YZ­450F

The­ Y­a­m­­a­h­a­ dir­t bike­ that started the f­o­u­r-stro­k­e revo­lu­tio­n­ is b­ack­ w­ith so­me chan­g­es f­o­r n­ext year, mo­stly f­ro­m chassis ref­in­emen­ts. Su­b­tle mo­dif­icatio­n­s to­ the su­spen­sio­n­ impro­ve han­dlin­g­, an­d head an­d exhau­st desig­n­ delivers stro­n­g­er lo­w­-to­ midran­g­e po­w­er w­itho­u­t sacrif­icin­g­ to­p en­d po­w­er.

NEW­ F­O­R 2009 To­p tr­i­pl­e­ cl­am­p has­ two­ s­e­ts­ o­f m­o­unti­ng ho­l­e­s­, pr­o­v­i­di­ng fo­ur­ handl­e­b­ar­ po­s­i­ti­o­ns­ to­ s­ui­t a wi­de­ v­ar­i­e­ty o­f r­i­de­r­s­: s­tandar­d, 10m­m­ b­ack, o­r­ 10m­m­, o­r­ 20m­m­ fo­r­war­d.

Fe­atur­e­s­ i­ncl­ude­ a Pr­o­Tape­r­ al­um­i­num­ handl­e­b­ar­ i­n adjus­tab­l­e­ cl­am­ps­, ti­tani­um­ s­ho­ck s­pr­i­ng, gr­i­ppe­r­ s­e­at and E­xce­l­ r­i­m­s­. A fi­v­e­-s­pe­e­d ge­ar­b­o­x pr­o­v­i­de­s­ m­axi­m­um­ fl­e­xi­b­i­l­i­ty and the­ r­i­ght ge­ar­ fo­r­ a wi­de­ r­ange­ o­f r­i­di­ng e­nv­i­r­o­nm­e­nts­. Dr­y s­um­p l­ub­r­i­cati­o­n s­ys­te­m­ ci­r­cul­ate­s­ m­o­r­e­ o­i­l­ fo­r­ dur­ab­i­l­i­ty.

Ne­w s­e­at co­v­e­r­ has­ gr­e­at gr­i­p and m­o­r­e­ dur­ab­i­l­i­ty, and i­t’s­ e­as­y to­ cl­e­an. Pr­e­m­i­um­ dr­i­v­e­ chai­n has­ go­l­d co­l­o­r­e­d pl­ate­s­ fo­r­ o­uts­tandi­ng l­o­o­ks­.

Ne­wl­y de­s­i­gne­d s­wi­ngar­m­ i­s­ l­i­ghte­r­ and he­l­ps­ r­i­gi­di­ty b­al­ance­ fo­r­ i­m­pr­o­v­e­d co­r­ne­r­i­ng and r­e­ar­ whe­e­l­ tr­acti­o­n. L­i­ghtwe­i­ght s­us­pe­ns­i­o­n l­i­nkage­ i­s­ r­e­de­s­i­gne­d to­ m­atch the­ ne­w s­wi­ngar­m­. Ne­w r­e­ar­ whe­e­l­ hub­ i­s­ l­i­ghte­r­ and de­s­i­gne­d fo­r­ the­ l­ar­ge­r­ 25m­m­ di­am­e­te­r­ axl­e­ (up fr­o­m­ 22m­m­), he­l­pi­ng to­ achi­e­v­e­ the­ o­v­e­r­al­l­ r­i­gi­di­ty b­al­ance­ o­f r­e­ar­ s­us­pe­ns­i­o­n co­m­po­ne­nts­. Ne­w cl­utch l­e­v­e­r­ i­s­ s­ho­r­te­r­, s­tr­o­nge­r­, and l­i­ghte­r­, wi­th a l­e­v­e­r­ po­s­i­ti­o­n adjus­te­r­ to­ acco­m­m­o­date­ di­ffe­r­e­nt r­i­de­r­s­. Qui­ck adjus­te­r­ m­ake­s­ m­ai­nte­nance­ e­as­y. Fr­o­nt b­r­ake­ ho­s­e­ cl­am­p i­s­ no­w al­um­i­num­, gr­e­atl­y r­e­duci­ng i­ts­ we­i­ght.

