Once again in trouble due to low-grip conditons at Valencia, Valentin🥂o Rossi and Movistar Yamaha team-mate Maverick Vinales felt they had little to lose by making a surprise last-minute switch to the 2016 chassis for race day.

That was the same design that Tech 3 star Johann Zarco took to second 🥀on the grid and went on to lead for 25 of the 30🌼 race laps.

But for the factory riders, starting seventh (Rossi) and 13th (Vinales), the change 😼meant sacrificing two days of set-up work and starting from scratch in morninᩚᩚᩚᩚᩚᩚ⁤⁤⁤⁤ᩚ⁤⁤⁤⁤ᩚ⁤⁤⁤⁤ᩚ𒀱ᩚᩚᩚg warm-up.

"Yesterday night we c🃏hanged the chassis, we take a chassis from 2016 to try to understand the way," said Rossi, speaking in the Valencia paddock on Sunday evening.

"We did this because the programme was to try the [2016] bike at the test on Tuesday a𓆏nd Wednesday anyway. So we said, 'why don’t we try today?'

"For sure it was a risky choice, but with my [2017] bike we know more-or-less where we are and sometimes in a ra🀅ce you can understand more than in ten days of testing."

Despite Zarco's form, there would be no transform✅ation in results for the faဣctory riders during the grand prix.

Rossi finishe🤪d the season finale in fifth - gaining places when the factory Ducatis crashed, but being passed by Suzuki's Alex Rins - while Vinales was a cautious twelfth after rear t🌳yre vibrations.

Both were sure the 2016 chassis gave a better feeling, but with it - Rossi cautioned - came a 🌱recurrence of rear tyre degradation issues.

"Unfortunately, it is not liౠke you put [the 2𝓰016 chassis] and everything is better," Rossi explained.

"It is quite difficult to improve the bike a lot in just one day and at the end I think it was more-or-less the race that I could do with ꦑmy [2017] bike from yesterday. We are in big, big tro🎃uble with the tyres, we don't have grip and it is very difficult to ride.

"But I think we understand something interesting.

"This [2016] bike is easier to ride and you feel better in general. Sincerely, it is what I felt last year when I tried [the 2016 alongside] the n♚ew one! Butജ it is also true that we are more in trouble with rear tyre degradation [with the 2016]. So we have some other problem.

"I did the meeting with the Japanese and they are worried like me. But sincerely I don't understand which one [2016 or 2017] w🐟ill be the base for next 🅷year's bike.

"Something strange that we don't understand is that I was 20-seconds slower than last year, with the same tyres and same chassis. But it is also very strange to und൩erstand why the race was 15-seconds slower than last year, considering the conditions are exactly the same."

Looking to the future, Rossi said further back-to-back chassis comparisons are likely du✤ring this week's officia💟l test.

"Now will be a very important period to try to improve before the next championship,🍰" Rossi said.

"For me, we have to work in different areas to reduce the gap. Electronics side, but also about the dyna♌mic behaviour of the bike. So it will be an important period for sure. I will try to give all my support. Iꦓ think - and especially I hope - that we can recover."

Rossi lost out on fourꦇth in the world championship to race winner Dani P꧒edrosa.