Cycle News - Archive Issues - 1990's

RIDING IMPRESSION • ~ ~ ,. . . ~ Tl ~ b:; 0\ ...... t---.... ...... ~ ,..Q .E Q) 0.. Q) CIl 6 • their verv na ture are heavier than those used in final production. Th e targeted final d ry weight is 396 pounds. Equally, the front sus pension, wh eels a nd brakes o n the prototype are a ll presently so urced fr om th e YZF 750 Yamaha. But the y will be replaced on the final vers ion by Ohlins forks, either Dyma g o r Marches ini wheels, and Brembo brak es . At that s tage, th e rear wheel will increase to a 6.0D-inch rim compared to the 5.5D-inch one used at the moment. Bu t while th e Kawasaki ZZRIIOO extru ded -a lloy sw inga rm fitted right now will be rep laced by Drysdale's own fabrication, the innovative rear -su sp en · sio n design on the bike is the d efinitive one - wit h the Ohlins shock iocated crossways in front of the rear wheel. and operated by a rising-rate bell-crank system very similar to that used on Ken ny Roberts' 1981 works YZR500 Yamaha . GP racer. What goes aro un d co mes around ... Ok ay, I hear yo u: It exists, it ru ns bu t w hat's it like to ride? Well, bearing in mind that my Calder . visit was only the second time the 750V8 ha d bee n r id d e n at all, it was remarkably rig ht. Carburetion was still s ome way off, so tha t you needed to coa x it up to so mew here ap proac hing the appointed rev limit of 14,000 rpm at this stage of dev elopment, rather than crack the throttl e wide o pen and surf the waves of power all the way to the redline . But w h en I too k adva n tage o f Cal der's lon g fr ont s traig ht to ge t it rev ving hard, th e result w as a bl oodcu rd ling ho wl fro m the twin exha us ts that sent a shiver down the spine, and co n tras ted v ivid ly with th e lump y Yank-Tan k burble from th e m ot or a t id le . Drysda le ' s V-eight e ng in e is extremely free-spinning, wi th rela tively little inertia from the lightweight crank, which isn' t so light th at engine speed di es away too fast when you close the throttle for a turn, so you lock the wh eel or kill the engine, or both. There's a rea sonably high degree of flywheel effect: nice balance. The p ower delive ry is a bs o lutely seamless : It feels like an electric motor in terms of the spread of power and also the lack of vibration - there's none whatsoever. Balance weights in th e handlebars are stric tly cosme tic, and all the old cliches abo ut sewing machines apply in spades. You hard ly have to clutc h it to move off fro m a standstill, and th ere' s absolutely no step in the power delivery, jus t more punch the higher you rev it: totally linear, as is the torque curve. The gearshift see ms a bit red undant with this hu ge spread of usable pow er. Howev er , I expect that o nce Drysdale gets some more radical cams in there as he'll surely have to do if he races the Vcelght. let alone for stree t squirreling on rarer road - all six ratios will come in u seful. Right now, yo u don't need to work th e gea rbox too hard, es pecially with the carburetion not yet set up right; but th e cha nge action is cri s p and sm ooth, with a lig ht clu tch aclion a nd the ability to swa p fr om ro ad to ra ce pattern , at choice, in 20 seconds . But wh ile of co u rse it' s th e en gine yo u focus on , the fa ct is that it's the Drysdale' s handling that really ins pires . In sp ite of a cold Aussie wi nter' s d ay, and the D204 Dunlop tires (which aren't th e An glo-Japanese company' s stickies t compo und), I was really impressed with the way the V8 steers - especially with the way the engine' s weight seems to be co ncentrated in the cen ter of the bike, reducing the po lar moment and making Drysdale 750cc VB changes of d ir ecti on tha t mu ch ea sier and more predic tabl e. W~i gh t d istr ibu tion is a commendabl e 50.5 / 49.5 percent, a nd the bike's behavior confirms that even balan ce on the road . You 'd never g uess th at thi s motorcycle had twice as many cylinders as a normal Japanese spo rtbike, because it d oesn't feel he avy o r th e least bit unwieldy - and groun d clearance within th e limitations of th e conditions wa s excellent. I think from looking at the V8 in side view that the crankshaft sits relativel y low in the wheelbase, in turn resulting in a low center of g ravity that aids in changing d irection in a chicane or S-bend . Above all, it yields extra stability around fast, bumpy turns, Amazingly, th e 750-V8 has a 5mms ho r te r w heel base tha n the Yamah a YZF750 in-line four at 55.7 inches - presumably d ue ma inly to the space-saving rea r-suspension d esig n - and wit h the ex ac t sa me s tee ri ng geo metry a s th e Ja panese bike (24-d eg ree h ead a ng le, 108m m of trail), it feel s quite sim ila r, only a little more stabl e, to rid e. The Drysdale also brakes pretty well, the six-p iston Yamaha calipers and big 320m m brakes not only doin g their job w ell , but th e ch ass is a ls o remaining ver y s ta ble w hen you squeez e hard , even o n the an gle. It doesn't sit up and und er st ee r when you d o this, n or is there excessi ve