Movistar Yamaha's Valentino Rossi gave a positive evaluation of the YZR-M1 after testing with the MotoGP spec ECU and Michelin tyres on day one of the Sepang test.
Last year's championship runner-up recorded more laps than anyone else as he clocked up 55 laps of the Malaysian circuit, slotting into second place on the times with a fastest time of 2m 01.717s – 1.033s slower than team-mate and world champion Jorge Lorenzo.
Rossi has three bikes at Sepang, including the 2015 version, which he used for a few laps to familiarise himself with the M1 again, plus two 2016 machines – one of which is closer to the 2015 bike while the other is more radically modified.
The 36-year-old Italian was particularly impressed with the progress made by Yamaha's engineers on the electronics since the Valencia post-race last November and also gave a thumbs-up to improvements made by Michelin, especially in relation to the front tyre.
“[Yamaha made] big step with the electronics. I expect this because usually when our engineers work on the electronics, usually they fix the problem because they are good,” Rossi said.
“It is something a little bit less sophisticated – it's what we expect – but already the bike is good to ride and in Valencia it was a lot worse, especially on the edge.
“You cannot improve [electronics] to the level of last year because it is like you have a Mac and a computer of ten years ago, so you can work but you never arrive to this level,” he added.
“For me, the electronics is a part that improves always and for sure during the season we can improve. [Biggest difference] is engine brake and acceleration: everything is a bit worse, you can do less, but it is okay – I like.”
Assessing the performance of the new 2016 M1, Rossi said he didn't have enough time to decide which of the pair offered the best potential.
“One bike was like 2015 and we just make some laps for the feeling and after we have two  bikes: one more similar to the 2015 and one more modified,” he explained.
“Today, I concentrated on the bike similar to 2015 because of time, because we have to work on the electronics especially.
“At this moment I don't know if it is better or worse [more modified 2016 M1]. Tomorrow and the third day will be important, especially to try to understand this, the way to follow, also because the Michelin is improved already and the best bike was for the old Michelin.”
Rossi was pleased with the feedback from the Michelin front tyre, although he admits there is still some way to go in terms of development to achieve the maximum performance from the new rubber.
“[Michelin has improved] the front. Already the rear was not so bad but they improved the front and the first feeling is not so bad. You can ride a little bit closer to the limit and a little bit stronger,” he said.
“It's a long way still and we need to improve but also we start to learn and understand what the Michelin needs from the bike because last year we don't know, because with Bridgestone we have to use settings that are very different.
“If you put the setting of the bike with the Bridgestone with the Michelin, the bike is impossible. Now, we start to understand what the Michelin needs to give the maximum potential.”
Asked for his views on the main differences between last season's Bridgestones and the new Michelin tyres, Rossi highlighted a change to his racing line and corner entry as the key variances.
“It's the weight, the balance and looks like the front works a little bit different. Style on the bike, for me, you will see less angle, so less elbow on the track, but the position on the bike will remain very similar,” he said.
“The difference is more the line and the way to approach the corner, braking and entry – more like you ride a normal bike; Bridgestone was more [about] position for acceleration.
“Everywhere [missing some feeling], faster or slow [corners] is the same feeling – it's the entry, especially but [we are] a lot more close.”