CSC RX3 - Page 47

CSCRX3ServiceManual
www.CSCMotorcycles.com
46
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effectofreducingthevalvegap(i.e.,theclearancebuiltintothevalvetraintoaccountforthethermal
expansionastheenginewarmsup).
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Whathappensisthatasthiswearoccurs,thevalveactuallymoveshigherintothecylinderheadandthe
valvegapdecreases.Ifthiswear
goesbeyondacceptablelimitswithoutadjustingthevalves,thevalve
gapgrowssmallerandsmaller.Ultimately,thiswearwillresultinthevalvebeingheldofftheseatwhen
combustionoccurs.Whenthisconditionexists,hotburninggasesescapearoundthevalvesealing
area.Ultimately,theseburninggaseswilldestroythe
valveandtheseat.That’swhathappenswhena
valve“burns.”
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Thisaboveundesirableconditionisavoidedbyadjustingthevalves.Thiskeepsgapsinthevalvetrain
withinanacceptablerangeoverthelifeofanengine.Asthevalveandthevalveseatwear,valvewe
keepeverything
adjustedsothatwhentheengineisatoperatingtemperatureitstillformsagoodseal
aroundthevalveseat.
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Differentenginesusedifferentapproachesforadjustingthevalves.TheCSCRX3usesthebest
approachforeasymaintenanceandhighperformance:Itusesathreadedadjustorshaftwithalock
nut
tosetandlockthevalvegap.Theseadjustorsarelocatedintheendsoftherockerarmsthatinterface
directlywiththevalvestem.Theseareshowninthesketchabove,andinthephotosthatfollow.
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TheCSCRX3valveadjustmentprocessconsistsofthefollowingsteps:
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1. Wegainaccesstothevalverockerarmsandtheiradjustmentscrews.
2. Wepositiontheenginetobeatapointinitsrotation suchthattherockerarmisonthecam’s
basecircle.Thismeansthecamisnotactuatingtherockerarm.Wewantthe
enginetohave
thepistonattopdeadcenteronthecompressionstroke,whichmeansthevalvesshouldbe
closed(whichisanotherwayofsayingtherockerarmisonthecam’sbasecircle).
3. Withtheengineinthisposition,wewanttoloosenthethreadedadjustorlocknuts,
wewantto
setthevalvegapstothespecified gapof0.04mmto0.08mm,andwewanttotightenthelock
nutstolockthethreadedadjustorsatthisgap.
4. Whenwe’vecompletedtheabove,wewanttoputeverythingbacktogether.
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Whenyouadjustthevalves,
youhavetostartwithacoldengine.LetyourRX3coolcompletely.
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Removetherearseatwiththekeylock,thefrontseatwithitstwo8mmbolts,allofthebodywork
aroundthefueltanks,andthefueltank.Ifyoudothiswhenthefueltankislow
onfuel,itwillmake
handlingthefueltankeasier.
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Makesureyoudon’tspillanyfuel,andmakesureyouputthefueltankinalocationwherethereareno
ignitionsources.
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Takecarenottoscratchanyofthebodywork.
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