Yingang YG125-30B User manual

YG125-30B MaintenanceManual Foreword
1
Foreword
Withtheeverincreasingvarietiesofmotorcycles,newstructuresandnewtechniqueshaveincreasinglybeenapplied.
TohelpYINGANGTECHNOLOGYCo.,Ltdusersandmaintenancepersonnelbetterunderstandthemaintenance,
adjustmentandrepairtechniquesofYG125-30Amotorcycle,wepreparedthismaintenancemanual.Thismanualis
expectedtofacilitatetheYINGANGTECHNOLOGYCo.,Ltdusersandmaintenancepersonnelandprovidetechnical
guidanceforthem.
ThemasterstrokeofthemanualistheYG125-30Amotorcycle,andthecontentsinChapter1-Chapter3areapplicable
totheadjustmentofvariouspartsofthemotorcycle.Chapter4-18describesvariousconstitutingpartsofthemotorcycle
respectively.Chapter19containstheelectricalsystemdiagram.
Thestandardmaintenanceprocedures,maintenanceprecautionsandgeneralmaintenanceknowledgearenot
coveredinthismanual.Anyuserormaintenancepersonnelwhoneedstheaboveinformationmayrefertotherelated
materials
Allmaterials,chartsandvariousdata,aswellasperformanceindicesreferencedherein,areforthelatestmodelinour
productfamilyatthedatethismanualisprinted.YINGANGTECHNOLOGYCo.,Ltd. shallhavetheright to,atanytime,
amendthismanualwithoutpriornotice.ThecopyrightofallpartsofthismanualbelongstoChinaYINGANG
TECHNOLOGYCo.,Ltd. andnounitsorindividualsareallowedtoreprintitthewithoutconsentofourcompany.
Wehopeyouwillenjoythecomfortandpleasureitbringstoyouduringyourdriving!

YG125-30B MaintenanceManual Contents
2
Contents
1. Overview 1-12
2. Lubricationsystem 13-23
3. Inspectionandadjustment 24-39
4. Fuelsystem 40-45
5. Removalandinstallationofengine 46-50
6. Cylinderhead,cylinderandpiston 51-67
7. ClutchandRightcrankcasecover 68-78
8. Magnetoandstartingsystem 79-87
9. Crankcase,crankshaftandShiftmechanism 88-104
10. Frameandexhaustsystem 105-109
11. Frontwheel,frontoverhangandsteeringstem 110-121
12. Rearwheelandrearoverhang 122-127
13. Generalremarksofelectricalsystem 128
14. Powersupplysystem 129-131
15. Startingsystem 132-134
16. Illuminationsignalsystem 135-140
17. Electricalstartingcontrolsystem 141-144
18. Enginemanagementsystem 145-156
19. ElectricalSystemDiagram 157
EngineVehicle body
Electrical system Overview

YG125-30B Maintenance Manual Overview
1
1Overview
EngineNumberPosition BarTool
AboutMotorcycleMaintenance MaintenancePeriodTable
TechnicalDataofMainPerformance SymbolDescriptions
StandardTorqueValues
EngineNumberPosition
PhotoofCompleteVehicle:
FrameNumberPosition: EngineNumberPosition:
EngineNumber
FrameNumber

YG125-30B Maintenance Manual Overview
2
MaintenancePrecautions
1. Wheneverreassemblingafterbeingdisassembled,
replacenewwashers,sealingmembers,etc.
2. Whilefasteningboltsornuts,proceedindiagonal
crossingsequencetograduallyscrewdowntothe
requiredtorquefor2to3tries.
3. Afterbeingdisassembled,thepartsand
componentsshouldbecleanedbeforebeing
inspectedandmeasured
Tocleanthespareparts,useonlythecleaning
fluidthatisincombustibleorhashighignitionpoint.
Beforereassembling,applythespecified
lubricatingoiltotheslidingsurfaceofthepartsand
components.
Afterreassembling,checkwhetherallthespare
partsaremountedproperlybymeansofturning,
movingandoperatingthem.
4. Todisassembleandassembleamotorcycle,
specialservicetools(SST)andgeneral-purpose
toolsmustbeusedinaccordancewithrelevant
regulations.
5. Thespecifiedorequivalentlubricatinggrease(oil)
mustbeappliedtoorrefilledintothespecified
locations.
6. When2ormorepersonsarecarryingoutthe
operation,theyshallworkwitheachotherandpay
attentiontosafety.
7. Beforeoperating,alwaysremovethenegative(-)
endofthebatteryfirstandtakecaretopreventthe
wrenchorthelikefromtouchingtheframe.After
operating,reconfirmalltheconnections,fixings
andjunctions.Ifthebatteryisalreadyremoved,
connectthepositive(+)endfirst.

