ClassicMotorcycleMechanicsJune2020

(Jacob Rumans) #1

I


nmylifeIhavealways
consideredtwo-strokesto
betroubleandinmy
experiencethemorepots,the
moretrouble;ergotriple
troubledeliveredbythepurplepestilence!
Thelastjobtodointheenginebuild
framewastorefitthecheckvalvesatthe
bottomofthecrankcases.Thesewerean
ideaKawasakiHeavyIndustriesdreamed
upin 1974 fortheH 2 Bonwardsinan
efforttodosomethingusefulwithanyoil
buildingupinthebottomofthecrankcase
whenthebikehasbeenidlingorslow
running,andtoattempttoreducethe
noxioussmokecloudfromtheexhausts
whenoneisbackonthepower.Whenthe
enginerevsupagaincrankcasepressure
increases,forcingtheoilintodrillingsat
thebottom,whichthenfeedsoilintothe
one-waycheckvalveandthenintothe
left-handmainbearingofeachindividual
pot.Themicapetalone-wayvalveandthe

constantlychangingpressuresinthe
crankcaseeffectivelymakethisascavenge
pump.Thishastheeffectofincreasing
lubricationonthebearingandthenmakes
iteasierforusedtwo-strokeoiltojointhe
swirlingair/fuelmixtureheadedupstairsto
thecombustionchamber.
ReadingthebusyforumontheTriples
Club,wheretherearesomeseriously
knowledgeablefolk,itseemsthatthe
generalconsensusisthatthesevalves
bringlittletothepartyandmanyowners
deemitbesttoblockthemup.Giventhe
originalityofmybikeIwantthemback
wheretheyshouldbe,giventhatanything
non-standardwouldnegativelyaffectthe
monetaryvalueofthePurplePain.
Havinghadthemre-platedinbrightzinc
plate,astheywerewhenIboughtthe
bike,Ihavenowdiscoveredthatthey
shouldhavehadayellow/goldpassivate!I
tookplentyofpicsasIdisassembledthem
formyarticles,soIcheckedbackwith

themtomakerebuildingthemapieceof
urine.Forthosenotwritingabouttheir
endeavours,canIsuggestyouusea
smartphonetoarchivethestrip;thoughif
itendsupasdisgustinglyfilthyasmy
trustyDSLRyouwillneedtocleanit
regularly!Ire-usedthegasketswhichwere
ingoodconditionwithasmearofWellseal.
BecauseIfounditslightlytricky
extricatingthemotorfromtheframeinits
entirety,withoutchippingpaintonthe
downtubes,Idecidedtomakelifeeasier
bynotputtingontheoutercasingsor
top-endbeforereplacingtheengineunit,
particularlyasIdidn’thaveasparepairof
skilledhandsavailable.Havingnailedthe
clutchbackintoplace,itwasnowtimeto
re-homethelump.Iprotectedthepainted
framepartswithworkshoptowelsandthen
slidabitofgashMDFoverthebottom
framerails.Ibuiltupaplatformunderthe
motorintheenginebuildingframewith
woodenblockssothatwhenIremovedthe

Ralphhuffsandhepuffsasheleversthetriplestrokerbackintoitsnaturalhome



  • butwhat’sthis?


Kawasaki H2C part 6 W


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Seal the deal...


88 /classicmotorcyclemechanics


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