s6 e service manual

S6 / EENGINE

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 23 - 33

OIL MIXER PUMP UNIT 34

ENGINE COMPONENT INSPECTION AND SERVICE 35 - 37

PARTS CATALOGUE xx

S6 / EENGINE

TECHNICAL SPECIFICATIONS

SPECIFICATIONSCYCLE ......................................................... - 2 stroke

Nr. of CYLINDERS....................................... - 1

DISPLACEMENT .......................................... - 49.908 cc.

BORE AND STROKE mm. ................... - 39 X 41.8

CYLINDER MATERIAL .................................. - Special cast iron

COMPRESSION RATIO ................................ - (11 ±0.6) : 1

SPARK PLUG ............................................... - CHAMPION L78 C

TIMING SYSTEM .......................................... - Reed valve in crankcase with 3 metal

..................................................................... flaps

MAX. R.P.M. .................................................. - 9000

CARBURETOR ............................................ - 12 mm diameter or equivalent

INTAKE MANIFOLD ..................................... - Fixed

FUEL ............................................................ - EURO UNLEADED NC 623/02 - R.O.N. 95........................................................................... plus 2% oil

LUBRICATION MIXER OIL TYPE ................. - AGIP 2T CITY

LUBRICATION SYSTEM .............................. - automatic oil mixer pump (on request)

GENERATOR ............................................... - (on request)

IGNITION ...................................................... - Inductive electronic

PRIMARY DRIVE GEAR ................................ - Straight-tooth gears Z 14/59

..................................................................... with safety coupling

SECONDARY DRIVE GEAR......................... - Sprocket Z 10 or Z11

..................................................................... chain type 1/2 x 3/16 roller 7.75

CLUTCH ...................................................... - Automatic centrifugal 2-shoe clutch in oil

..................................................................... bath

TRANSMISSION GEAR OIL ......................... - AGIP RADULA 68 type SAE 20 W

..................................................................... quantity 200 cc

STARTER...................................................... - Kick starter

COOLING ...................................................... - Air cooled

S6 / EENGINE

143154

143176

143156

143179

143180

143181

SPECIAL TOOLS

BEARING INSTALLERcrankshaft

BEARING INSTALLERoutput shaft

OIL SEAL INSTALLERcrankshaft (flywheel + clutch)

OIL SEAL INSTALLERoutput shaft

BEARING INSTALLER output shaft

CodeFigure Description

OIL SEAL MOUNTING PROTECTIONcrankshaft (flywheel + clutch)

S6 / EENGINE

140558

143162

143155

SPECIAL TOOLS

OIL PUMP SHAFT INSTALLER(pre-assembled)

CodeFigure Description

FLYWHEEL REMOVER

CRANKCASE PULLER

S6 / EENGINE

PERIODIC MAINTENANCE

RUNNING-IN RECOMMENDATIONS:

During the running-in period, i.e. for approx. the first 500 km on the road, please note as follows:- Do never run the engine at maximum revolutions.- Do never keep the vehicle at maximum speed.- Do not keep the engine at idle speed for longer time.

FIRST MAINTENANCE SERVICE:

to be carried out after 500 - 600 km.

- Replace the engine oil- Check the carburation and adjust if necessary- Check the tightness of nuts and bolts(See table “tightening torques” page 15)

S6 / EENGINE

LUBRICANTS

N.B.Use original MORINI FRANCO MOTORI spare parts only

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

N.B. TRANSMISSION OIL LEVEL CHECKRemove the oil filler cap on the clutch cover and check the transmission oil levelthrough window.

S6 / EENGINE

TROUBLESHOOTING

The following flow charts give a general outline of the causes and effects when the engine is notrunning correctly.Descriptions of solutions for a specific cause are general; for more details the reader shouldconsult the disassembly-reassembly manual.

LEGEND OF SYMBOLS

EFFECT (fault noticed by the user)

Possible CAUSE of the fault

Possible general SOLUTION to the fault

S6 / EENGINE

Starting problems

Faulty spark plugor wrong spark plug

heat rating

Engine flooded

Sparking starts at ahigh r.p.m.

Check spark plug andreplace if necessary.

Start the engine with thethrottle fully open.

The enginestarts

Remove the spark plug,rev the engine, install adry spark plug andrestart the engine.