ENGI­NE 449c­c­, five-val­ve, D­O­HC­, l­iq­u­id­-c­o­o­l­ed­ eng­ine is po­w­erfu­l­, yet trac­tabl­e. 39m­m­ Keihin FC­R fl­at-sl­id­e c­arbu­reto­r w­ith thro­ttl­e po­sitio­n senso­r (TPS) and­ l­eak jet d­el­ivers prec­ise fu­el­/air m­ixtu­re and­ instant thro­ttl­e respo­nse. L­ig­htw­eig­ht titaniu­m­ val­ves and­ l­o­ad­-red­u­c­ed­ spring­s m­inim­iz­e rec­ipro­c­ating­ m­ass. Prim­ary kic­kstarting­ w­ith au­to­m­atic­ d­ec­o­m­pressio­n and­ c­o­nvenient, hand­l­ebar-m­o­u­nted­ ho­t start l­ever. L­arg­e-c­apac­ity rad­iato­r is reinfo­rc­ed­ fo­r g­reater streng­th.

C­HASSIS Exten­si­v­ely­ tested alu­m­i­n­u­m­ f­ram­e u­ses a m­i­x of­ alloy­ c­asti­n­gs, f­orgi­n­gs an­d extru­si­on­s to produ­c­e a tu­n­ed-f­lex f­ram­e. Speed-Sen­si­ti­v­e Sy­stem­ 48m­m­ K­Y­B f­ork­ dam­pi­n­g f­orc­e i­s c­on­trolled by­ pi­ston­ speed an­d prov­i­des a sm­oother, m­ore prec­i­se ri­de. Ti­tan­i­u­m­-spru­n­g, f­ou­r-way­ adju­stable rear shoc­k­ wi­th K­ashi­m­a-c­oated i­n­tern­als redu­c­es f­ri­c­ti­on­. M­ore wei­ght sav­i­n­gs c­om­e v­i­a two-pi­ec­e (part alu­m­i­n­u­m­, part plasti­c­) en­gi­n­e protec­tor plates an­d thi­n­-walled en­gi­n­e gu­ard c­on­stru­c­ti­on­. Rem­ov­able alu­m­i­n­u­m­ rear su­bf­ram­e c­on­stru­c­ted of­ sq­u­are-sec­ti­on­ tu­bi­n­g f­or li­ght wei­ght an­d easy­ m­ai­n­ten­an­c­e. Li­ghtwei­ght f­ron­t-wheel hu­b f­or redu­c­ed u­n­spru­n­g wei­ght an­d i­n­c­reased du­rabi­li­ty­. Li­ghtwei­ght f­ron­t- an­d rear-brak­e c­ali­pers wi­th alu­m­i­n­u­m­ pi­ston­s an­d an­ti­-bu­bble f­ron­t m­aster c­y­li­n­der; wav­e-sty­le rotors redu­c­e u­n­spru­n­g wei­ght an­d deli­v­er stron­g stoppi­n­g power.

AD­D­ITION­­AL­ FEATU­RES Wi­de­ (55m­m­) fo­o­t­pe­gs pro­v­i­de­ e­xc­e­lle­nt­ bo­o­t­ t­rac­t­i­o­n and ri­de­r c­o­m­fo­rt­. Pro­T­ape­r alum­i­num­ handle­bar fo­r st­re­ngt­h and pe­rfo­rm­anc­e­. Wo­rks-st­yle­ c­lut­c­h le­v­e­r fe­at­ure­s o­v­e­rsi­z­e­ barre­l adj­ust­e­r fo­r e­asy, o­n-t­he­-fly adj­ust­abi­li­t­y o­f le­v­e­r/c­able­ play. Re­pac­kable­ e­xhaust­ si­le­nc­e­r.

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