Valentino Rossi is seeking a significant improvement on Saturday after slipping down the order in FP2 at Valencia in Spain.

Rossi had started brightly as he finished second fastest in the morning session behind his Movistar Yamaha team-mate Jorge Lorenzo. However, he ended the day eighth fastest and almost eight tenths back on Lorenzo following a lap in 1m 31.257s.

The Italian, who has secured second place in the 2016 championship ahead of Sunday's final race, said he was lacking rear grip with the hard tyre in the afternoon and also experienced issues with the Michelin front.

"We start this morning in a quite good way, FP1 was quite positive. Especially at the end, I put the hard rear, even though it was a bit cold, but I feel very comfortable with the tyre and with the bike, and I finished in second place," Rossi said.

"In fact, we continued in the afternoon with the hard tyre, we tried also the hard front, but for some reason in the afternoon, it was a lot more difficult. Especially the rear, it doesn't provide enough grip, enough feeling. After two or three laps, I struggled, my rhythm was not fantastic.

"I follow the practice and it looked like a lot of other riders have a lack of grip with the hard. So at the end we put the soft, we change also the front, because I don't feel comfortable also with the front, and I improved my lap time, I improve my pace, but it's not enough, I'm not fast enough," he added.

"I'm not happy about the setting, about the balance of the bike. In a lot of corners I struggle too much, and I'm not strong enough. So now we check the data, we try to work and we try to improve the balance for tomorrow."

Rossi and new team-mate Maverick Vinales will ride the 2017 Yamaha during the post-Valencia test next week and the 37-year-old has a clear idea of where he feels improvements need to be made with the M1.

"I think that we have to try to improve the performance of the engine. We need to be a bit faster in the straight. And also I think that we have a lot of margin to improve the electronics, and all the engineers are already at work, especially to save the tyre for the second half of the race," said Rossi. "I think this is our weak point at this moment.

"For me, the problem of this year is that during the season, we tried some different chassis, and also during the beginning of the season, the M1 was supposed to be another one, the one with the tank on the rear. But because the tyres are very different, at the end, we always used the 2015 bike.

"Also from this point of view they have to work, and for the chassis, Yamaha is the best, and we have to continue to work, but for me it is more engine and electronics."

Although top end speed is one factor for Rossi, he feels achieving improved acceleration with the Yamaha is more important overall.

"First of all, I think that anyway we will see the new bike maybe Sunday or Monday, but I don't expect an incredibly different bike, because usually Yamaha is changing small details in that way. For me, more than the top end, we have to improve the acceleration, and the way to put the horsepower on the ground with these tyres."