Cycle News - Archive Issues - 1990's

RACER 'TEST Carl Fogarty's 955 Superbike V-twin motor is really that torquey and forgiving, even in 15O-bhp-plus form, so that although it comes on strong at 8000 rpm and is theoretically safe to 12,300 rpm, there's absolutely no need to rev it nearly that high. I found that short-shifting from third to fourth at 9500 rpm around the off-camber left sweeper behind the Mugello pits made hardly any difference to acceleration, but settled the bike better while cranked over, and though peak power is delivered at 11,200 rpm and is held up to the 11,750 rev limiter, changing up at 11,000 or less allows you to max. out that phenomenal midrange punch and take advantage of the ultraflat torque curve that makes the 955 such a fast but forgiving ride. . However, this didn't happen overnight. In terms of engine performance and handling Ducati has done a huge amount of work since the last time I tested a works 955, Fabrizio Pirovano's Promoter bike that I rode midway through the '94 season. Having been one of the first to race a works 955 motor in 96 x 66rnrn form when I rode a Fast by Ferracci Ducati in the '94 Daytona 200, I can appreciate how big a step forward the Fogarty bike represents, and the main improvement is the way the power is delivered. That phenomenal engine acceleration isn't only due to mechanical improvements like the reworked Pentroof combustion chamber giving 11.8:1 compression (it could be higher, but bumping it up any more on an engine with a 40degree valve angle and ~res this big is hard) but above all to hours of patient work remapping and refining the Weber / Marelli EFI/ engine-management-system by race engineers Ivo Bertoni, Claudio Domenicali and their team. With bigger 50mm throttle bodies homQlogated for this season, the 955 was breathing better than ever, too (though for '96 Ducati will be using a 54mm tapered bore to the 995cc motor they'll be using, widening to an amazing 60mm at the head and fitted with a positiveactioll throttle to overcome suction - a desmo throttle for a desmo motor!) Matched to this vital electronic refinement was an equally crucial mechanical improvement, reflecting a rnid-'94 decision by the development team led by Luigi Mengoli and' engine guru Franco Fame to start exploiting the advantages of desmodrornic valve gear to the full. Just as in Fl car racing where pneumatic val ve operation has delivered unheardof engine speeds and cam profiles, so Ducati developed new desmo camshafts for the 955 on their in-house cam dyno, consisting of a cold engine with no pistons running up to 15,()()() rpm using an electric motor! This enabled them to design a set of radical carns with huge duration delivered by steep opening/ closing ramps, though relatively moderate lift (l1mm on the 37mm inlet valves, 10.5mm on the 31mm . exhausts). A spate of rocker break~ges with the new carns was cured by modifying the profile to red uce the peak of acceleration so as to give the rocker an easier time, while problems with th.e titanium valves meant reverting to Nimonic ones for this season while a new composite design is developed for '96 - a titanium valve with the top of the stem made of steel to reduce wear. The Pank] titanium connecting rods and slipper pistons running in Nikasil chrome bores are retained, with a lightened crank assembly which helped deliver that incredible engine pickup. Finally, the perennial Ducati crankcase problem which saw cases.being changed every 465 miles was cured by a new die resulting in a much stronger construction - the works Ducati did 1550 miles at the Bol d'Or this year with no cracks in the cases. Considering that the original die that broke was the same one used to produce Pantah crankcases 15 years ago, it's a mark of how vintage the Ducati bottom-end design is. The new ones are the same, of course, per superbike rules, except that if you look closely, you can see that the boss for the kickstarter on the old Pantah motors has been removed on the new crankcases! The bottom line to all this is that Carl Fogarty didn't suffer a single mechanical failure this season in either qualifying or a race (apart from his failed effort at Sugo to prove man really can fly without wings, Carl's only retirement all year long was due to an electrical problem in the second race at Sentul), and riding the Ducati you can't help but feel how strong and solid it is. It feels unburstable, and it is - but it's also very deceptive. I've ridden V-twin Ducatis all my racing life, soTm used to how lazy and slow-revving that 90-degree motor layout is. But even I wasn't prepared for the con-artist trick Carl's bike tries to pull on you flat out along MugeUo's many short squirts between chicanes, or the main pit straight. Ym( d swear you were travelling 20 mph slower than you really are, because the engine doesn't seem to be revving that hard - only it is! That's when you remind yourself of another of the benefits of (a) desmo valve gear and (b) twin-eylinder engines, provided that they (c) have a slipper clutch fitted like on the 955. 