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/146698
Since all GP road races in those days began with push starts, this was a big enough handicap to rule out the idea - one which Mascheroni didn't return to until this year, after Honda reminded him how well it worked! Bet he's kicking himself - but at least he'd done all the ground work, which perhaps explains how Cagiva was able to produce the V592 Bombardone motor in just 10 weeks after hearing - and seeing - the Honda in action in Suzuka at the start of the season. Watdting the Cagiva mechanics push-starting Lawson's bike into action in Mugello's pit lane and seeing the cold engine lock the back wheel as they did gives a sense of deja ,vu - only when the engine is eventually persuaded into life do you pinch yourself' to realize it's not the. Ducati mechanics trying to bump-start one of their lusty V-twin four-strokes, but their similiarly red-overalled Cagiva colleagues! But thanks to the off-beat harmonic variations of the twin-crank V-4 motor, with all four cylinders firing within 'a bit less than 90 degrees of crankshaft rotation', according to development engineer· Andrea Goggi, the hard-revving two-stroke has the same leisurely lilt as its four-stroke cousin, even if the throaty exhaust is a lot more high-pitched than the 90degree desmo V-twin. "The first time I tested the new motor, I couldn't believe a race bike engine could sound so bad," said Lawson at Assen. "It made a noise like a tractor and seemed to vibrate like one too. It felt slow out of turns, wouldn't slide the back wheel, and didn't seem to accelerate. Then I saw the lap times, which were faster than with the old engine!" That's when Eddie became a believer. Vibration saps power, and Cagiva's GP technical boss Riccardo Rosa, a 36year-old addition to the Cagiva brain trust this season after six years at AHa Romeo, three at Ferrari and a season in charge of the Fondmental Fl car racing team in 1991, who in spite of his modest demeanour obviously deserves a lot of the credit for hoisting Cagiva up into the top rank this season, admits this was an early problem with the Bombardone that they've worked hard on reducing since Assen. Riding the bike at Mugello, the vibration is now no more than on the Suzuki, which has a similar engine design, with twin contrarotating cranks, no balance shaft, and a near90-degree firing interval. On the Cagiva, two pairs of pistons still fire together, but to reduce vibes it's the diagonally .opposed cylinders which team up - front left and rear right" fire together, followed just over 80 degrees later by front right and rear left. Cagiva's oscilloscope initially told them the NSR500 motor fired over a 66-degJee rotation to begin with, but they've now revised this estimate to 72 degrees, says Rosa. Narrowing it this much on the twincrank Cagiva engine may have led to unacceptable vibration, but one thing is sure: unlike Yamaha (who may have gone for a narrower angle with their big banger), Cagiva suffered no engine failures with the Bombardone after it appeared at Assen, where Alex Barros' third place on an engine they only track-tested for the first time four days before was an excellent reliability 'exam. However, Rosa admits Cagiva is experim