Valentino Rossi testing crash cost him mileage with 2018 engine

Rossi went off at the Turn 10 right-hander two hours into the first day of post-season testing, with the high-speed shunt leaving his bike - a 2016 chassis with a development engine - in pieces.

The Italian was unaffected by the crash, logging a total of 64 laps on the day and finishing fourth, three tenths off pace-setting team-mate Maverick Vinales - who also got to try the new engine.

Rossi admitted, however, that getting mileage on the prototype engine was "first priority" - and was hopeful he will get to run it again on the second and final day of testing on Wednesday.

"The first priority was the engine, that is the first prototype of the 2018 engine, but unfortunately I did two laps and I crashed," he said.

"I hope that they are able to fix and we can use the engine tomorrow, so I can understand."

Asked whether the engine contributed to the crash, Rossi said: "No, no, no, Turn 10, maybe cold tyres.

"I was already two and a half laps so I push, lose the front, I don't know if I was a little bit out of the line or [the tyre] was cold, I don't know."

Having reverted, alongside Vinales, to the 2016 chassis for the final race of the season at Valencia, Rossi continued to work on the older specification in the test.

"The day was not so bad, we continue to work, we have a bit more time to work on the 2016 chassis and I feel good, I feel strong," he said.

"The day was quite positive because I have good pace, and also with new tyres I can make a good laptime, I am in P4, not so far from the top.

"And also the feeling with the bike is quite positive, we are able to find the right balance, but the problem is like we know, we have some problem of rear tyre degradation.

"The '16 [bike] is not enough, we need to work, but I confirm that I am able to go faster with the old bike."