Morini Franco Motori S6-C COMPETITION User manual

SERVICE MANUAL
S6-C COMPETITION
50cc – 2 stroke - liquid cooled

Page 1
S6 /C
ENGINE
INDEX
TECHNICAL SPECIFICATIONS 2
SPECIAL TOOLS 3 - 4
PERIODIC MAINTENANCE 5
LUBRICANTS 6
TROUBLESHOOTING 7 - 14
TIGHTENING TORQUE TABLE 15
ENGINE DISASSEMBLY 16 - 24
ENGINE REASSEMBLY 25 - 37
SPECIAL 3-SHOE CLUTCH DISASSEMBLY/REASSEMBLY 38 - 39
SPECIAL 3-SHOE CLUTCH ADJUSTMENT PROCEDURE 40
ENGINE COMPONENT INSPECTION AND SERVICE 41 - 43
GENERAL PARTS LIST + EXPLODED VIEW TABLES xx

Page 2
S6 /C
ENGINE
SPECIFICATIONS
CYCLE ......................................................... -2stroke
Nr. of CYLINDERS....................................... -1
DISPLACEMENT.......................................... -49.908cc.
BORE AND STROKE mm............. - 39 X 41.8
CYLINDER MATERIAL ................................. - AluminiumwithNi/Sicarbidecoating
COMPRESSION RATIO................................ -(15.5±0.3):1
SPARK PLUG .............................................. -CHAMPIONC53
TIMINGSYSTEM .......................................... -Reed valve with 4 carbon fibre flaps
MAX.R.P.M. .................................................. - 14500 (rpm) MAX
CARBURETOR ............................................ -12/14/19mmdiameter
INTAKE MANIFOLD ..................................... - Adjustable
FUEL............................................................ -EURO UNLEADED NC 623/02 - R.O.N. 95
LUBRICATION OIL MIXER TYPE ................. -2% AGIP2TCITY
LUBRICATION WITH OIL PUMP .................. -On request
IGNITION ...................................................... -Electronicwithmicrochip
PRIMARY DRIVE GEAR ............................... -Straight-toothgearsZ14/59
..................................................................... withsafetycoupling
..................................................................... Ratio1:4,21
SECONDARY DRIVE GEAR......................... - Sprocket Z 10 or Z11
..................................................................... Chaintype 1/2x3/16roller 7.75
CLUTCH ...................................................... -Automaticcentrifugalclutchinoilbath
..................................................................... Adjustable
TRANSMISSION GEAR OIL ......................... -SAE20W quantity250 cc
STARTER...................................................... - Kickstarter
COOLING ...................................................... -With liquid pump
TECNICALSPECIFICATIONS

Page 3
S6 /C
ENGINE
143154
143176
143156
143179
143180
143181
CodeFigure Description
SPECIAL TOOLS
BEARINGINSTALLER
output shaft
BEARINGINSTALLER
crankshaft
BEARINGINSTALLER
output shaft
OILSEAL INSTALLER
output shaft
OILSEAL INSTALLER
crankshaft (flywheel + clutch)
OILSEAL MOUNTING PROTECTION
crankshaft (flywheel + clutch)

Page 4
S6 /C
ENGINE
140558
143162
143155
SPECIAL TOOLS
CodeFigure Description
OIL PUMP SHAFT INSTALLER
(pre-assembled)
FLYWHEEL REMOVER
CRANKCASE PULLER
143294 SPECIAL CLUTCHADJUSTMENTTOOL

Page 5
S6 /C
ENGINE
PERIODICMAINTENANCE
RUNNING-IN RECOMMENDATIONS:
During the running-in period, i.e.forapprox.the first 500 km on theroad,please note as follows:
-Do neverrunthe engineatmaximum revolutions.
-Do never keep thevehicleatmaximum speed.
-Do not keep the engine at idle speed forlonger time.
FIRST MAINTENANCE SERVICE:
to be carried out after 500 - 600 km.
-Replacetheengineoil
-Check the carburation and adjustifnecessary
-Check thetightnessof nutsandbolts.
(Seetable“tighteningtorques”pag.15)

Page 6
S6 /C
ENGINE
LUBRICANTS
N.B.
Use original MORINI FRANCO MOTORI spare parts only
N.B. TRANSMISSION OIL LEVEL CHECK
Remove the oil filler cap on the clutch cover and check the transmission oil level
through window.
RECOMMENDED LUBRICANTS / ADHESIVES
DESCRIPTION CHARACTERISTICS
Transmission oil AGIP RADULA 68 SAE 20W
Assembly of various parts GR/SM2 GREASE
Special assembly GRAPHITISED MOLYCOTE type GREASE
Thread-locking glue LOXEAL 82-21
Clamping glue LOXEAL 83-54

Page 7
S6 /C
ENGINE
TROUBLESHOOTING
Possible CAUSE of the fault
The following flow charts give a general outline of the causes and effects when the engine is not
running correctly.
Descriptions of solutions for a specific cause are general; for more details the reader should
consult the disassembly-reassembly manual.
LEGEND OF SYMBOLS
EFFECT (fault noticed by the user)
Possible general SOLUTION to the fault

Page 8
S6 /C
ENGINE
YES
NO
NO
Starting problems
Faulty spark plug
orwrongsparkplug
heatrating
YES Check spark plug and
replace if necessary.
Engineflooded YES Start the engine with the
throttle fully open.
Removethe spark plug,
revthe engine,installa
dryspark plug and restart
theengine.
The engine
starts
Sparking starts at
highr.p.m. Replace the ignition coil
NO

Page 9
S6 /C
ENGINE
YES
YES
YES
NO
NO
YES
NO
Maximum indicated running
speed cannot be reached
Soiled or
clogged
filter
Disassemble,wash sponge with a
50% solution of petrol and 2T oil;
leave to dry. Clean the filter box
using compressed air; re-
assemble.
Silencer
obstructed Checkthe silencer forclogging.
Replaceif necessary.
Cylinder
exhaustport
soiled with
carbon
deposits
Disassemble the cylinder and check
that the exhaust pipe is clean. If the
exhaust pipe is partly obstructed by
carbon deposits, clean it thoroughly
usingascraper.
Poor
compression
Disassemble the cylinder head,
cylinderandpiston.
Remove the piston rings, place
theminthecylinderlinerandcheck
theamountofwear.
Replaceifexcessivelyworn.