Yamaha QT 50F User manual

NOTICE

ThismanualhasbeenwrittenbyYamahaMotorCompanyforuseby

AuthorizedYamahaDealersandtheirqualifiedmechanics.Inlightofthis

purposeithasbeenassumedthatcertainbasicmechanicalpreceptsand

proceduresinherenttoourproductarealreadyknownandunderstoodby

thereader.Thisservicemanualhasbeenwrittentoacquaintthemechanic

withcommondisassembly,inspection,reassembly,maintenance,and

troubleshootingproceduresassociatedwiththismachine.

TheResearch,Engineering,andServiceDepartmentofYamahaare

con-

tinuallystrivingtofurtherimproveallmodelsmanufacturedbythecom-

pany.Modificationsarethereforeinevitableandsignificantchangesin

specificationsorprocedureswillbeforwardedtoallAuthorizedYamaha

Dealersand

will,

whereapplicable,appearinfutureeditionsofthismanual.

Particularlyimportantinformationis

distinguished

inthismanualbythe

followingnotations:

NOTE:

A NOTEprovideskeyinformationtomakeprocedures

easierorclearer.

CAUTION:

A CAUTIONindicatesspecialproceduresthatmustbe

followedtoavoiddamagetothemotorcycle.

WARNING:A WARNINGindicatesspecialproceduresthatmustbe

followedtoavoidinjurytoa motorcycleoperatororper-

soninspectingorrepairingthemotorcycle.

QT50F

SERVICEMANUAL

1stEdition-March1979

2ndPrinting,November

1980

OCL

3rdPrinting,July

1981

OCL

ALLRIGHTSRESERVEDBY

YAMAHAMOTORCORPORATION,

U.S.A.

PRINTEDIN

U.S.A.

LIT-11616-01-31

SECTIONINDEX

GENERALINFORMATION

PERIODICINSPECTIONAND

ADJUSTMENTS

ENGINEOVERHAUL

CARBURETlON

CHASSIS

ELECTRICAL

'vVys

APPENDICES

•-

«*i

«ajL_.„

. ,.

-'iH

i' '•

CHAPTER

1.GENERALINFORMATION

1-1.

MACHINEIDENTIFICATION1-2

1-2.SPECIALTOOLS1-2

<•)•

CHAPTER1.GENERALINFORMATION

1-1.

MACHINEIDENTIFICATION

The

fr&me

serialnumberislocatedonthe

frontslideoftheheadpipeassembly.The

firstthreedigitsidentifythemodel.Thisis

followedbya dash.Theremainingdigits

identify:theproductionnumberoftheunit.

POCKET

TESTER'

ToolNo.90890-03096

FLYWHEELHOLDINGTOOL

Tool

No.90890-01235

Theengineserialnumberislocatedona

raisedbossonthelowerleftsideofthe

engine.Engineidentificationfollowsthe

samecodeasframeidentification.

Engineserialnumber

•J%

I®.

-a

.sB

wmmB^LM

ELECTROTESTER

Tool

No.90890-03021

DIALGAUGE

ToolNo.

90890-03110

FLYWHEELPULLER

ToolNo.

90890-01189

1-2

CRANKICASE

SEPARATIONTOOL

Tool,No.

90890-01135

CRANK

Tool

Nci

INSTALLERPOT

90890-01274

ADAPTER

CRANKINSTALLERBOLT

Tool

No!,

90890-01278(M12)

EXHAU

RINGandSTEERINGNUTWRENCH

Tool

No.

90890-01268

Additional

ToolsandSupplies

Thicknessgauge

set

Torque

wrench

3.Tirepressuregauge

Fluidmeasuringcup

5.Micrometer

6.Verniercaliper

7.Cylindergauge

8.Magneticstand

10.

11.

12.

13.

14.

15.

BOLT

ToolNo.90890-01305

CRANKINSTALLERBOLT

ToolNo.90890-01275

HEXAGONWRENCH

Toll

No.