weig ht transfer under heavy braking. And you can trail-bra ke in to a turn without the bike misbehav- ing. Reall y, I w as ama zed by the ha ndling . On ce agai n, just like the Hunwick Ha llam XIR I fir s t rode six weeks befor e, our atten tion has rightl y been focu sed o n th e i n no va ti ve e ngi ne des ign, ove rloo king the ex trao rd ina ry feat of designing a chassis from scratch that works well right out of the box. The on ly c r iti cis m I had wa s i n regard to th e rid in g p osition , which even for m y 6-foot frame fe lt a li tt le st re tched o ut. Th e sea t see m s a little too far ba ck ove r th e rear whee l. and it's also quite w ide betwee n yo u r legs· presumabl y a fun cti on of the r ear cy linder hea ds. Pr obably no thing can be don e to fix this, exce pt to raise the rider slightly an d move him forward a little. Well - it runs, it so unds grea t, it handles even better, and it steers and stops wel l. Drysd a le a nd h is team d eserve huge praise for, aga ins t the odds and on limited resources, concocting a unique multicylind er m ot o rcycl e. Wh il e the Drysdale 750-V8 will need quite a lot of development to make it ready fo r cus tomer sale, it alrea dy ha s all the makings of a very impressive and comple tely unique bike, a s differen t from th e lengthways-engine Morbidelli shaftie as (Rig ht ) Th e rear suspensio n o n t he Drysda le is u niqu e in that t he Oh llns shock sits sideways in fro nt of the rear wheel and Is operated by a ri s ing-rate bel l-crank system. (Be low) Alan cathcart sam pl ed the Drysdale at Calde r In wh at was only t he second t ime It had ever been ri dden. a Yamaha YZF750 is fr om a BMW KI200RS Flying Brick. [ have to ad mit that, before I rod e it, I thought Drysdale's dream of aiming for a H un wi ck Hallam-type exemption to go ra cing with the VB in A us tr a li a n Superbike racing was a little far- fetched - a nice idea, but bound to be too big and ungainly for racing. Now, afte r having ridden it even at th e s tar t of its development cycle, I'm not so su re. The 750-V8 will never be eligible for World Superbik e racing unl ess Flammini ma kes good on its intenti on to ge t th e FIM to r educe homologation num bers to less than 50 bikes . Even then, it's a big com mitment fur Drysd al e to g o raci ng in anyt hing o th er t ha n the BEARS o r Sou nd o f Thunder class. But the fact is that the bi ke handles well enough and has a promised level of en gine performance hi gh enough to ensure it would n't be di sgraced in su perbike racing . And a t abou t $47,750 fo r a co m ple te cu sto mbuilt street b i ke , m anufactured t o order w ith a six-mo nth delivery quoted fro m rece ip t o f deposit. Dr ysd ale may well get su fficient takers to me et th e maxim um annual production of 10 bi kes per yea r tha t he envisages. o ne of these will, how ever , be lO00cc versio ns or even bigger, even thou gh mixin g a n d mat ching vario u s Ya m a ha parts would a llow thi s to be don e qu ite easily. " 1 conc e ived this m otorcycle as a 750 superbike, and that's what I want tu concen tra te o n refining and building:' he says. "We'll be ready for produ ction be fore th e end o f thi s ye ar and wh en we d eliv er th e first customer bike, I'll kn ow m y dream to build the w orld 's m ost ex cl u s iv e p erformance m ot orcycl e fo r th e street wil l hav e come true." A Dream Bike? Yes, indeed... ., Drysdale 750 va Specifications . Engin e water-cooled. DOHC. go-degree V-eight four-stroke . with four valves per cylinde r and central-chain camshaft drive Bore x s t roke . . D isplacement Output . . . . . . . . . . . . . . . . . Compression ratio Carburetion Ignition ................... ...... . . .. " 56 x " 8mm 3 749cc ...... ...... ..... . .160 hp at 17.000 rpm 11.5:1 (8) 32mm Mikuni CV 2 x Yamaha C Ol T ransmis sion •.... .... ... . .. ....•.... .six-speed extractable cassette with gear primary C lutch multi -plate oil bath Cha s sis ' tubular-s teel space frame with oval-section loop backbo ne Suspen.ion Front __ ._ . _. _ 41 mm Yamaha inverted teles copic fork Rear ..extruded-aluminum swingarn1 with bell-c rank, rising-rate linkage and single Ohhns shock Rake/tra il __ . _. . . . .. .. . . . . . .._ 24°/108mm Wheelbase . . .. . _.... 55 .7 in. Weight . .. . 418 pounds (wi th oil/water. no fuel) Weight d istribution. fir _. . 50 _5/49 _4 percent Brakes Front Dual 320mm Yamaha discs with six-piston Yarncbo cebpera Rear . ...•.•. ..• •. . . •. .. . . . . . .single 245mm P10net disc with two -piston Yamaha caliper Wheel s/tires Front 120170 -17 Dunlop D2Q4 Sportmax radial on 3 .50 -inch Yamaha wheel Re ar . . .. .. . . . ..• .. . .180/ 55-17 Dunlop 0 204 Sportmax radial on 5.50 -inch Yamaha wheel Top speed N/A Y ear of construction . . . . . . . . .• . . • . . .. . . . . .. . ... . . . .. . ._ _ _. . _.199 7 Price . . . . . . . . . . . . .. _. . . . . . . . . . . . . . . . . . .. . 547.750 Manufacturer .. .Drys dale M otorcycle Co.. PO Box 285 . Dandenong. Victoria. Australia 3 175

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