YG125-30B Maintenance Manual Overview
3
8. Incasethefuseisblown,checkforthecausesand,
afterbeingrepaired,replacecorrespondingfuse
asperthespecifiedcapacity.
9. Thecapsmustbesecurelyputontheterminals
aftertheoperationiscomplete
10.Whiledisassemblingaconnectorjointswithlock,
releasethelockbeforeproceedingwithoperation.
Whiledisassemblingaconnectorjoints,holdthe
connectorbodywithoutpullingthewireharness.
Beforeconnectingtheconnector,theterminalsshallbe
freefrombreakingorbending.Makesuretheterminals
arenottoolongorarefallingoff.
Theconnectorshallbefullyinsertedinplace.
Foraconnectorwithlock,confirmwhetherthelockis
completelyfixed.
Makesuretheharnessisnotfallingoff
Makesuretheplasticjacketoftheconnectorissecurely
coveringtheconnectorwithoutscalingoff.
11.Beforeconnectingaconnector,makesurethe
sleeveisnotbrokenandtheopeningofthe
intermediateterminalisnottoolarge
Thejointshallbefullyinsertedinplace.
Makesuretheplasticjacketishousingtheterminal
completely.Theopeningoftheplasticjacketshallnot
faceup.
12.Theharnessfixingstrapshallfirmlybuttonthe
specifiedpositionontheframe.
Confirmcapacity! Crackle

YG125-30B Maintenance Manual Overview
4
13.Theclampshallreliablybitethewireharness
Incaseofaweldedclamp,itshallnotbitethewire
harnesstowardstheweldmark
Thewireharnessshallbeclampedattheposition
withoutcontactingarotatingpartoraremovingelement.
Thewireharnessshallbeclampedattheposition
withoutcontactingapartthatgenerateshigh
temperature.
Thewireharnessshallbeclampedattheposition
withoutcontactingtheedgeorsharpcornersofthe
vehiclebody.
Thewireharnessshallbeincapableofpassingthrough
thepositioncontactingabolt,ascrewheadoranyfront
part.
Thewireharnessshallnotbeslackenedorbeforcibly
pulled.
Ifthewireharnesshastocontacttheedgeorsharp
cornerparts,thecontactingpartshallbeprotectedwith
hoseoradhesivetape.
Incaseofawireharnesswithgarland,itshallbereliably
harnessed.
Donotdamagethegarnishofthewireharness.
Oncethewireharnessisdamaged,repairitbycoiling
withplasticadhesivetape.
Whilemountingpartsandcomponents,donotpressthe
wireharness.
Donotmountwireharnesswithittwisted.
Donottouch!
Donotpull!
Payattentionnottopressit.

YG125-30B Maintenance Manual Overview
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14.Whenwiring,notewhenturningitleftwardsor
rightwardstothelimitposition,thewireharness
shallnotbetighteneduporslackened,andmake
surethereisnosignificantbending,pressing,
interveningofmarginalparts.
15.Whileusingthetesttable,operateaccordingtothe
maintenancemanualafterunderstandingthe
explanationsintheinstructionmanual.
16.Donotdroporthrowthepartsandcomponents.
17.Incaseofrustontheterminals,carryout
connectionoperationafterdisposingitwith
abrasivepaper,etc.
18.Donotforciblytwistorforcefullybendthecable.
Becauseadeformedordamagedcableisthe
causeofbadoperationanddamage.
Rustmustbe
eliminated!
Haveyoulearnedbyheartthemethod
ofapplication?Arethemeasurement
rangeandpolarityinaccordancewith
theinstructionmanual?