90890-01306

(25)

90890-01307(22)

Greasegun

Yamalube

4-cycle

oil

Yamalube

2-cycle

oil

Wheelbearinggrease

YamahabondNo.4

YamahaChainandCableLube

Lithiumbasewheelbearinggrease

(Ex.

SHELL

LETHINAXA)

1-3

CHAPTER2.

PERIODICINSPECTIONAND

ADJUSTMENTS

2-1.

2-2.

2-3.

2-4.

2-5.

INTRODUCTION2-2

MAINTENANCEINTERVALSCHARTS2-2

A.MaintenanceIntervals2-2

B.LubricationIntervals2-3

ENGINE2-3

A.Carburetor2-3

B.AirCleaner2-4

C.AutolubePump2-4

D.EngineandTransmissionOil2-5

E.CylinderHead2-6

CHASSIS2-6

Brake

andWheel(FrontRear)2-6

B.SteeringandSuspension2-7

ELECTRICAL2-8

A.IgnitionTiming2-8

B.SparkPlug2-8

C.Battery2-9

D.HeadlightBeamAdjustment

2-10

CHAPTER2.

PERIODICINSPECTIONANDADJUSTMENTS

2-1.

INTRODUCTION

Thischapterincludesallinformationnecessarytoperformrecommended

inspectionandadjustment.Thesepreventivemaintenanceprocedures,if

followed,

willinsuremorereliablevehicleoperationanda longerservice

life.

Theneedforcostlyoverhaulworkwillbegreatlyreduced.Thisinfor-

mationappliesnotonlytovehiclesalreadyinservice,butalsotonew

vehiclesthatarebeingpreparedforsale.Anyservicetechnicianperform-

ingpreparationworkshouldbefamiliarwiththisentirechapter.

2-2.

MAINTENANCEINTERVALSCHARTS

Thefollowingchartsshouldbeconsideredstrictlyasa guidetogeneral

maintenanceandlubricationintervals.Youmusttakeintoconsideration

thatweather,terrain,geographicallocation,anda varietyofindividual

uses.

Thistimescheduleshouldbealteredtomatchindividualowners'

requirements.Forexample,ifthemotorcycleiscontinuallyoperatedinan

areaofhighhumidity,thenallpartsmustbelubricatedmuchmore

fre-

quentlythatshownonthecharttoavoiddamagecausedbywatertometal

parts.

A.Mainter

cioj

Cylinderhead

Sparkplug

Airfilter

Carburetor

Autolubepurr

*Brakesystem

*Wheelsandt

*Suspensions

Fuelpetcock

•Battery

*Lights/Signal

ance

Intervals

tern

/Exhaustsystem

(complete)

res

stem

Fittings/Fastehers

Remarks

Decarbonize

Inspect/Cleaningorreplaceasrequired

Wet

type-Must

bewashedanddampedwith

Yamalube

2-cycle

OilorSAE20motoroil

Checkoperation/Fittings

Clean/Refit/Adjust

Check/Adjust/Airbleeding

Check/Adjustas

required-Repair

asrequired

Checkpressure/Wear/Balance/Runout

Check

operation/Repair

asrequired

Clean/Flushtankasrequired

Top-up/Checkspecificgravityandbreather

pipe

Checkoperation/Replaceasrequired

Tightenbeforeeachtrip

and/or...

•

Initial

month

months

Unit:

(mi)

Thereafterevery

months

year

*Indicatespre-operation

checkitems.

2-2

B.LubricationIntervals

Unit:km(mi)

Item

•Transmissionoil

*Conrolandmete

cables

Throttlegrip

an<j

housing

Brakelever,

Brakecamshaft

Steeringbearing

Speedometer

housing

Wheelbearings

Middleandfinal

gear

*Indicatespre-opera

tionchec

Remarks

Replace/Warmengine

beforedraining

Applythoroughly

Applylightly

Inspectthoroughly/Pack

moderately

Inspectthoroughly/Pack

moderately

Donotover-pack

yearlyor...