Replace the ignition coil

YES

YES

YES

NO

NONO

S6 / EENGINE

Maximum indicated runningspeed cannot be reached

Soiled orclogged

filter

Cylinder exhaust port soiled with carbon

deposits

Silencerobstructed

Poorcompression

YES

YES

YES

NO

NO

Disassemble, wash sponge with a50:50 solution of petrol and 2T oil;leave to dry. Clean the filter boxusing compressed air;re-assemble.

Disassemble the cylinder and checkthat the exhaust pipe is clean. If theexhaust pipe is partly obstructed bycarbon deposits, clean it thoroughlyusing a scraper.

Check the silencer for clogging.Replace if necessary.

Disassemble the cylinder head,cylinder and piston.Remove the piston rings, placethem in the cylinder liner and checkthe amount of wear.Replace if excessively worn.

YES

NO

S6 / EENGINE

Poor acceleration/pickup

Clutch

Irregularacceleration

YES

YES

NO

Check the clutch shoe thicknessand the clutch springs forstretching.If either is excessively worn theyshould be replaced.

Check the exact number of turnsof the air adjusting screw on thecarburetor.

S6 / EENGINE

Idling speedtoo high or

too low

False airintake fromcarburetormanifold

YES

YES

YES

YES

NO

Disassemble the carburetor andclean all the parts (nozzles, throttlevalve, jet needle, float chamberand casing) with solvent and dryusing compressed air.

Adjust the RPM of the idling speed(with engine warm) by adjusting thescrew on the throttle valve of thecarburetor.

Check the integrity of thecarburetor manifold gaskets.

NO

Incorrect idling speed

Check the integrity of the rubbercoupling sleeve that connectscarburetor and air filter box.

Check the reed valve gasket

False airintake

from enginecrankshaftoil seals

Check the integrity of thecrankshaft oil seals. Replaceeven if only slightly damaged.

YES

YES

S6 / EENGINE

Noisy engine

Incorrecttransmission

gearsassembly

Loosetransmission

nut

Transmissionnoise and rearwheel drag atidling speed.

YES

YES

NO

NO

Check the assembly of all gears andparts of the transmission.

Check the clutch unitYES

Check the tightening torque of theclutch nut.

S6 / EENGINE

Noisy engine

Noisy gearsYES

YES

YES

YES

NO

NO

Check the oil level.Refill if necessary.

BEARING INSPECTIONRotate the bearing inner race byfinger to inspect for abnormal play,noise and smooth rotation while thebearings are mounted in thecrankcase.Replace the bearing if anythingunsual is found.

Check the clearance between thepiston and the cylinder. If it doesnot correspond to the prescribedvalue, grind the cylinder andassemble 1st oversize piston.

Check the teeth of the drive gearsvisually.Replace if signs of damage or wearare evident.

Noisycylinder

unit

Noisycrankshaftbearings

S6 / EENGINE

Smokey exhaust

Oil mixerpump

YES

YES

YES

NO

NO

Disassemble the cylinder andremove any carbon deposits;check the silencer for clogging.

Check that the oil is 100%synthetic for separate oil mixerpump use.

Carbondeposits

Disassemble the oil mixer pumpand check the flow rate.

Mixer oil

YES

NO

Replace the fuel in the tank withnew fuel mixed with 2% of thetype of oil indicated in thehandbook.

Percentage ofmixer oil

S6 / EENGINE

TIGHTENING TORQUE TABLE

DENOMINATION TORQUE(Nm)

Crankcase bolts 10 - 12

Clutch cover bolts 10 - 12

Flywheel cover bolts 3 - 4

Carburetor manifold bolts 7 - 8

Ignition coil clamping screws 6 - 8

Oil mixer pump clamping screws(for model with mixer only) 5 - 6

Carburetor clamping screw 4 - 5

Starter lever bolt 8 - 10

Oil drain plug 8 - 10

Clutch nut 50 - 55

Flywheel nut 25 - 30

Head nuts 12 - 14

Spark plug 20 - 25

S6 / E

ENGINE

TOOLCODEDIAGRAM DESCRIPTION NOTES

CARBURETOR - CYLINDER HEAD - CYLINDER - PISTON

Disassemble the CARBURETOR

Remove the SPARK PLUG

Loosen the SCREWS and remove theCARBURETOR MANIFOLD includingthe REED VALVE.

