Cycle News - Archive Issues - 1990's

Drysda/~ 750-VB Superbike (Left) The next step may be the production of several forms of the Drysdale VB, including this vers ion, patterned in the vein of the Ducati II Monstro. A monster indeed! (Below) One man's dream: Graduat ing from his radica l Dryvtech 2x2x2 concept, Ian Drysdale has guided and prodded the Drysdale to fruition. What's next, Ian? 26 Th e change hel ped keep eng ine tempera tu re d ow n to 75 d eg rees o n a h ot summer d ay at Broadford. After in itial oil-surge probl em s ran a bearing on the cran k at the Oran Park Six-Ho u r race a yea r ago (resolved by baffling the s u mp ), the Dr ys d al e V8 m ot or has pro ved fundamentally reliable, sa ys its creato r. Eve n so, w e had a couple of . minor hiccu ps on my test da y, one when the clutch circlip p opped o u t (easily fixed ), the other when Drysdale forg ot to switch the fue l pump on for one of my four sessions, meaning I coasted to a halt at the first turn wit h a dead engin e. He paid for it, th ou gh! He must have lost at least five pounds running d own the pit in the su mme r heat of the Aussie ou tback to flick it on aga in, as I grou nde d th e s ta r ter m ot or in vai n , a n d prom ised to flatte n the twin 12-vOIt batteries now mounted in the nose! Th ese batteries power the Vance & Hine s Powerpak d igital ignition mad e to Drysdale' s spec's by the America n Tuning Hou se. . "They w ere very helpful on ce we assured them that the specified redline of 17,000 rpm wa s correct!" Drysdale says. The sys tem, which replaces the tw o Yamaha COl b lack boxes fitted to the st reet prototype, is progra m mab le for four differen t YZF600-based advance cu rves and revli miter settings. Drysdale hopes to re tai n the V&H Pow er pak in co n ju nc tio n wit h th e EFt because he says it wo rks so well. Fo r th os e in n eed of a r e fr es h er course in the archi tectu re of the only V8 motorcycle in the wo rld, yo u can actual ly purchase (unti l Morbidelli so rts out a new ma nu factu rer for his , that is, and Norton , well, 'till Al Melling actuall y produ ces a h om o log ate d V8 st reet motorcycle anyone can bu y...), the Drysd ale uses as large a number of Yamaha p roprietary parts as possib le to allow customers around the wo rld to source s pa res easily . For insta nce, the 750-V8 racer uses two FZR400R 16-val ve cylind er heads mounted on a horizontallvsplit crankcase , s pecially designed by Drysdale (himself a qualified draughtsman ) to inco rpo ra te the blocks of each bank of cylinders in the upper crankcase half, for added rigid ity. The two banks of cylinders are set at 90 degrees to each other for perfect primary ba lance; and with the central cha in cams haft drive of the Yama ha slan tbloc k engine for ma t reta in ed , Dry sda le has been ab le to rever se the cams ha fts and rota te them backw ards on the rear se t of cyli nders, wh ile those on the fro nt ban k, as well as the crankshaft, all ru n forwa rds . Yamaha parts reta ined on the 56 x 38 mm 749cc en gine in clud e conrod s and pistons (eight of each), all 32 tiny valves (21m m inl ets /1 9mm exhausts) and all fou r camsha fts, with cam drive taken directly off th e crank, an d apa rt from the YZF750 gear ratios and wet clu tch, the wheels, brakes an d front fork s are also so urce d fro m Yamaha's 750 sport' bike, res ulting in a half-dry weight (no fuel) of 409.2 poun ds. Drysdale r eckon s that the wei ght cou ld be re duced to well und er 400 pounds with race w he els a n d o th e r weight-saving tackle, including making the handsome Duncan Harrin gt ondesi gn ed bodywork in carbon fiber . Per haps so . But while I'll admit I came to Broadford prepared to w orship at the altar of mu lti-cy linder engine technology , accompanied by the ma gical strains of V8 mu sic, I ended up being at least as impressed with Drysdale's tal ents as a chassis d esigner as I was with his work as a tw o-wheeled concert promotor! The TIG-welded tubular s teel sp a cefra me that ho ld s th e V8 engine is built fro m ERW mild s teel (less p ron e to s tres s fractures than chrome-mo ly, says Drysdale), w ith Du cati-style regulation on th e s id e sp ars a nd a distinctive loop backbone made fro m oval- section steel tube. The result we ighs 24 pounds (not includ ing the Kawasaki ZZ·Rl100 alloy swi ngarrn) - a littl e heavy, bu t per haps inevitably so, with the en gin e forming only a semi-stressed underslung component to keep the V8's whee lbase down to a man ageab le 1415mm - 5mm sho rter than a YZF750 four! Th e Ohl in s rear s hock is loca ted crossways in front of th e rear w heel, and operat ed by a risin g-rate bell-cran k linka ge simi lar to the one on the works Yamaha GP ra ce r two decades ago . With the cra n ksh a ft of th e V8 motor alreadv 20m m furthe r forward relative to the centre line of the whee lbase compared to a YZF75 0' s, there' s already su rprisi