Ducati riders Nicky Hayden and Andrea Dovizioso believe major changes are needed to the 2013 bike after a poor start to MotoGP testing at Sepang.
All four Ducatis lagged behind the Hondas and Yamahas throughout the week, struggling to get above the lower top-10 places and never getting within 1.5 seconds of the lead pace.
Hayden acknowledged that the Malaysian Grand Prix track was not Ducati's strongest venue, but said the time for small upgrades was over.
"We obviously can't be happy when our times are that far off of the top guys, but we knew it was going to be tough," he said. "Sepang has never been a particularly good track for Ducati. We raced here in October, and the bike hasn't changed much since then.
"We found a couple little things over the course of the test, which allowed us to improve our consistency on day three, but I think we need something big."
New teammate Dovizioso, a former works Honda rider who joined Ducati from Tech 3 Yamaha, said the test at least showed the Italian squad the task it faced.
"We're here to improve the situation and everybody knows the level we are now so we have to improve," he said. "We tested as much stuff as we could, because we're focused on improving the bike. The gap to the others is big, and we pushed a lot to understand the bike.
"We don't know how the next test in Sepang will be. There's too short a time between now and then, so it's difficult to do something big in this time. We still have to decide which parts we can bring to the second test. Unfortunately, we need time to try something big."
Ducati MotoGP director Paolo Ciabatti admitted the test had been an unpleasant experience.
"We knew we were starting from a base that needed significant development work, but it's not nice to realise we're still so far from the leaders," he said.