Disassemble the CYLINDER HEADand remove the HEAD-CYLINDERGASKET

Remove the CYLINDER

ENGINE DISASSEMBLY

S6 / E

ENGINE

Disassembly the CIRCLIPS and thePISTON PIN.Remove the PISTON and theROLLER CAGE.

Remove the CYLINDER BASE GASKET

Disassemble the SPARK COIL

Loosen the clamping BOLTS andremove the FLYWHEEL COVER

FLYWHEEL SIDE

MIND THE BRACKETINSIDE THE COVER



S6 / E

ENGINE

Disassemble the SNAP RING

Disassemble the FLYWHEELROTOR (compass tool + flywheelremover)

Remove the SPROCKET from theOUTPUT SHAFT

140558


S6 / E

ENGINE

MAKE SURE TODRAIN THE ENGINECOMPLETELY

Compass toolCLAMPED WITH

LOXEAL

CLUTCH SIDE

Remove the SPECIAL FRONT-CLUTCH NUT and the BELLEVILLEWASHER

Remove the OIL DRAIN PLUG(cross-headed)

Loosen the clamping BOLTS on thecover and remove the CLUTCHCOVER


S6 / E

ENGINE

Disassemble the CLUTCH and the2.5mm SPACER RING

Remove the CLUTCH BELL andSPACER RING


S6 / E

ENGINE

CRANKCASE “OPENING”

Remove the cylinder STUD BOLTS ifnecessary BLOCKED WITH

LOXEAL

Remove the 8 CRANKCASE BOLTS

Open the CRANKCASE

Remove the DOWEL PINS and theCRANKCASE GASKET.Remove the crankshaft if necessary

THE CRANKSHAFTIS DRIVEN ONTOTHE BEARINGS.OPEN THECRANKCASE FROMFLYWHEEL SIDEUSING THEPULLER TOOL

143162


S6 / E

ENGINE

To replace the CRANKSHAFTBEARING and the OUTPUT SHAFTROLLER CAGE (flywheel side) followthe same procedure as describedabove.

Remove the OUTPUT SHAFT SNAPRING.

Remove the OUTPUT SHAFT.

Inspect the OUTPUT SHAFTBEARING for abnormal play andnoise.Replace the bearing if anythingunusual occurs.

Remove the SNAP RING.

THE BEARING ISDRIVEN INTO THEBEARING HOUSING


Remove the BEARING by using astandard bearing remover set.

S6 / E

ENGINE

ENGINE REASSEMBLY

CRANKCASE PREASSEMBLY

143176

143154

143156


Drive the OUTPUT SHAFT BEARINGinto the half crankcase clutch side andsecure with the snap ring

LUBRICATE THEHOUSING

LEAVE THE PRINTON THE BEARING

VISIBLE

Drive the CRANKSHAFT BEARINGSinto the half crankcase clutch side andinto the half crankcase flywheel side.



VISIBLE

Drive the ROLLER CAGE OUTPUTSHAFT into the half crankcaseflywheel side.



VISIBLE

S6 / E

ENGINE

CRANKCASE “CLOSING”

Insert the DRIVE SHAFT in the halfcrankcase clucth side

Insert the SNAP RING onto thesecond output shaft slot (neartransmission gear)

Insert the OUTPUT SHAFT into the halfcrankcase clutch side and secure withSNAP RING

Insert the DOWEL PINS



S6 / E

ENGINE

Fix 1 x BOLT M6X60 in the postionbetween the stud bolts and the reedvalve zone.

143179143180143181

Lubricate the CRANKCASE GASKETon both sides.

Apply the CRANKCASE GASKET onthe half crankcase clutch side usingthe 2 dowel pins for centering.

Assembly the HALF CRANKCASES

Grease the oil seal housing and theoil seal lip carefully.

Install the CRANKSHAFT OIL SEALRINGS and the OUTPUT SHAFT OILSEAL RING.

Trim the crankcase gasket (cylinderzone and carburetor zone.)

Fix the remaining 7 X BOLTS M6X50.Cross-tighten the bolts using atightening torque of 10-12 Nm.Check to make sure that thecrankshaft and output shaft rotatesmootly.