ng ly good weight di stribution for the V8 mot or scaling 143 pounds. Complete, but locating the ba tteries up front on the racer has the benefit of fur ther loading up the front wheel weightwi se, for a 53 percent /47 percen t layout. As I settled ab oa rd the bike at rest in the pit lane, I noted not only how the rid ing position isn't qu ite as st re tched o u t as befo re , bu t that the rear ride heigh t is also definitely taller than on the proto ty p e stree tbike I ro d e tw o years ago. This not only helps fur ther in crease fron t end weig h t bias, it also sharpens u p the steering geo me try for track use, which, wit h a s ta tic 24 degree head angle and a hefty 108 mmof trai l. th a t is d efin it ely ..o n tn e conservative side' by spo rt bike ~~and ards - eve n if it is iden tical to ' ¥amaha~ s 'YZF750 spo rtbike, w hich is w here Drys da le go t it froml I rem ember already bein g impressed by the way the Drysdale V8 steered the first time I rode it, but that was on the relatively wide-open spaces of Calder Park. However, the first flying lap at Broadford tells you what an unexpectedly good han- dling package the bike ha s n ow been refined to by its creator. It belies its V8 bulk by steerin g as cleanly and sharp ly as a 750 four, tu rning precisely into the apex of a turn without fallin g sud denly over on its side, as you migh t expect from such a big, bu lky bike. The front end is espedally confidence-inspiring: Broadford has a couple of turns that pose a stiff exam for front end grip , like the last tum onto the pit straight, or the downhill hairpin at the endof the top one, where you must commit to the blind entry and be read y for the track to fall awav beneath vou on the exit as you sw itch the power 'o n. The Drysdale passed the test with flying colors, the front en d plan ted to the ground than ks also to the wo rks-spec fron t slick kind ly do nated by the Dunlop race service when the Drysdale performed some demo laps a t the. Phillip Isla nd World Su pe rb ike rou nd . The bik e not on ly stops ver y well, wit h those six-po t N issins giving lots of bite, but rea lly, it steers su rp risingly easily a nd precisely, too , w it h im p ressive handling for what looks like it wo uld be a beefy, tir ing bike to lu g around a tight track like Broadford. On ly it isn't. It s tays on li ne ex it ing a turn u nder power, with no undue understeer , and the liqu id-smooth power curve at high er rpm en sures th er e are no s teps in the deliverv ready to unh o ok th e back wheel \~hen yo u get hard on the gas exi ting that d ownhill turn. or aga in when vo u accelera te ha rd o u t of th e uphill 'turn b ef ore it, w ith th e fro n t whee l waving in the air as you crest the rise . II felt fas t, bu t not fickle. Bu t th e rear Dunlop was read y to wa lk und er po wer, cha ttering slightly as yo u fed the revs in, and yo u could feel the Ohlins shock bouncing back abru p tly off b ott om . It felt li ke to o little rebound dam ping, for su re - but also I think the r ising rat e linka ge h as too stee p a curve, and ma ybe the spring was too soft for my weight. A mor e linear rate linkage w ou ld be bett er for street u s e, for s u re, but on th e r a ce tr a ck w hat's needed is a good da y' s sorting session with a suspensio n techn icDrys d ale on hand . So far, the tea m's never had the time or facilities to do this. But they need to, beca u se o the rw is e th e chassis is 'really, rea lly good, an d ideally compliments the V8's performance. But a t th e e n d of th e d a y, what's most impressive about the Drysdale V8 is that this is the product of one man's ge nius - plus his own drive, d ete rmination, technica l expertise and ability to charm countless friends into wanting to join the pa rt y, to help him make it all happen. Ian Drysdale had the vision to conceive the 750-V8 in the first place, a a modern-day tes ta m ent to th e legendary Moto Guzzi V8 GP racer . The n he drew it up himself on paper, he fashioned a la rge p art of it with his own hands, and he assembled it in his wo rkshop together w it h h is team o f fellow visi onaries. He has used h is ow n time; money, vis ion and expertise to make a drea m co me alive, fas hio ning it fro m metal. Now that the streetbike spi noffs are u nder way (see sidebar) tha t will put the project i n to a com mercial con tex t it's time for the 750-V8 Superbike race tq beseen- and heard ! " in action by-, wi der public. - .,. Let's ho pe ' tha t Drysd ale' s d ream t race the bike in Japa n or the USA, ora t a ". m ajor Europea n fou r-s tro ke even t lik e " the Du tch Ducati Club 's Asse n In tern ational. can come tru e. Then, for 'specta tors aro und the world , the m ulti~cylin- · d er sound of mus ic will play aga in..• eve n if they d o end u p co pp ing o u t;;of go ing d own th e sa me route in G rand Prix racing! _

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