YG125-30B Maintenance Manual Overview
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TechnicalDataofMainPerformance
Item Data
Dimension & Weight
Length
Width
Height
Wheelbase
Min.groundclearance
Completevehicleweight
2050mm
830mm
1075mm
1360mm
200mm
Non-loadedweight:128kg,Curbweight:136kg,
Vehicle body
Frametype
Rakeangle
Frontsuspensiondevice
Rearsuspensiondevice
FrontTiresize
RearTiresize
Frontwheelpressure
Rearwheelpressure
Frontbrake
Rearbrake
Fueltankvolume
Fuelgrade
Cradletype
26
spring&hydrauliccompositedamping
spring&hydrauliccompositedamping
110/90-17
130/80-17
Normallyloaded:225kPa,
Normallyloaded:225kPa,
Singledisctype ModelΦ276
Singledisctype ModelΦ220
12L
93#

YG125-30B Maintenance Manual Overview
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Driving system
Clutch
Clutchoperatingsystem
Variablespeedgear
Primaryreductionratio
Transmissiongearratio
Finalreductionratio
Gearshiftingmode
Wetclutch,coilclutch,paperfrictionwafer
Manualmechanical
5-speedconstantmesh
3.35
Ⅰ3.077
Ⅱ1.789
Ⅲ1.304
Ⅳ1.091
V0.929
3.333
Leftfootoperatedtoandbacktype
Sequence: I－N－Ⅱ－Ⅲ－Ⅳ-V
Engine
Mode
Cylinderbore Stroke
Cylinderdisplacement
Compressionratio
Max.power
Max.torque
Valveclearance(cold)
Valvedrivinggear
Airfilter
Coolingmethod
Lubricationmethod
Engineoilgrade
Engineoilchargevolume
Engineoilfilterelement
Electricmotorstarting
Idlespeed
Netweightofengine
Single-cylinder forceair –cooling 4-strokeengine
52.4mm ×57.9mm
125cc
9.0:1
6.8kw/7500rpm
9N.m/6500rpm
IN: 0.06-0.08
EX: 0.06-0.08
Chaindrive
Oilpaperfilter
forceair-cooling
PleaseapplyShell10W/40-SFengineoilinsummerand10W/30-SFin
winte
1L
Oilpaperfilter
Electric/footstart
1500±150r/min
28.5±1kg

YG125-30B Maintenance Manual Overview
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Electrical system
Electricgenerator
Accumulatorcapacity
Powersupplysystem
Fusiblecutout
Sparkplug
Sparkpluggap
Ignitioncoiltype
Fuelsupplymode
Ignitionmode
Ignitionadvanceangle
Ignitiontiming
Frontlamp
Turnlamp
Stop/Rear-positionlamp
permanentmagnetDCmagneto
12V7A.h
DCpowersupply,andtheelectricgeneratorisonlyusedtorecharge
theaccumulator
15A/10A
CPR8EA-9
0.7-0.9mm
Openmagneticcircuit
Electronicallyinjection,ECUcontrol
EMS
EMS
EMS
12V/35W/35W
Front:12V10W Rear:12V10W
12V21W/5W
StandardTorqueValues
ENGINE
Item Quantity Threaddiameter
(mm) Torquevalue(N.m) Threadlocker
Cylinderheadcoverconnectingbolt 13 8 8～12
Cylinderbolt 410 40～50
2 6 8～12
Valveadjustingscrewnut 4 10 8～12
Timingdrivensprocketbolt 2 7 7～11
Rocker-armshaftcover 2 14 24～28
Magnetoflywheelfasteningnut 1 12 38～45 LOCTITE243
Clutchfasteningnut 1 18 114～126 LOCTITE243
Primarydrivinggearfasteningnut 1 18 143～157 LOCTITE243
Oildrainplug 1 12 28～32

