 2 A 0.20 ÷ 0.70
1st Compression ring
1st Oversize 39.2 x 1 A 0.08 ÷ 0.20
2nd Compression ring
1st Oversize 39.2 x 1 A 0.05 ÷ 0.20
Oil scraper ring 1st
Oversize 39.2 x 2 A 0.20 ÷ 0.70
1st Compression ring
2nd Oversize 39.4 x 1 A 0.08 ÷ 0.20
2nd Compression ring
2nd Oversize 39.4 x 1 A 0.05 ÷ 0.20
Oil scraper ring 2nd
Oversize 39.4 x 2 A 0.20 ÷ 0.70
1st Compression ring
3rd Oversize 39.6 x 1 A 0.08 ÷ 0.20
2nd Compression ring
3rd Oversize 39.6 x 1 A 0.05 ÷ 0.20
Oil scraper ring 3rd
Oversize 39.6 x 2 A 0.20 ÷ 0.70
Characteristics MSS Fly 50 4T
CHAR - 14

Crankcase - crankshaft - connecting rod
END PLAY BETWEEN DRIVING SHAFT AND CONNECTING ROD
Name Description Dimensions Initials Quantity
Half-shaft, transmission
side 14 +0 -0.005 A
Flywheel-side half-shaft 16 +0 -0.005 B
Connecting rod 14.8 +0.05 -0 C
Spacer tool 45.00/ Fits andclearan-
ces D = 0.15 ÷ 0.30 E
Slot packing system
N.B.
MEASUREMENT "A" TO BE TAKEN IS A VALUE OF PISTON RE-ENTRY, IT INDICATES BY HOW
MUCH THE PLANE FORMED BY THE PISTON CROWN FALLS BELOW THE PLANE FORMED BY
THE TOP OF THE CYLINDER. THE FURTHER THE PISTON GETS INSIDE THE CYLINDER, THE
THINNER THE HEAD GASKET TO BE APPLIED SHOULD BE (TO RECOVER THE COMPRESSION
RATIO) AND VICE VERSA.
Characteristic
Shimming system to control the compression ratio
CR: 11.1 ÷ 12.9
PISTON PROTRUSION CHECK
Name Measure A Thickness
shimming_1 0.05 ÷ 0.25 0.35
shimming_2 0.25 ÷ 0.40 0.25
MSS Fly 50 4T Characteristics
CHAR - 15

Products
TABLE OF RECOMMENDED PRODUCTS
Product Description Specifications
AGIP ROTRA 80W-90 rear hub oil SAE 80W/90 Oil that exceeds the re-
quirements of API GL3 specifications
AGIP CITY HI TEC 4T Oil to lubricate flexible transmissions
(brakes, throttle control and odometer) Oil for 4-stroke engines
AGIP FILTER OIL Oil for air filter sponge Mineral oil with specific additives for in-
creased adhesiveness
AGIP GP 330 Grease (brake control levers, throttle
grip) Calcium complex soap-based grease with NLGI 2; ISO-L-XBCIB2
AGIP CITY HI TEC 4T Engine oil SAE5W-40,APISL,ACEAA3,JASOMA
Synthetic oil
AGIP BRAKE 4 Brake fluid FMVSS DOT 4 Synthetic fluid
MONTBLANC MOLYBDENUM
GREASE Grease for driven pulley shaft adjusting ring and movable driven pulley housing Grease with Molybdenum disulphide
AGIP GREASE PV2 Grease for the steering bearings, pin
seats and swinging arm White anhydrous-calcium based grease to protect roller bearings; temperature
range between -20 C and +120 C; NLGI
2; ISO-L-XBCIB2.
AGIP GREASE SM 2 Grease for odometer transmission gear
case Lithium grease with NLGI 2 molybdenum disulphide; ISO-L-XBCHB2, DIN
KF2K-20
Characteristics MSS Fly 50 4T
CHAR - 16

INDEX OF TOPICS
TOOLING TOOL

TOOLS
Stores code Description
001330Y Tool for fitting steering seats
001467Y008 Pliers to extract 17 mm ø bearings
001467Y009 Driver for OD 42-mm bearings
004499Y Camshaft bearing extractor
005095Y Engine support
008119Y009 Tube to assemble shafts and axles
Tooling MSS Fly 50 4T
TOOL - 18

Stores code Description
020004Y Punch for removing fifth wheels from
headstock
020055Y Wrench for steering tube ring nut
020150Y Air heater support
020151Y Air heater
020162Y Flywheel extractor
020171Y Punch for Ø 17 mm roller case
MSS Fly 50 4T Tooling
TOOL - 19

Stores code Description
020265Y Bearing fitting base
020288Y Fork to assemble piston on cylinder
020291Y Valve fitting/ removal tool
020306Y Punch for assembling valve sealing rings
020329Y MityVac vacuum-operated pump
020330Y Stroboscopic light to check timing
Tooling MSS Fly 50 4T
TOOL - 20