Cycle News is a weekly magazine that covers all aspects of motorcycling including Supercross, Motocross and MotoGP as well as new motorcycles
Issue link: https://magazine.cyclenews.com/i/125455
• • • TOP -Righ t outer ca se cutaway re peals ce n t ri f ug u ! oil filte r O il clld oi cran k s haft. primn ri, aeur clrit'e se t HI' be f u'een cra nksh u] t ami clu tc h IlO llSillg , Cent ra l oil filler cup s i m plifie s s e n -ic e; t1 l1 e sh ot supplies en gi ne , g ('(I,.1I O;f , cl utch. AilOl'E - Stnrt e r cln tch. wi th s p ri llg loaded bea r i np» th at sr!» flallg e Oil t he e llg ille s hn] ! et a rt er ep rocke t , A l ter it s peed » Up . cl ut ch rel ea ses [I ri p on t he sprock et w hich free-w h eels a ll s haft , • h ea d. Th is lincr is s p ig nt tr«] a t th e s pa rk plug' ho le s o th a t it a lso embra ces th e full t hread len g t h of th e pl ug - no th rea d p roble ms . It is rep ort ed t ha t t he J,!e ne l'al con fig u ra t ion of t he Honda ,1511 he a d r epresents the ep it ome of desi g n; the le ng th an d ve n t uri pro por t io ns o f t he manifolds, t he a ng-Ie an d s ize of th e va lves , e tc . Honda wa s a ble to s prea d th e va lves a s wi de apar t a s necess n ry to ac h ie ve ma x imu m s ize a nd flow cha ra ct e ri s ti cs s inc e hoth inta ke a nd ex hau st va lves ha ve ind ivi d u a l ca ms ha ft s wh ose pl acenu -ut wa s u ni nh ibi te d in t he o rig inal desi gn. Wi t h t he DO ll e set u p, t he va lve tips can he s p read a s far apart a s necessa r y to J!c t the la rg es t va lve head s poss ible in re la t ion to th e bo re , with ea ch cam s ha ft pos it ioned cl ose to t he vai n ' tip . Inle t a nd exhaus t valves a re hoth 42 ~ f ro m th e cylinde r axi s for an incl uded a ngle o f 8 ~ ', com pa r ed t o the 7 0 ~ co mmo n in f orm e r sin g le ove rhe a d ca m des ig ns wh e re lo nge r and hea vie r ro cker arm s would ha ve hr-en neces sa ry to reach t he wide r -sp r ea d va lves . T he two ind iv id u a l ca m s ha f ts, dri ven by a co mmo n cha in , a re ca rried in pla in bea rings a t eac h e nd on ly . A ppa re ntl y th e hef t of t he sh a f t s , and wh a t e ver s tea dyi ng effec t is rea lized through cha in te ns ion, p rev ent s e xce ss ive s ha f t wh ip bet wee n cen ters, Di s torti on from cam press u re s a lso woul d a ppea l' to be m inim a l s ince t he ca m lobe s a re rig ht out ne x t to the hearings, Ben ea t h ea ch ca m lobe is a ca m f ollowe r , it s p ivot ed end eccen tri cally mou nt ed on a cross -s ha f t p a ra lleli ng the camsh aft. T he rad iu sed t op side of the foll ow er's other en d work s directl y off t he ca m lobe, wh ile its bottom t ip con tacts t he va lve s te m, Becau se t he TOP -Xofh iug ee n t inic ntal, j lls t !/ O;HO f or the ;gn itiol! »u-it cli uude r the tank . Tun k cupClc ify is al 'e ,. ~ lIal/ous . C he ck r ubbe r ca ble g nitl es 0 11 fron t [ ender f"l d big du ul -c u m bra ke t ha t's so effect ive, L W'!/ e ('u j ludt y nw d 't'1'.-.; are botlt quid ami uf 100C re etrict ion « ! lIif/" sJ1e e d ~ , , l il O F f: - B ig rubb e r pud,s h iuyr a ",1 i neu la t« a t'el 'Y comforta ble d uu l se a t, Ba t t e r u is 1I ('/d by s imple 1'/,1111('" Sfrt l p. A i ,. filt er» a l'e cOl'ered by sid e J>a n el.~ .