YG125-30B Maintenance Manual Overview
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Crankshaft,main-shaftbearingbafflescrew 5 6 8～12 LOCTITE648
Stud 1 6 8～12
Stud 4 10 40～50
Exhaustvalvestudbolt 2 8 10～14 LOCTITE243
Statorconnectingbolt 3 6 8～12 LOCTITE648
Statorleadspressureplatebolt 2 6 8～12 LOCTITE648
SparkPlug 1 12 18～25
Pensionerplatefasteningbolt 1 6 7～10
Vehiclebody
Item Quantity Threaddiameter
(mm) Torquevalue
(N.m)
Threadlocker
Frontwheelspindle 1 14 50～60
Frontvibrationdamperplate 1 10 30～40
Realwheelspindlenut 1 16 60～90
Rearforkshaftnut 1 14 50～60
Enginehangingbolt 310 30～40
4 8 20～30
Steeringhandlesetbolt 4 8 20～30
Frontforkverticalpipecapnut 1 22 60～90
Lowerconnectionplatesetbolt 2 10 30～40
Upperconnectionplatesetbolt 2 6 8～12
Rearsprocketnut 6 8 20～30 LOCTITE243
Brakediscfasteningnut 8 8 20～30 LOCTITE243
Speedsignalpanelscrew 4 8 20～30 LOCTITE243
Frontbrakecaliperscrew 2 8 20～30 LOCTITE243
Inadditiontothetorquevaluesoftheimportantpartsaslistedabove,thetorquevaluesforotherstandard
fastenersareasfollow:
Nameanddimensions Torquevalue(N.m)
5mmbolt&nut 4.5 ～6
6mmbolt&nut 8 ～12
8mmbolt&nut 18 ～25
10mmbolt&nut 30 ～40
12mmbolt&nut 50 ～60
5mmScrew 3.5 ～5
6mmScrew 7 ～11
6mmspoolbolt&nut 10 ～14
8mmspoolbolt&nut 20 ～30
10mmspoolbolt&nut 30 ～40
BarTool

YG125-30B Maintenance Manual Overview
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Motorizedgun:specialpowertoolformantling/
dismantlingboltandnut
Pawlsocket: formantling/dismantlingoilfilteringelement
nutandclutchnut
AandBboltsocket:formantling/dismantlingAandB
boltandexhaustmufflerbolt
Adaptor:electricspecialtoolforcross,hexagonguntip
Valveadjustingsocket:forvalveclearanceadjustment
Socket:formantling/dismantlingnutsandbolts
Cuttingplier,Nipperplier,expansionplier:formantling/
dismantlingflexibleretainer
T-socketwrench
Magneticgeneratorrotorpuller:fordismantling
magneticgeneratorrotor
Rubberhanner,Ironhammer,Copperhammer
Feelergauge:tomeasuretheclearanceofpiston,
cylinder,valve,etc.
Micrometer: tomeasurethedimensionsofpiston,piston
pin,etc.

YG125-30B Maintenance Manual Overview
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Dialgauge:tomeasurethewheelbouncing,cylinder
innerdiameter,etc.
Cylinderbarometer: tomeasurethecylinderpressure
Wrench:measuretightenessofadbolt Verniacaliper:measuresizeofrearwheelhubinternal
diameter
Tirebarometer: tomeasurethetirepressure
MaintenancePeriodTable
Maintenancetimes
MaintenanceItems
Period
Odometerkm(Remark2)
1000
km
4,000
km
8,000
km
12,000
km Remarks
*Fuelsystempassage I I I
*Throttleoperatingsystem I I I I
*Throttlevalvebody I I I I
Airfilterelement Remark1 C C Replaceevery12,000kmdriving
SparkPlug I I Replaceevery12000kmdriving
Enginelubricantoil Foramotorcycle,changeevery1000km,andthenchangeitevery
2000kmdriving
Oilfilter R Replaceevery12,000kmdriving
*Tensioner Remark3 I I I I
bothintakeandexhaust Remark3 I Checkevery4,000kmdriving
Clutch I I I I
*Drivingchain ProceedwithIandLforevery500kmdriving