DO NOT TIGHTEN


GREASE TYPEGR/SM2

S6 / E

ENGINE

FLYWHEEL SIDE

Mount the SPROCKET and securewith the SNAP RING

Caulk the key seat on the crankshaftand insert the FLYWHEEL KEY.

Clean and remove all traces of greasefrom the rotor cone and the drive shaftcone.Assemble the flywheel rotor using thekey as reference.

Assemble the FLYWHEEL NUT andtighten.

Compass tool

Assemble the IGNITION COIL and fitthe 2 BOLTS without tightening them.

Check the clearance between theignition coil and the flywheel rotorusing a thickness gauge:CLEARANCE = 0.35 - 0.45 mm.

Tighten the bolts.

DO NOT TIGHTEN


Tightening torque25 - 30 Nm


S6 / E

ENGINE

FLYWHEEL COVER

Drive in the 2 elastic dowel pins inthe cover. and make sure that theydo NOT INTERFERE with thebracket mounting face.

Assemble the BRACKET on theflywheel cover.

Secure the FLYWHEEL COVER using:3 SCREWS M5X50 + WASHER.Tightening torque 3-4 N.m.1 SCREW M5X20 + WASHER.Tightening torque 3-4 N.m.

Assemble the FLYWHEEL COVERplacing the rubber fairleads in theirseats on the cover.


S6 / E

ENGINE

CYLINDER - PISTON - CYLINDER HEAD

Insert the CYLINDER BASE GASKET

Insert the CYLINDER HEADGASKET

Assemble the CYLINDER

Assemble the ROLLER CAGE,PISTON and PISTON PIN andsecure with CIRCLIPS.

BEFOREASSEMBLY

CHECKTHE SIZE CODE OF

THE CYLINDERAND THE PISTON


WHENINSTALLING THEPISTON TURNTHE ARROWMARK ON THEHEAD OF THEPISTON TO THEEXHAUST SIDEOIL THE PISTON.

ALWAYS ASSEMBLE ROLLERCAGE SIZE - 2 - 4

S6 / E

ENGINE


Fit the 4 CYLINDER HEAD NUTSand cross tighten.


Install the SPARK PLUG and tighten Tightening torque20 - 25 Nm

CARBURETOR UNIT

Insert the CARBURETOR MANIFOLDBASE including the REED VALVE.

Assemble the CARBURETORMANIFOLD on the base and securewith 4 BOLTS M6X20.


Tightening torque7 - 8 Nm.

Assemble the CARBURETOR andtighten the CLAMP SCREW.

Tightening torque3 - 4 Nm.

S6 / E

ENGINE

CLUTCH COVER

Assemble the SPRING on the slidinggear as shown on the figure.

Lubricate the inside of the spring usingGR MU/3 grease.

Assemble the SLIDING GEAR on thecover and secure the SPRINGbetween the two stops.

Assemble the SPACER RING andO-RING on the KICK STARTERSHAFT.

Lubricate the O-ring area usingGR MU/3 grease.

Lubricate the KICK STARTERSHAFT in the clutch cover operatingzone using grease type MOLYCOTE.Install KICK STARTER SHAFT in theclutch cover and make sure that thegear section is engaged properly withthe sliding gear.After assembly check that the springof the sliding gear is correctly


143167

S6 / E

ENGINE

Install and load the RETURN SPRINGon the kick starter shaft.

Secure the spring on the backstop inthe clutch cover.

Assemble the SPRING WASHER andsecure with the SNAP RING.

Place the SPACER on the kick startershaft and secure with the snap ring.

Assemble the KICK STARTER LEVERand fasten by using the bolt M7x25.

KICK STARTER LEVER POSITION*Steel lever = 109°*Aluminium lever = 96°

Check axial clearance: 0.1 - 0.3 mm


Tightening torque8-10 N.m.

KICK STARTER LEVER POSITION

*Aluminium lever = 96°*Steel lever = 109°

S6 / E

ENGINE

CLUTCH SIDE

CAUTIONTHE PRINT ONTHE CLUTCH

SHOE AND THEREFERENCE MARK

ON THE HUBMUST BE ON THESAME SIDE AND

LEFT VISIBLE

Insert the 0.8mm SPACER RING onthe crankshaft clutch side.

Lubricate the clutch bell operating zoneof the crankshaft using the grease typeROCOL ASP MOLYCOTE.

