Cycle News - Archive Issues - 1980's

(Above) The FZ750's generator, driven by a chain off the crank. (Above) Oil sump with level sensor. (Below) Laminated front discs and dual-piston calipers squeal around town. Yamaha says its five-valves-per-cylinder design is the key to the FZ750's performanc~ The bike has superior . high-rpm power without sacrificing middle and low-rpm performance, and gets 53 mpg. 12,500 (the en d o f th e tach numbering ) onetime when the rider wa s payin g more a tte n tio n to wh ere he was going ins tead of th e tach - wh en h e finall y gla nced down th e needl e was at th e en d of the scal e. An d accordi ng to Filice's tuner , Lou Va ll erga of Palo Alto (Calfiornia) Yamaha, Filice routinel y sh ifts h is bik e so me where , between 12,000 and where th e rev limiter (built into the electron ic ignition system) kicks in a t 13,500 rpm . What the FZ750 en gi ne isn't is the .sm oo thest 750 ever built. It vib rates and makes the fairing and mirrors buzz in top gear between 55 and 72 mph; it' s worst a t an indi ca ted 65 mph (about 4500 rpm indicated ), a nd at that speed th e ga s tank resonat es (the less ga s in th e tank.,th e worse it is) and the buzz in th e fa iring a nd mirrors can be felt with a h eav ilygloved h and. The sea t vibra tes a t th at speed, too, but from 5000 rpm th e engine smoothes ou t all th e way to the red line a nd beyond. There are o ther serious fla ws in th e FZ750 's st ree t performa nce . It has th e wo rst sea t in co nte mpora ry motorcyclin g , ca pab le of making th e rider squir m in 25 mi les or less. It blasts th e rider with ho t a ir o n ho t days, although it's n o t as ba d as a Honda VF750 F or Ka wa sak i Ni nja 900. And th e mi rrors, li ke th ose of so ma ny o the r sport ing mot orcycles, show th e in side of th e ri der's elbows instead o f showing wh at 's dire ctly behind - a ticket-begging liability for a m achine that encourages speed ing (if by nothing else, by sm ooth in g ou t at an indica ted 72 mph ). (Thi s sort of mirror co n figu ra tio n leads to wh at yo ung Associa te Editor Matt Hil genberg calls " th e Ninja tw itch ;" in whi ch the rid er jerk s in first o ne elbow, th en th e o the r, every few moments, to check directly behind for suspicio us vehicles.) On th e o ther hand, th e FZ ha s a n o pti mistic spee dome ter; tests agai ns t th e drags tr ip's clocks reveal ed tha t th e Yamaha read 30 m ph a t a n ac tua l 28.27 mph an d read 60 m ph a t a n ac tua l 55.31 mph . O n th e roa d racing track , the re isn' t anothe r 750 so ld in Am erica tha t ca n run wi th th e Yam ah a . Th e GSXR750 Suzu ki is th e o n ly 750 in th e world in th e Yam aha 's league, an d the Suzuki won 't be in th e U .S. until sp ri n g o f 1986. In th e meantime, the FZ750 is he re and available - ex cept in Californi a. Yamaha declined to reduce performance to meet th at state's stricter em issions standards despite California's sta ndin g as a hot-bed for sport-motorcycle sa les. Given th e FZ750's co m bina tio n of acceleration , \top speed, brak es and overall handling, th e machine should co m p letely dominat e 750cc Stock Production classes as soo n as it shows up o n th e racet rack. T he stock Bridgesto ne Excedras o ffer good traction for being or ig ina l eq ui p ment, but they're sti ll not up to sta te-of- the -art afterm arket hi gh-per form an ce ti res a nd will slide if th e FZ is pushed on the track . The foot pegs dr ag first on each side; wit