Cycle News - Archive Issues - 1990's

RACER TEST calipers. Target weight of the production bike with full street equipment is 395 pounds. "We'll be using maintenance-free PTFE-lined rod-end bearings on the steering," Stevenson says, "which have done over 15,000 road miles and two seasons of intensive racing, in all kinds of weather, without developing any play. Just don't power-hose them, that's all. They're the same as Ducati use on the rear-suspension linkage of the 916 and Monster, where they get a much harder life from all the chain oil and dirt thrown up off the back wheel. So we're satisfied about the practicality of our design for everyday use on the street." Okay - but is all this worth 20 big ones in Her Majesty's coin of the realm? That's a sizable sum by any standards, that would buy you, say, a KTM Duke for hot-rodding hooliganism, a Suzuki GSXR600 for supersporting street action and a Triumph Trophy 1200 for the long haul. Or throw up just about any comparable three other bikes you can think of (okay, or one-and-a-half Bimotas of your choice!) all against a single, admittedly hand-built but nevertheless proprietary Japanese-engined ASP. Home-brewed hi h·tech Part II Riding the ASPl at Mallory Park exactly two years down the road after first making friends with Andy Stevenson's Pet on the same circuit was a satisfying experienre. How come? Well every singJe ailicism I had about Stevenson's first creation has now been resolved. Any chance of some paid empIOymellt as a devefOpn\ent rider for Britain's newest bike manufacturer? I better not put the down-payment on that time-share in Maui just yet, though - because the guy who's reaDy responsible for the quantum improvement in the ASP2's on-track attitude is Stevenson himself, together with the bike's owner Stuart Jones, who's been road racing at the National level and above for even longer than me, in the course of which he has learned just about all there is to know about how a big, four-cylinder hyperbike should handle. That knowledge has been shared with Stevenson, who's matched it to his own test-riding impressions, then translated the result into metal. First. though, a refresher course in how the ASP chassis package works, built around the Yamaha slant-block motor which. Stevenson says, is tailor-made for a hulxenter chassis design. "The engine castings have so many brackets and lugs attached to them from where Yamaha have used various versions of the motor for different models - including of course the hulxenter GTS - that it's perfect for bolting the front and rear suspension to, especially as the engine's anyway so strong," he says. "But we didn't really take full advanta OIl this with IIDe first ASP, so a main priority with the A5P2 was to save a lOt of weight and use the engine as a fuUy stressed dYssis member by doing away with the lower engine cradIe the fintbike had." The newer bike also uses a different versioa:l of the 2O-valve motor, here the YZF750 Supl!rbike package with full-factory race kit, rather than the tuned-up 1002cc EXUP motor of the ASP1. Power output is about 10 bhp less, but !be less !orquey, smaller engiDe revs much higher and more eagerly, providing a sterner test of the ASP chassis package's ability to put that power to the ground. Fortunately, instead of the anachronistic twin rear sboe:ks fitted to the otbenvise so-avant-garde A5Pt, Stevenson has now opted for a more modem monoshock rear end. though to begin with he chose a singJe-sided swingarm. that unfortunately only permitted use of a S.50-in. rear wheel. The inevitable wheeIspin problems this produced with t2S-bhp pIus - ewn with the s1icks now fitted - were resolved with the arrival of a conveational braced swinprm with MaxIm lUI' shock. piV'illiDg in the tnmcated teINllns of the original Y2F twin-spar da!8is. A m.atchirlg swinpnn belluIifaDy fabrica.led by NWS is used at the front, pivoting in a pair of alloy plates bolted te the engine castinp. with a tubular sll!e1 upper .....,mame 10cating the slleering system. 11Iia syslIml C8IIIiIb tX a pm tX triple c:1Ianps mtatiag ill top and bolIDm tapaed ~beadnp.towllidl6e...., s moe atbldlecL 11le bcIl:Ima tdpIe d8mp Iwa II .......enaf ~ which is " Ie! ....... ~ , Jewer _ tX an c=:..,.-- Utfdlifts. &alit~ me pWaes the .,apt Ioc:.eIac the lIIt:ictl1IIllId, pm of side wheel. and I • piIlGt _ . tabaIar CIllIIII'ClIs .... . . . , paptIJy _ - . . N ' ' ,. . . . . . . . . . In a ftlIic:Il plane. 1tIent'.no oIlIJ aWjoaItilll.""-acn. IOdls from to __. _ ' " tJ.wIIeel mra1fts _ _ ....... the81e fnlats' 8 'n to~ . . . . . . . . . . . . . . . . 1I1 ~ ..... 'I1IeIl!'S"J!l§lrt tap.Gf 1IIDckJl6i": otiIIg_thetplt !leW. ' t: 114_ ,.of_be I 'It 't ' ....:2. ;·01........ ....,.......1Ie ~ "';:t.tD 28 • the 6IDIlf-. _ .......1 •• _4hHelIt '1 ~ . . f 41. F! • ... ... lIiiIlIl"'_JaIhsIRllt ,. __ ~ ..,....... -il". I""'~'" ~"1!U'_ to • • 11w InoIClVdva ~ front. IIplnalon ....... faIrty slmpla and ~ .nIIctIft • f-.I from the fronI ........ uclllst . . . ......:aIon 8CIIon undar '-vylnldng. Andy Stevenson has his sales pitch ready. "The ASP is a lot more intuitive to ride than a conventional sports bike, because the feedback from the hub-center front end is brilliant," he says. "It has the performance of a Triumph T595 Daytona or Honda FireBlade, but it turns like a 250, because of the extreme steering geometry we're able to use. We're offering a radical alternative for the thinking rider in terms of chassis and suspension design, which will unlock new horizons for him, and allow him to ride harder and faster more safely than he thought possible. The evo- lutionary cycle is swerving back toward the situation in the early '80s, where engine performance outshone the ability of chassis design to keep up and allow the rider to take advantage of the extra performance on offer. I believe the new generation of four-cylinder engines from Japan requires a new concept in chassis technology to exploit their full potential in complete safety in real-world riding conditions. The ASP is our solution to that need - it'll be an even better road bike than a racer - and well worth the expense." Okay - start the countdown. (N all the tiIM. Perfect. The A5Pl also steers just as precisely as before, with a light, deft action that is far removed from the steering response of a telescopically forked bike, even one with GP-style race geometry, and gives notably more feedback from the front tire than I ever got in three seasons of racing the works Bimota Yesi. But the big difference is that now there's no tradeoff for this outstanding steering and front suspension response if you ride the bike at something less than race pace. Instead, even at license-friendly speeds worthy of city streets, the ASP2 behaves exactly as a conventional tele-forked bike would, even if you have a hard time convincing yourself that's what you're riding judging from the view beneath your hands. It's been taught table manners that augur well for the street version. However, this has been done in an unexpected way, which doesn't in any way sacrifice the whole advantage of a hulxenter design like this that offers ctirect steering and a total absence of bump steer - even over the worst of the Gerards ctips and ripples. The fabulous British-brake cocktail of PFM cast-iron discs and new-generation Harrison Bi1Iet-6 calipers which (a) have improved pad choice and (b) have been redesigned to stop spreading under a hard squeeze, deliver stopping power the equal of anything this side of a factory Yamaha superbike. But of course on the ASP2, you have the added benefit of being able to trail brake deep into turns without fear of the suspension freezing, because of the hub-center design. You just have to convince yourself you can do it, and while it's a couple of years since I last tangoed with Yesi, after 20 laps of Mallory on the ASP2 I was starting to reprogram my self-<:onfidence software. You don't need to ride the bike like this on the track to appreciate the advantages of the design, though: Just wait until someone puUs out from a side street, turning in front of you while you're leaned over on the angle, then see what happens when you take a big handful of brake! It's a safety factor - ask any Yamaha GTS1000 rider (if you can find one). No, what's frankly amazing is how Stevenson has achieved this confident, easy-steering lowspeed handling. He's actually reduced the trail still more to just 67mm, and the head angle to an amazing nine degrees (yes, nine). When 22 degrees and 80mm of trail is considered extreme for a conventionaI tele-forked bike, this is pretty incredible, but to prove this is the key to the equation, he increased the trail to just 72mm (only 5mm more) for my second session. Suddenly the bike was back to its big sister's habits of penc:lular motion and didn't steer nearly as sweetly. Changing it back showed it was clearly the way to go. Who'd have thought it? Other improvements over the ASPI include jacIdng the rear end up a little higher to load the front end more - frontal weight bias is increased to 56/44 percent, same as my Ducali Supennono and a great recipe for carrying comer speed through turns if you have a front tire that wiD deliver grip, as well as front suspension that enables It to. The Dunlop slick works weD on the track, but after a negative experience on the old A5Pt with a treadcd front Dunlop, which twisted and defonned under heavy bnlting 01" if you tried to max out cornerspeed. After c:IecIariIIg a vested intaest I must recammead SlSteIe'V"'Ci!ll_ _ to try the MW d1aal~ Bridgestolles ' fiMed to the TriaIIIph T59S/T5D9, wIIicb moe just ouperlaIive in teIIIlS tX gnp.oo 6eeI- Triumpb didn't . - . - tMm over Dunlops wiIhoatpld - . And he also seems to have dialed in. 1itt1e _ &oIIt-end diw under heavy InIdng than before, just to stve tM fftIiIIg you teaUy _ mrpping when you squeew Mrd, thoaP dIis is aai1y varied ~ to C\ilIl DaMe 01" rldertalle. One d the most d._ing lIIDIIlLIlt5 .1looIt testing other peopIz's pwU)1lZS or speciaIs is when you __ to tell . . . t1wIy don't wod<. Jl"attilpe U'ound wilibADdy SteWCi_.. begot • EO pzIlCl!IllI . . . -.to and • needs-improwmen .....dtioD r- - n.e ASl'2 _ Ian cIesip. a highly i oar boy !Dded, 90 percmt _ ~ Pat aD,- cap and. P'WI\ seew_JrJ More to the poW. • abows lois d J'I'lIIIl- lor laIkide schaIIIAjp in ::r~==.::, farwant to ; .~ his p!1'~ pm-

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