YG125-30B Maintenance Manual Overview
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** Frontandrearbrakesystem I I I I
** BrakePad I I I I
** Brakefluid Changeevery2years
*Frontandrearbrakelamp
switch I I I I
*Accumulator Monthly I I I I
* Suspensionsystem I I I I
*Nutandboltfastening I I I I
** Wheel&tire I I I I
** Steeringcolumnbearing I I I I
** Steeringbackstaycable Inspectevery5000kmdrivingandreplaceevery10000kmdriving
Maintenanceshallbecarriedouttothemotorcycleinaspecifiedperiod.Themeaningsofvarioussymbolsinthelistare
asfollows: I:Carryoutinspection,cleaning,adjustment,lubricationorreplacement.
C: Cleaning. R: Replacement. A: Adjustment. L: Lubrication.
*ThisitemissubjecttomaintenancebypersonsfromYINGANGTECNOLOGYServiceStation.Iftheuserhas
specialservicetools,maintenanceaccessoriesormaintenanceability,itcanrepairitbyitself.
** Toensuresafety,thisitemisonlysubjecttomaintenancebypersonsfromYINGANGTECNOLOGYService
Station.
Remarks:
①Whiledrivinginadustyarea,itshallbecleanedmoreoften.
②Whentheodometerreadsmorethanthegivenmaximumvalue,itsmaintenanceperiodshallstillrepeatasperthe
mileintervalasstipulatedinthetable.
③Toensuresafety,theadjustmentoftimingchainandvalveclearanceshallonlybecarriedoutbypersonsfrom
YINGANGTECNOLOGYServiceStation.
SymbolDescriptions
Meaningsofvarioussymbolsinthismanual:

YG125-30B Maintenance Manual Overview
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Eachtimereassembledafterbeingremovedanddisassembled,itmustbereplacedwithanew
one.
Usespecialservicetools(SST)
Usegeneral-purposetools.
Tighteningtorqueof50N.m.
Usesuggestedengineoil.
Usethemixturesofengineoilandmolybdenumdisulfide
Usethreadlocker.
Usesealant.
Uselithiumbasegrease.
1
Measurestobepromptedduringoperating,inspectingand
maintaining.
2
Specialinstructionsordisposalmeasuresgiventoprevent
motorcyclefrombeingdamaged.
3
Specialinstructionsormeasuresgiventoavoidserious
damagesorpersonalinjuries.
Explanation
NOTICE:
WARNING:

YG125-30B MaintenanceManual Lubricationsystem
14
2 Lubricationsystem
Maintenancenotice Inspectionoflubricatingoil
Troubleshooting Replacementoflubricatingoil
LubricatingPositionofCompleteVehicle CleaningofLubricatingOilStrainer
LubricationofControlLines CleaningandReplacementofLubricatingOilFilter
EngineLubricationSystemDiagram OilPump
Maintenancenotice
Thissectionintroducestheinspectionandreplacementmethodofenginelubricatingoilaswellasthecleaningmethodof
lubricatingoilstrainerandlubricatingoilfilter.Italsointroducesvariouslubricatingpositionsofthecompletevehicleofthis
model.
Asanimportantfactorthatinfluencestheengine’sperformanceandlifespan,thelubricatingoilmustbeselectedasper
regulations;ordinaryengineoil,gearoil,vegetableoil,etc.arenotallowedtobeusedinsteadofit.Thisenginewasfilled
withgasolineengineoilof10W/40EGgradewhenleavingfactoryforsale.Ifyouwanttouseotherlubricatingoil,its
qualityscalemustreachGradeSG,anditsviscosityshallbeselectedaccordingtotheaccompanyingdiagramdepending
uponregionandairtemperaturechanges.Whilereplacinglubricatingoil,fullydischargetheoriginallubricatingoilinthe
crankcaseandcleanitupwithwashingkerosene,andthenrefillfreshlubricatingoilasperregulations.
Thelubricatingoilinsidetheenginemustbefullydischargedbeforeinspectionandcleaning.
Technicalspecifications:Lubricatingoilchargevolume:1L
Oilpumpflowrate:8L/min(whenenginespeedisat4000rpm).
Tighteningtorqueofoildrainplug:28-32N.m
Selectingviscosityaspertemperatureconditions
Lowtemperatureproperty �Fueleconomicalefficiency �Lubricatingpropertyunderhightemperature Hightemperatureproperty
�Lowtemperaturestarting
property �Noise reduction property under high temperature
WARNING:
Repeatedlycontactingtheenginelubricatingoil
foralongperiodmaycauseskincancer.
Althoughsuchpossibilityissmallwhenyou
dealwithusedenginesoileveryday,Care
mustbetakentofullycleanseyourhandswith
soapandwaterafterdealingwiththeused
engineoil.Childrenarestrictlyprohibitedfrom
gettingneartoit.

