Cycle News - Archive Issues - 1980's

Peter Clifford at speed on the NSR500 atthe Honda testtrack in Japan. Gard ner slide or a Spencer-style World C ha mp io n sh ip win o n su ch a ma ch ine . It is obv io us ly a ha rder machine to ge t the best o u t o f tha n the NS500 tri p le I tried a yea r ago. T he fou r' s p ow er band may be m ore progress ive bu t th ere is m or e o n tap. dem andin g m ore o f the tir e and r ide r. II was o n ly la ter that I was a ble to refl ect that during m y previous da y' s visit th e HRC the d irector s, M r. F uku i a nd Mr. Ogu ma , po int ed o u t that nex t year 's NSR engi ne wo u ld be mo re powerfu l. more co m pact, lig h ter and th at wit h furt h er use o f titan ium. ca r bo n fiber e tc., th ey wo ul d get closer to the FIM mi nim um we igh t of 100 kg . H ea ven h elp th e opposit io n a nd co ns ider ing the wa y Spe n cer won th e cha m p io ns h ip thi s yea r, I asked th em wh y th ey were de ve lo p ing a co m p letel y new mach in e. They bo th smiled. "We a re en gin eers." sai d Mr. O guma. T hat seemed a co mplete answer. T he engi neers had m ade a good job of the '85 m odel and once a ll th at p ower had been unl ea sh ed a nd the next co r ne r was ap proach in g at a distressin g speed the N issi n bra kes co u ld be relied upon to stop the blu e and whi te flash with p erfect co ntrol. T he bra kes o n the Yamaha were just as p owerful an d eas ily metered but without th e H onda 's TRAC , th e OW3 1 dived a t th e fro n t. co m p ressin g th e forks to th e poi III th a t it co uld a ffect th e feedback from th e steering and threaten ed the feeling of sta bili ty. T he H onda resisted thi s bu t w ith a slig h t trad e o ff if yo u a re tempted to do a touch of bra king in th e m idd le o f the corners . Not a reco m mended p ractice thi s, but so me thi ng th at I d id a couple o f ti mes - ge tti ng in a littl e over my head with th e tigh ten in g o f th e best circ u it. T ouch th e bra kes in th e midd le of the corner on the Yamah a an d th e f ron t end dips as yo u expe ct. If a ny th in g th e bike tu rns tighter. Touc h ing the bra ke o n th e H onda ac t iva ted th e torqu e react ive a nti -dive an d in stea d of th e forks co m press ing a nd crea ting a reducti on in tra il a nd self cen ter ing a cti on , th e increases pressure on the tire co nt act pa tch increased the self centeri ng effect, a nd th e bik e tried to ta ke a w ider I inc. T his wi ll rarely affect the machi ne's usual rider as Spencer is so mew ha t unli kel y to m isjudge the co rner as I did a n d wou ld o n ly brake if a rid er in fron t d id so me th ing that left him with n o choice . R emem beri ng m y r ide on McEl nea 's Sko al Bandi t Suzuki, I had gaine d suc h co n fide nce in th a t ma chine's ex tra o rd in ary bra king performance th at I was hard o n the han dlebar lever a ll the wa y into th e co rner and n ever thought of coasting in a nd ha vin g to to uch th e brakes .halfwa y around . , ! I, • i , I :: l i woold bed ifficul tto say w it h cer- ta in ty tha t th e NS R was no t as good as th e S uzu ki under brak in g ; m ore likel y I just foun d it more intim ida tin g a nd did therefore not brak e as la te or as deep as I wo u ld in a real raci ng situat io n . T here rema ined the in teresti ng co m p a r iso n bet w ee n th e Yamaha an d H onda a nd th e pros a nd co ns of a nt i-d ive. T he H onda cerrai n ly ha d no ne of the Ga ll ina Suzu ki 's very strong des ire to ca rryon in a sta ig h t line under bra k in g to -th e ex ten t w here it o n ly wan ted to co m m it itself to tu rn o nc e - th e bra kes had been relea sed . T he hard est test o f a nti-dive is bra kin g o ver bu mps where the dam p in g m ust still be a llowed to work effic ie n tl y, but a t T su kaba th e o n ly bu m ps a rc the r ip p les arou nd th e last lon g sweep ing rig h t- ha nder. T he NSR tra cked across those wi thou t the least co nce rn , th e Showa sus pe nsion co p ing with a long pa tch of rip p les r unn in g th e len gt h of the curve. Neit her fron t n or back wa vered a nd th e 250 proved as relia ble, a lt hough th e second half o f th e co rner seemed bu mpi er o n the 250 than o n the 500, ei the r j ust because the machi ne is li g ht er o r beca use