Valentino Rossi’s hopes of getting in vital development miles on a revised Ducati GP12 engine in Mugello were wrecked by an engine management glitch that forced the Italian to miss most of the afternoon session.
The Italian had only completed 23 laps when a new ECU failed at Turn 12 and Rossi crashed out as a result.
The 33-year-old was unhurt in the spill but as a precaution while Ducati technical staff analysed the fault, Rossi was prevented from taking any further part in the test.
Rossi had set a best time of 1.48.565 and he finished the one-day test in 10th position.
Rossi was hoping to use the new ECU at the next race in Laguna Seca but he admitted its competitive debut could be delayed after the technical issue.
Rossi, who finished fifth in his home race at Mugello on Sunday, told MCN: “Unfortunately we lost a lot of time. We tried some small differences in the engine for the future but it is the first part of a package that can make the bike smoother in acceleration. And the first impression was not so bad and also we have some different parts for the balance of the bike.
"I restarted in the afternoon but unfortunately I had a problem with the ECU that manages this new strategy for the engine and the bike stopped and switched off in Turn 12. Fortunately I was already a lot at the edge so I just slide and I was lucky.
"But this problem becomes bigger because we are not able to continue for the afternoon. We decide for safety reasons to stop and that means we lost the afternoon and I have to try another time this stuff at the next test.
"We have the chance to use the ECU in Laguna but with the problem I don’t know if it is a good idea. Ducati remains over the next days to make some tests and maybe they understand more deeply what happened and we will decide next week.
"For me maybe it is better to wait and try to make the test in a better way before using in the weekend of a race.”
The revised engine Rossi tried is also available for him to try in California and he added: “We tried to make the engine smoother in acceleration but this is 20% of the package and we are waiting for the more important modifications.
"They try to be ready for here so we wait for next time. For the real step we have to wait for the rest of the package that will be ready as soon as possible.”
And he tried a new fuel tank to help centralise mass and he said he had gained some agility in the fast corners at Mugello.
He added: “The first feeling was positive because I did some laps before the crash and we gain some agility on the corner and this is one step for next year’s bike. If it works it will be used for the next version but not in Laguna.”