Install the CLUTCH BELL

Insert the 2.5 mm SPACER RING

Install the CLUTCH on the crankshaft

Insert the BELLEVILLE WASHERand clamp the clutch using theSPECIAL FRONT CLUTCH NUT.(LEFT HAND THREAD)

Add LOXEAL 83-54 to the clutch nutand tighten

Tightening torque 50-55 N.m.

Check the axial clearance of theclutch bell: 0.3 - 0.5 mm

Assemble the clutch cover gasket.

CAUTION

In order to avoidany clutch hubjamming on thespline shaft and toensure any futuredisassemblyoperation of theclutch unit, makesure to applyLOXEAL 83-54exclusively on thecluth nut and NOTon shaft end.

Compass tool


S6 / E

ENGINE

Tightening torque10-12 N.m.

Tightening torque8 - 10 N.m.

RecommendedOil type:

AGIP RADULA 68SAE 20W

Mount the clutch cover and securewith 6 BOLTS M6 x 30.

Insert the OIL DRAIN PLUG +WASHER and tighten.

Pour 200 cc of oil type AGIPRADULA 68 SAE 20W and fit theOIL FILLER CAP + GASKET.

AFTER COMPLETED ASSEMBLYCHECK THAT THE ENGINEROTATES SMOOTHLY


S6 / E

ENGINE

143155

143342

S6 OIL MIXER PUMP

Preassemble the 2 BEARINGS andSPACER on the OIL MIXER PUMPDRIVE SHAFT and secure with 2SNAP RINGS.

The print on the bearings should facethe drive end of the shaft.

Lubricate the bearing housing.Drive the OIL MIXER PUMP DRIVESHAFT UNIT into the half crankcaseflywheel side.

Insert the CLEARANCE SPACER.Assemble the BEARING SNAPRING.

Insert the DRIVE BELT onto theDRIVEN PULLEY.

Install the pulley on the oil mixer pumpshaft and the drive belt onto the splinedpart of the crankshaft.

Assemble the oil mixer pump on thesupport bracket and tighten thescrew M5x12.

In order to simplify the assemblyoperation of the oil mixer pump,make sure that the timing of thedriven pulley and the oil mixerpump shaft do match.

Install the BRACKET with OILMIXER PUMP into the housing of thehalf crankcase flywheel side.



S6/EENGINE

CYLINDER - PISTON TABLE

ENGINE COMPONENT INSPECTION AND SERVICE

PartValue (mm)

50cc

CylinderPistonPiston rings :1)Piston ring 1st slot2)Piston ring 2nd slot

Ø 39Ø 39

Ø 39 x 2 - 0.01 - 0.025Ø 39 x 1.25 - 0.01 - 0.025

S6/EENGINE

CYLINDER - PISTONASSEMBLY SELECTION TABLE

CHECK POSITIONFor correct dimension control

+ 0,026

+ 0,021

+ 0,020

+ 0,016

+ 0,015

+ 0,010

+ 0,009

+ 0,004

- 0,036

- 0,041

- 0,046

- 0,047

- 0,052

- 0,053

- 0,058

- 0,040

SIZE CODE(stamped on part)

CYLINDER - PISTONDIMENSIONS ASSEMBLY

CLEARANCECYLINDER PISTON

A (RED) ø 39 ø 39

B (YELLOW) ø 39 ø 39 0.050-0.067mm

C(NEUTRAL) ø 39 ø 39

D (GREEN) ø 39 ø 39

S6/EENGINE

+0,18

CYLINDER CHECK-Check the internal surface of the cylinder for signs of seizure or abnormal wear.-Measure the internal diameter of the cylinder using a bore gauge.-Wear limit: Minimum indicated cylinder selection diameter + 0.03mm.-Take measurements in three different positions along the axis of the cylinder.-In each position take two measurements, one parallel with and the other perpendicular to the crankshaft axis.

PISTON CHECK

-Remove the piston rings and check the piston for abnormal signs and wear.

N.B.The piston rings are fragile, handle with care.

RING-TO-GROOVE MEASUREMENT.Wear limit: 0,08 mm max.

PISTON BORE MEASUREMENT.-Maximum permitted diameter:12 + 0,18 mm

-Measure the piston outside diameter in the direction perpendicular to the piston axis at 14,5 mm from the skirt.

s6 e service manual

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