I was ge ll ing o n th e power s tro nger wi th th e 250 to wa rds the seco nd half o f th e cu rve. Other tha n th at , the 250 a n d 500 bo th beha ved in a remarka bly si mi lar fashi on. At first I th ought th e sma ller m ach in e lacked the sta nd up under braking tenden cy but whe n I ro de it harder ch asin g th e 500, I fo und it did exactly the sa me thin g . Aga in it was m o re in teres ti ng th an wo rr ying a nd co n fir med j ust ho w simi lar th e two bikes are. T hey were of co urse develo ped side -by-si de. T he 250 was built firs t a n d Spencer asked fo r a 500 th a t wa s j u st th e sa me a nd he got precisel y tha t. T he sa me tw in spa r fra me a nd si mi lar brakes a nd sus pension - j u st eve ryt hi ng sca led u p sligh tly to cope with th e po wer o f the 500. O ne th ing tha t d id sta nd o ut swappi ng from the 500 to th e 250 was th e en g ine vibration . T he ja ngl e I got from th e V-tw in reminded me j ust ho w smoo th the V-Io u r had heen . T he 90" four was perfectly smooth . so met hi ng th at m ust hel p prevent fatig ue in a long race. T he 250 had th e di sadva ntage o f longer fir i n g inte rv a ls a n d less we ll bal an ced reciprocati ng ma sses a nd th a t was apparen t whe n it ca me to the push start . T he 500 fire d itself in to life w ith the m os t casua l push . T ry ing the sa me thing o n th e 250 crea ted a st u tter as it fired half as Ireq uenrl y, no t difficult , j us t less rem arkable. T he fo ur was al so easy to ca tc h o n th e cl u tch a nd throttle because o f th e su perb ca r buretio n provided by th e mag nesiu m -bodied twin choke cas ting Keihins. It wa s noticeably q ui cker a n d m o re reli able to p ick u p th an the Yama ha , which still bat tles a lilli e wi th low-and mid-ran ge ca rbu re tio n. T hat was something bo rn o ut wi th th e starts of thi s season 's G ra nds P rix a s the Yama ha s were slower o ff the grid . I wou ld ha ve though t the four was eve n better tha n th e th ree, bu t perha ps the four was sti ll a kil ogram or two h eavi er than the NS a nd h en ce H as la m co u ld get h is triple off th e line q u icker. ' Even p ushi n g the 250 hard enough o u t of th e co rner to promo te a rear w he el sl ide ca use d no heart-sto p p in g d ra m a , j u st a p redicta ble mo vemen t fro m the rad ial Mi ch el in . I didn ' t tr us t th e 500 to be so fo rgi ving a n d havin g had th e fron t wheel come up a t th e w rong m omen t o nce , I was no t a nxious to find th e lim it o f the rea r tir e 's ad hesion . I'll leave th at to Way ne G ardn er or Fred di e Spencer a nd wo nder w i th a greater understa nd ing as they slide an d whecl ie their way throu g h ba tt les wi th th e S uzu kis a nd Ya rna has du ri[1/t ,tDf -1986 .seaso n .. - •. . - - - - - - - . - . . - - • Kaw 1000GTR (Con tin ue d from pag e 18) superi or to Su zuki 's oi l-cool ing system o n th e GSXR fo ur-stro kes. T hev claim th at wi th the co m bi ne d water-cooling a nd oi l cooler the coola n t runs co lder for be tter hea t tran sfer, givi ng m ore po tential for power. Drive from th e cra n ks haft is the sa me as o n th e 900 R an d 1000RX with a gear cut o nt o the cra n k dri vi ng th e cl u tch . /T h e clutch is deri ved from th e 900's a nd uses a diap hragm spring damper in addition to co il sp ri ngs in th e clutch basket. T here's a lso a back torq ue lim iter that a llows the cl u tch to slip u nder heavy en gine bra ki ng. T h e six-speed gearbo x is th e sa me design as th e 1000RX 's wi th a limiter in th e gearchange ma king n eutra l easi er to find fro m bo u orn gears. Ra tios h ave been a ltered to give lo wer botto m and seco n d speeds a n d a h igher , ove rdrive -type to p gear. T hird to fifth are th e sa me interna ll y but th e sligh tly lower fi na l ra tio lo wers the o vera ll rat ios margina ll y. Chassis is based o n th e GPz900R's spi ne type a nd incorpo rates th e engi ne as p art o f th e structure. The difference is th at , unlik e th e 900R 's ligh ta lloy rear su bfra me, th e G T R 's is a lmost a ll stee l tubin g except for a sma lle r a lloy frame su p portin g the rear fai ring . As a result it' s heavier at 5 1 pou nds. Explanation for not usin g rubb er mountin gs fo r the en gi n e as o n the 1000R X