Cycle News is a weekly magazine that covers all aspects of motorcycling including Supercross, Motocross and MotoGP as well as new motorcycles
Issue link: https://magazine.cyclenews.com/i/126990
be given them. They go on, and we go faster." Most noticeable to the outside observer have been the new exhausts fitted at Assen, which enable you to tell the Cagivas a mile away in a crowd of bikes - they're loud, and very high-pitched. Apparently they 've not yet been noise tested, but I am assured they would pass - justl The engine is still a contrarotating twin-crankshaft V-4 with crankcase 'reed valve induction, but much smaller and lighter than last year's unit, as well as more powerful: weight of the complete engine is down to 92 pounds from the CI.O/ V's 104 pounds, internal friction is reduced with one less pinion and two less bearings than in the old motor, and the trump card - the supply of Yamaha-esque 35mm twinchoke/single-body Mikuni carbs specially made to Cagiva's design has enabled the goo cylinder angle to be closed to 56°, since there's no longer need to find room for the bulky conventional Dell 'Ortos used before. If this has also led to the sort of difficul ties wi th carburetion settings experienced by Yamaha and Suzuki with their narrow-angle twin-crank V-4s, Roche says that the Cagiva team is learning to resolve these but it was the main reason for the bikes' disappointing showing in practice at the San Marino GP, c~upled with persistent problems With the Kokkusan electronic ignition system which have led to the refitting of the Marelli ignition previously used. The V587's cylinders are made by Gilardoni, chrome-bored with GilnisiI, and have six transfer ports, two large boost ports and a single exhaust. Asso pistons are used, giving a 14:1 compression ratio, measured European-style (of course). The ignition chip also controls the electrically-actuated exhaust valve in each cylinder, which so far has proved the engine's other Achilles heel: it frequently seized due presumably to heat expansion, or else the linkage breaks. Depending on where exactly it sticks in its travel, the bike either loses power (because the height of the exhaust port at optimum rpm has been effectively lowered) or becomes very hard to ride, because the power comes in with a bang, rather than gradually as is the whole point of fitting a power valve in the first place. That's what happened to Didier's bike in the San Marino .Gf' the day before my test, while Roche, who had high hopes of a top three place after finally getting the carburetion perfect by hit and miss between morning warm-up and the race, blew the clutch at the start in his enthusiasm (adding to the growing case for FI car-type carbon-fiber clutches to make ali appearance on two wheels) and even after stopping to pour water on it, was unable to continue. Anyway, no such problems for my test ride on one of the team's spares the next day, and the power valve behaved perfectly. The result is an engine which is immensely powerful ,.gives fierce top end performance, yet IS very tractable. . I. do have some experience of riding 150 bhp-plus 500cc GP bikes, and I can assure you the Cagiva really does have that kind of power, and it doesn't allow you to forget it, . either. Usable power isn't available quite as low down as a Yamaha, but it'll pull cleanly from just over 7500 rpm, with very strong power from 10,000 rpm upwards - just the ' crucial point where the CIO/V used to die a death. However, I would say that the Cagiva has more power low down than the Yamaha, because even with the power-valve you get a really strong urge between ,8000 and 9000 rpm. Then once you get into five figures on the very traditional blackfaced Veglia rev-counter, the Cagiva simply rockets down the track in highly impressive fashion, and seems willing to rev out beyond the 12,000 rpm mark at which peak power is apparently produced: Freddie Spencer would enjoy riding this bike, which is perhaps why Cagiva have reportedly made him such a good offer for next seasonl The only negative point is a very notchy and harsh ~ear change in all ratios, which requires quite a bit of rider effort to utilize. Roche explains that this is because with the original smoother change action the gearbox tended to overselect too easily, so the The V587 is powered by an all-new. reed-valve. water-cooled 66° Vfour two-stroke with narrow-angle crankcase and contrarotating cranks. Cagiva V587 Engine Weter-cooled. reedvalve. 56° V-4 two-stroke 'wit h twin contrarotating crankshafts and electronic powervalve system Dimensions 56x50.6mm Capacity 499cc Output 153 bhp at 11.800 rpm (at gearbox) Compression ratio 14:1 Carburetion ... 222x35inm twinchoke Mikuni Ignition . .... Kokkuaan or Marelli microprocessor electronic Gearbox 6-speed Clutch .•.......... Multiplate dry Chassis . . . Fabricated Peraluman aluminum twin-spar Weight distribution: 52/48% Wheelbase ' 1380mm Suspension ..... Front: 41.7mm , Marzocchi telescopic forks Rear: Rising'rate monoahock with fabricated alloy awingarm and Ohlins unit Head angle 23.5° (variable from 20 to 26°) Brakes ... . . .•. Front: 2x310mm Brembo discs with four-piston . Brembo calipers Rear: 1x190mm Brembo disci caliper Tires/wheels •.... Front: 12/6017 Michelin radial on 3.50 Marvic Rear: 18/67-17 Michelin radial on 5.50 Marvic Weight 2275 lb s, with oil/ water. no tuel Top speed ....Approx. 186 mph The Cagiva V-four was ridden to its best-ever finish in the Brazilian GP when Belgian Didier de Radigues finished fourth. clearances have been taken up to prevent this happening, hence the 'mechanical' feel to it now. Of course, the entire cluster can be extracted in modern "cassette" style , to enable individual ratios to be changed: there's a choice of up to six different ratios for each of the six speeds. The clutch, on the other hand, has a light and progressive action, though the Cagiva would pull out of the slowest corner at Misano, the last left before the pits, quite cleanly without using it, thanks to the power-valve system. ~e After six years of gradually increasing effectiveness on the 500cc GP scene, Cagiva has - unquestionably made the breakthrough with this bike, and for once have been able to keep up with the Japanese in terms of development - all that's needed now is a bit of luck and some improved reliability for them to start finishing in the top three. Whether either of the current Cagiva riders is a potential GP winner against the likes of Gardner and Lawson I can't say - but I've come to the opinion after riding it that their bike is. • twin.-spar. fr!lme. made from Peraluman aircraft alloy. is remarkably stiff. which ehmmates wobbles and weaves under acceleration.