h th e suspension set up, gro un d clea rance is good. T he Fl is dea d s ta b le on th e st raigh ts a nd heading into fast sweepers, once th e suspens ion a nd tir es warm up - the first time around Wi llow Spri ngs ' turn eigh t in a morning test found the Yamaha shaking its head a little all th e way around. Tha t wa sn 't a problem from the seco nd lap on. There was a tenden cy for the front wheel to turn in slightl y in tu rn eight a s th e Yamaha 's peg hit hi gh spots a t stead y th rottle; runn ing it in fullthrottle o n stickier tir es would most likely help th at; so wo u ld shorten ing up th e whee lbase , judging by the ex peri ences o f Filice a nd Va llerga . As th ey ex p la in it , th ey enco u n ter ed the same problem a t the Willow Pro- Am a fter cha ngi ng geari ng and m ov in g th e rea r axle back a little to tak e u p th e cha in slac k. Vallerga says the wheelba se change was less th an on e-quarter- in ch; both Fil ice a n d Va lle rga report th at afterwa rds th e bik e p us hed th e fro nt en d an d turned FZ750 Engine type .... . .. .•• Water-cooled DOHC inline-four Bore x stroke .. . .•• •• . 68x51.6mm Displacement . ... •.... • •• •. 749cc Compression ratio . . • . . . . . . . 11.2: 1 Carburetion (4) 34mm Mikuni CV Horsepower 100.6 bhp @ 10.500 rpm Torque ... . 57.9 lb .-ft. @ 8000 rpm 'A- m il e dragstrip performance 11 .20 sec. @ 120.00 mph Valves per cylinder . . • • .. . .. ; .. . ; 5 Intake valve size 13) 21 mm Exhaust valve size .. . • . • . (2) 23mm Intake lift ........ • .. • • • • • 7 .55mm Exhaust lift ..• • •• • •• ••••. .7 .15mm Included valve angle ..•••• • 25.25° Intake valve timing ...•.•. •• 7-47° Exhaust valve timing . •• , 39-18° (measuring pt.) , , . 1mm ' Intake cam lobe centers 110° Exhaust cam lobe centers 100.5° Ignition Electronic Lubrication Wet sump Redline 11.000 rpm Calculated rpm @ 60 mph . . •. 4600 rpm Final drive •. .•. . . #530 o-ring chain Gear ratios Primary . , 91 /48 ; 1. 8 9 5 :1 45 /16 ; 2 .812:1 Final 6th 26 /24 ; 1 .0 8 3 : 1 5th 28 /22 ; 1 .272:1 4th 30 /20; 1 .500:1 3 rd 32 /18 ; 1 .777:1 2nd . . . . . ... . • . . . 35 /16 ; 2 .187: 1 1st 37/13;2 .846 :1 Calculated speed in gears at redli ne 6th . . . . . . . . . . . . .. . . . • 144.6 mph 5th ... .. . .. .... ... • • • 123.1 mph 4th . • . . . . . . . . . . . . . . . . 104.4 mph 3rd . . . . .. . . . . . . . • , • • . • 88.1 mph 2nd ; 71.6 mph 1st . ••.•.•. . .. .. . . .. . . 55 .0 mph Frame . • .. Steel. rect ang u lar tubing Rake . . . : . .. . • • • • .. .. .•... . 25.5° Trail ...• • . , .• , • . • . • .. • • .. . 3.7 in . Front suspension type . •• Telescopic forks Fork tube diameter 39mm Front wheel travel 5.5 in . Rear suspension type .... •. Singleshock swingarm Rear wheel travel • .• . • • , , • • . 4.7 in . Front brakes (2) 10.5-in. discs Rear brakes . . . • • • • . . • 10.5-in. disc Front wheel 2 .75x16-in. cast aluminum alloy Rear wheel 3 .00x18-in. cast aluminum alloy Front tire . . 120/80-16 Bridgestone Exedra G527 Rear tire . . 130/80-1 B Bridgestone Exedra G528 Weight. empty gas tank • • , 488 Ibs. Weight. full gas tank . . . .. 520 lb . Overall length I • • • • • • • • • • • • 87.6 in. Overall height 45 .9 in . Wheelbase . . • • .... .. . . . . .. 59.1 in . 5.4 gal. Fuel capacity Ground clearance 5.5 in. Seat height , .•. . . •• . . . 31 .2 in . GVWR ' 981 lbs, Colors . . . . . .. •. .. .. . Silver and red Retail price ..... . . . . •. , • .. . $4599 23

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