is th at lo w speed ha ndli n g was mor e im po rta nt th an the u lt ima te in smooth ness, says chassis specialis t ' Ha n k' H oso i. " T h a t m eant the engi ne needed to be mo u n ted lo w e r than on th e 1000RX , a nd to ach ieve tha t we h ad to use th e 900 R d ia mond frame which doesn't use lo wer fra me tu bes. making it eas ier to fi t in the exh a ust p ipes," h e says. The en gi ne, however, reta in s the double-e ngine-speed ba la nce r from the 900R to th e mini m ize seco ndary vibra tion which ca u ses the high-freq uency buz z co m mo n to in line fo urs. GTRjRX Comparison Kawasa ki 's IOOOGT R u ses a set of wi der gearbox ra tios to su it the e ng i ne's m ore fl exibl e p owerband. Bo th bottom an d seco nd internal gea r ra tios are low er than on th e 1000RX wh ile th e sixth spee d gea rs are swoope d over to g ive a lmost an overd rive o n the GTR . Beca use th e GTR uses a slig h tly lower fin a l d ri ve ra tio wit h th e shaft an d bevels, th ird to fif th are j u st slig h tly lo wer o vera ll th an o n the GX. O vera ll effect is th at wh ile the 1000RX is revving a t 4950 an d 4425 rp m in fifth a nd sixth respectively a t 70 mph with a 10.6%d ifference i n th e ra tios, the GT R is revvin g a t 5000 an d 4175 r p m, giving a 16.5% d rop into top gear. Top gear o n th e GTR eq ua tes to a theoretica l 176 mph at th e 10,500 rpm redl i ne, but of co urse th e 108.5 bhp peak power isn ' t enough to ac h ieve th is. Th e m ore slippery, low er geared an d more powerful RX ca n probab ly pea k in top gear a t 166 mph ill th e righ t co n di tions. Respec tive ra tios and speeds at 10,500 rpm in the gears for the GT R and R X are as fo llo ws: IOO ORX P rimary Final Fi rst Seco nd T h ir d Fo urth Fift h Six th l OOOGT R Pri m ary Fi n a l Firs t Seco nd T hird Fo urth Fifth Six th Internal Overall Mph 1.732 2.666 2.800 12.93 62 2.000 9.24 86 1.590 108 7.34 1.333 129 6. 16 1.153 5.32 149 1.035 4.78 166 1.732 2.708 3.071 2.055 1.590 1.333 1.153 0.965 14.40 9.64 7.46 6.25 5.40 4.53 55 82.5 106.5 127 147 176. Kawasaki 1000GTR Engine type . . . . . Water-cooled. DOHC inline-four Bore x stroke 74x58mm Displacement 997cc Compression ratio .. • . .• 10.2:1 Carburetion . . . (4) 32mm Keihin CV Horsepower . . •• • • 108.5 bhp @ 9500 rpm Torque •• • . . . . .. . 72.3 lb .-ft. @ 6500 rpm Valves per cy linder 4 Intake valve size ...•... . 29mm Exhaust valve size . .... 24.7mm Intake lift • . • • • ••• • . .. • 8 .4mm Exhaust lift .. ... • • . .• • 8.4mm lneluded 'valve angle . . . • • 34.9° Intake valve t iming 37.5-57.5° Exhaust valve timing 57.5-37.5° (measuring pt.] . ... . ...•. Omm Starting system . . • . .. . . Electric Battery rating . . . .• . 12V 18AH Ignition Electronic Lubrication .... . .. ••. Wet sump Redline 10.500 rpm rpm @ 60 mph . . • • •. 3750 rpm Primary drive Straight-cut gear Final drive .. . . . . . . ..•.. . Shaft Gear ratios Primary • . • • • • 97/56; 1.732: 1 Final . . 16 /21x32 /9 ; 2.708 :1 6th 28 /29 ; 0 .965:1 5th 30 /26; 1 .153:1 4th .. ••. •. •. 32/24; 1 .333:1 3rd . •...•.•• • • 35/22; 1 ~ 5 9 0 2nd . . ...... . .• •37/18;2.055 1 st. 43/14; 3 .071 Calculated speed in gears at redline 6th 176 mph 5th .. . .. . . . .••. . • • . 147 mph 4th 127 mph 3rd 1 07 mph 2nd 83 mph 1st . . ... •. . .. • • . .. . • • 55 mph Frame Steel tube Rake •• • • • . .• . • • . . • . .• • 28.5° Tra il. . . . • •• • • • • • • •. • • •4 .84 in. Front suspension type . • . • Telescopic forks Fork tube diameter • . • . . • 4 /mm Front wheel travel . • . . .. • 5.5 in. Rear suspension type ... Sing leshock swingarm Rear wheel t ravel 5.5 in. Front brakes .. (2) 1 0 .6 -in . discs Rear brakes 11-in. disc Front wheel ••.•. . • 2 .15x18-in . Rear wheel 3 .50x16-in. Front tire '. . 110/80-18 Dunlop K105F Rear t ire • • . 150 /80-16 Dunlop K700G Claimed dry weight • • • 584 Ibs. Certified wet weight • . . . . N .A. Overall length • •. • . • . . •• 90 in. Overall width • • • . .• .•• • 29.9 in . Overall height 55.7 in. Wheelbase . . . •. . . . .. .. 61 .2 in. Fuel capacity 7 .5 gal. Ground clearance 5 .5 in. Seat height ... . . .. • .. .. 32 in. Load capacity . •. ... •. 441 Ibs. Colors .• • • •• . • • • . . . . Red. grey Retail price . •. .... ..... $5699

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