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NEW MOTOR: The Ducati GP4 will have the “big bang” Twin Pulse motor for the Dutch TT at Assen
Ducati tests ‘big bang’ theory for new race bike
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June 17, 2004
The works Ducati MotoGP team, still struggling to get its 2004-specification GP4 machine on the pace, stayed on after last Sunday’s Catalunya GP to test a new “big bang” motor in which the crankshaft of the V4 engine has been re-arranged to give it an irregular firing order.
GP engine builders discovered in the 1980s that making the then-current 500cc two-strokes fire two cylinders together, producing just two big bangs per revolution rather than four smaller power pulses, greatly improved grip under acceleration coming out of corners and made the bike pull more like a V-twin.
V-twins are famed for mid-range torque and strong acceleration, both desirable on the racetrack but not at the expense of top-end power; the “big bang” layout is regarded as giving the best of both worlds
‘I enjoyed myself on my bike again and we worked really well during this first test for the new engine’ – Capirossi
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Works riders Loris Capirossi and Troy Bayliss each rode a GP4 fitted with the new Twin Pulse motor which was given a shakedown run last week at Mugello by Vittoriano Guareschi and agreed with the factory test rider that that the new engine improves rideability and allows the riders to lap more consistently.
Capirossi said he was pleased with Monday’s 72 track laps and a best time of 1min 44.5sec. The Italian also tested back-to-back against the motor used during the weekend.
'I am pleased with what we did today," he said. "I enjoyed myself on my bike again and we worked really well during this first test for the new engine.
"The Twin Pulse has greater potential than the previous version
‘It makes the bike easier to ride and I feel a lot more comfortable on it’ – Bayliss
. Of course we have to get to know all about it and test it again, particularly to adapt the settings and the gear ratios to its characteristics, but I think we can be satisfied with the first day.
“I can’t wait to get back to being a front-runner!”
Troy Bayliss got back on his Desmosedici GP4 late in the morning, despite Sunday’s spectacular crash, and completed 46 laps to set a best time of 1min 45.0sec - better than he did in the race.
Though still sore, the Australian was also satisfied with the new engine.
“I like the Twin Pulse. It’s a lot better than the engine we’ve used up to now”, he said. "It makes the bike easier to ride and I feel a lot more comfortable on it.
"Just look at my times… they are good despite me not being in perfect shape.
“Tomorrow morning I’ll see how I feel and decide whether to continue testing or go back home for a rest.”
Tuesday’s testing was cut short by the weather. Heavy showers during the morning meant Capirossi was unable to lap with any consistency but he did go out for a few laps to explore the behaviour of the new engine in the wet.
The Italian reported that the GP4 was easier to control on the wet track, much to his relief – the GP4 has a reputation for being difficult to ride in the wet. Bayliss decided not to ride and returned home on Tuesday morning to get back into shape as quickly as possible.
“We are really pleased with the debut of the new Twin Pulse engine,” said team director Livio Suppo. "Loris confirmed that power delivery has improved, even in the wet, and we are preparing for Assen with renewed optimism.
"The first races of the 2004 season were not easy but Ducati is showing that it has the capacity to react quickly and the determination to become a front-runner again.
“I feel sure that we will soon be rewarded with results.”
We’ll soon see; the new irregular firing order Twin Pulse engine has been approved for racing after the Catalunya test and both riders will be using it in the Dutch TT at Assen – a circuit renowned for sudden weather changes and one Bayliss has reason to dislike.
He crashed there three times in one weekend when he was riding for Ducati in the World Superbike series.
Ouch.
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TESTING TIME: Loris Capirossi prepares to try out the Twin Pulse GP4 on at Catalunya on Monday.
HARD WORK: Capirossi put in 72 laps (three times the length of a grand prix race) on Monday and recorded a best time of 1min 44.5sec.