'It's called engine braking, and this season when carbon brakes were banned from superbike racing, it was undoubtedly yet another edge the desmo Ducati gave its riders over the valve-springer fours. The cast-iron Brembo discs fitted this year work fine, with light lever pressure delivering good braking even for all-out stops at the end of the main straight - only they don't have the total stopping power of the black brakes, and on a motorcycle trapped at 182 mph at Hockbheim, this might have been a problem except for what the slipper clutch allows you to do. Having watched Carl braking for the Assen chicane, I knew this is. You could hear him coming all the way down through the gears using lots of revs, into bottom gear while still braking, all without any rear wheel chatter. Then, as he turned into the chicane, he just tapped it into second and used that incredible low-down zonk to rocket out of the tum with the front wheel six inches off the ground. Every lap. Well, Mugello's got (Right) In Ducat!'s concerted effort to cure initial handling woes, one of the steps taken was to use lighter magnesium for the sing" sided swingllrm to Increase weight bias to the front. (Below) A slipper clutch means you cen maximize the substantial amount of engine braking available from the desmo twin - a definite benefit In the abMnce of carbon-fiber brakes. several chicanes, so I had lots of practice doing just that, knowing that with the slipper clutch I never needed to worry about inertia locking the back wheel on the overrun no matter how many revs I used. Magic. Not a word I'd use to describe the setting the Ferrari team has chosen for their KLS speed shifter, though. It's incredibly sensitive and caused me big problems in my first session on the bike - until I stopped and asked which one of the three switches on the bike would turn it off! The pro~lem was compounded by the fact that Carl uses quite short footpegs, so every time I moved about on the bike I found my left foot brushing the shift lever, which at best cut out the ignition and hiccuped the engine like it drank a can of beer too fast, or at worst changed up a gear when I didn't want to. "I had the same problem," sympathized Foggy's teammate, Mauro Lucchiari, "so I had a flat sole made for my boot which lets me slide my foot up and down the rest; away from the lever." Okay, amico mio - but instead, just set the gear shift up differently: Eraldo Ferracci knows how to do it, and even makes his own speed-shifter that works really well. Ask him! Back in action, I noticed that the gear ratios have been closed up quite a bit - only third is the same as on the 916SP roadster - and that bottom gear on the Fogarty bike is quite high. It's definitely taller than I remember on either the FBF or Pirovano's bikes, but that's quite useful for maxing out engine braking, even if Mugello doesn't have a turn where you really need it, especially with all that torque. "Quite right," said Virginio Ferrari, "It's the gearbox Carl asked for at Donington with its three slow turns, which he ended up using all the time - I think because of the engine braking." It figures... At the stage I rode Pirovano's 955 back in rnid-'94, Ducati was still trying to dial in the handling of the new 916based chassis in race form, and it showed. The bike didn't want to carry any corner speed. Being shorter and more nimble than the old 888, you could make it turn all right, but only at the cost of momentum. !t also liked to wheelie a lot. And worst of all, it felt like it wanted to high-Side you when you tried to put the power down out of a turn. But at a Mugello test session soon after that, Ducati cracked it, making a number of Tamburini-inspired chassis changes for a permanent fix. "The main problem was to get more weight on the front wheel, but also to improve traction at the back," says Massimo Tamburini. "We used a 20mm-longer swingarm, raised the rear ride height, but put the head angle as wide as possible (24.5 degrees, though it could be as little as 23.5 degrees thanks to the 916 roadster's eccentric adjusters), used quite a lot of trail (100mm) to create stability, and developed a new rear linkage. We also increased the hollow-rear-axle diameter from 35mm to 50mm but made the front axle solid, and made the rear hub and eccentric chain adjuster bigger, to allow us to pull the wheel further back to increase wheelbase another 8mm." Casting the single-sided swingarm in magnesium rather than aluminium helped push the weight bias forward, but though the bike now handled well, it iUso weighed only 323 pounds. With the Monza ruling, Ducati had to ; add nearly 18 pounds in weight, but of course they had the choice of where to put it. Apart from a non-functioning starter motor, Carl put his lead ballast under the seat - but for 1996 when Ducati has to add another 15.4 pounds Tamburini says they'll make thicker engine castings which will also help reliability, run telemetry all the time, rather than just in qualifying, and fit alloy triple clamps instead of magnesium ones. And an alloy swingarm? "No - we need to keep the rear end light. That's how we made the bike handle properly in the end." And does it ever. There were times when I half-thought I was on a butch version of my Ducati Supermono, the 955 feels so small and light-steering - it's a cinch to £lip it from side·to side in all those Mugello chicanes, and just as on its little brother, you can work the front tire really hard to keep up comer speed without feeling as though it's going to tuck under like before. One of Virginio Ferrari's many smart moves was to hire former Ohlins technical wizard Anders Andersson to work exclusively for his team this season,.and the payoff came in the superb setup of the 46mm Ohlins forks and rear shock. The Ducati feels perfectly balanced everywhere, with only a little power understeer as my extra

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