YG125-30B MaintenanceManual Lubricationsystem
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Troubleshooting
●Lubricatingoilcontaminated
1. Failtoreplacelubricatingoilaccordingtothe
maintenanceperiodtable;
2. Thepouringorificethreadisdamagedthuscausing
poorseal;
3. Thepistonringisworn.
●Lubricatingoilpressurelow
1. Theoillevelistoolow;
2. Oilthrough,orificeportoroilstrainerisclogged;
3. Oilpumpsfailure.
●Lubricatingoilconsumestoofast
1. Thereisleakagewiththeengine;
2. Thepistonringisworn.
3. Theinlet/exhaustvalveguideisworn;
4. Theoilshieldiswornordamaged.
LubricatingPositionofCompleteVehicle
Amongthepositionsshownintheabovediagram,besidesapplyingdedicatedlubricatingoilforchain to
thedrivingchain,applylithiumbasegreasetoallotherpositions.
Alllubricatingoilsnotspecifiedforuseinthismanualshallbeordinarycommonlubricatingoil.
Allslidingsurfacesandcablesnotshowninthisdiagramshallbecoatedwithlubricatingoilorlubricatinggrease.
LubricationofControlLines
Regularlubricationshallbecarriedouttotheclutchcontrolline,throttlecontrollineandsteeringcable.Todothis,remove
theupperjoiningpartsofallcontrollines,sufficientlylubricateandmaintaintheirhoistingcablesandallpointsofsupport
withlithiumbasegrease.
Frontwheelbearing
Rearwheelbearing
Engine
lower
hanging
bolt
Rearforkshaftlever
Sidestandshaft
Drivingchain
Upper/lowerretainersofverticalpipe

YG125-30B MaintenanceManual Lubricationsystem
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EngineLubricationSystemDiagram
Crankshaftoil
through
Spindle
oil
through
Countershaftoilthrough
Camshaftoilthrough
Cylinderheadoilthrough
Cylinderoilthrough
Oilfilter
Oilpump
Oilstrainer

YG125-30B MaintenanceManual Lubricationsystem
17
Replacementoflubricatingoil
Whilereplacinglubricatingoil,itshallbecarriedoutbeforetheenginehascooleddown.Thiswillensurequickand
completedischargeoftheengineoilinsidethecrankcase.
Whenreplacing,unscrewtheoildrainpluganddischargethewasteengineoil,andthencleantheoildrainplug,engineoil
strainer,engineoilfilter,etc.Finally,inserttheoildrainplug.Unscrewtheoilfilterplugandslowlyrefill1.8Lnewengineoil
ofthespecifiedtrademarkintothecrankcase,theninserttheoilfilterplug.
Leftcrankcasebodyoilthrough Cylinderblock,cylinderhead,camshaftbearingseatanda
camshaftoilthrough
Wasteengineoilflowintotheoilcollector
Lubricatingoildraining

YG125-30B MaintenanceManual Lubricationsystem
18
CAUTION
Applicationofengineoilofpoorqualitywillhaveanimpactonthefunctionalperformanceandlifespanofthe
motorcycleengine.
CleaningofLubricatingOilStrainer
Itshallbecarriedoutwhilereplacinglubricatingoil.
Whilecleaning,youshouldunscrewtheoildrainplugtodrainthewasteengineoil,andflushthestrainerwithcleaning
agent;placethemotorcyclesidedowntofacilitatecleaningasrequired.Theninserttheoildrainplug,andproceedwith
theremainingstepsaccordingtothemethodof “ReplacementofLubricatingOil".
CleaningandReplacementofLubricatingOilFilter
Removetheengineoilfiltercovertodetachtheengineoilfilterelement,cleanthefiltercoverandfilterelementwith
cleaningagent,andthenmountthecleanengineoilelement.Replacewithanewoneasrequired.
CheckfordamageoftheengineoilfiltercoveranditsO-shapedsealingring;replacewithanewoneasrequired.
Mounttheengineoilfiltercoverandscrewupthebolttothespecifiedtorque.
Notice
Beforethecrankcaseisrefilledwithfreshengineoil,theengineoilfiltermustbecleaned.
Flushthestrainerwithcleaningagent
Cleaning
Removeoilfilter ReplacementofFilter
CleaningofStrainer