Seepage5-7torepack

grease

kitems.

Type

Yamalube

4-cycle

OilorSAE

10W/30

type"SE"motoroil

SAE10W/30

motoroil

Lithiumbasegrease

Medium-weightwheelbearing

grease

Lithiumbasegrease

Medium-weightwheelbearing

grease

Lithiumbasewheelbearinggrease

(EX.

SHELLLETHINAXA)

Initial

month

months

Check

months

Check

Thereafterevery

months

year

years

2-3.

ENGIN

Carburetcir

Pilotairscrew

Turnairadjustingscrewuntilitlightly

seats,

thenbackitouttospecification.

This

adjustment

canbemadewith

enginestopped.

Airscrew(Turnsout):1-3/4[1-1/2]

[]:AfterengineserialNo.

3L5-702401

Startthe

bngine

andletitwarmup.

3.Throttle

stop

screw

Turnthrottlestopscrewinoroutto

Pilotairscrew

Throttlestopscrew

achieve

specified

Idlingspeed

mooth

engineoperation

die

speed. at

1,700

r/min

Throttlecable

a.Throttlecable2.

Loosencableadjusterlocknut(attop

ofcarburetor)andturncableadjuster

untilspecifiedfreeplayisobtained.

Retightenlocknut.

NOTE:

Thepilotair

knd

throttlestopscrewsare

separateadjustmentsbuttheymustbe

adjustedatthesametimetoachieve

opti-

mum

operating

conditionatengineidle

speeds.

Freeplay:

1.0

mm(0.04in)

Adjuster2.

Lock

nut

2-3

;

III

;

*••'•'-

'•';

ft?

•_•:'

b.Throttle

cable2

directioh

cable1

After

engine

idlespeedandthrottle

aresetcheckplayintuning

ofthrottlegrip.Theplay

should

tie

3 mm(0.08

0.12in)

atgripflange.Loosenthelocknutand

turnthewireadjustertomakethe

necessaryadjustment.Afteradjusting,

besure

tightenthelocknutproperly.

Adjuster

B.AirClean

Remove

element

theaircleanercasecapand

assembly.

Wash

the

elementgently,butthorough-

ly,in

solvent.

Squeezeexcesssolventoutofelement

anddry.

Poura

small

quantityof20W.motoroil

onto

cleelner

elementandworkthor-

oughlyintotheporousfoammaterial.

Element

ihust

bedampwithoilbutnot

dripping.

5.Re-installtheelementassembly,case

coverandseat.

NOTE:

Eachtimecleanerelementmaintenanceis

performed,

checktheairinlettothecleaner

caseofobstructions.Checktheaircleaner

jointrubbertothecarburetorandmanifold

fittingsforanair-tight

seal.

Tightenallfit-

tingsthroughlytoavoidthepossibilityofun-

filteredairenteringtheengine.

r-CAUTION:

Neveroperatetheenginewiththeair

cleanerelementremoved.

Thiswillallow

unfiltered

airtoenter,

causingrapidwearandpossibleengine

damage.Additionally,operationwith-

outthecleanerelementwillaffectcar-

buretorjettingwithsubsequentpoor

performanceandpossibleengineover-

heating.

C.AutolubePump

Airbleeding

Tobleedtheoilpump,firstremovethe

bleedscrew.Startengineandrunat

idlingspeed.Thenpulltheoilpump

wireasmuchaspossible,andcontinue

toruntheengineuntilallairbubbles

disappearfromtheoilflowingoutfrom

thebleederhole.

Reinstallbleedscrew.

'.'''

zs\

\S4:S> J

'-"*-.

'r'i

',;-!

1J";i

i',

>•

: .-

lift

[

is'S

ifl

2-4

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