Maverick Vinales credited Yamaha's corner entry and mid-turn gains for helping him finish pre-season testing on top of the timesheets, in Qatar on Monday night.
The improvements allowed him overcome a 10km/h straight-line deficit, but the Spaniard heads into the season-opening race weekend - at the same Losail circuit on March 8-10 - concerned by the M1's continued lack of rear edge-grip under acceleration.
"I felt really good on the bike. But still, if we want to battle for victory, we need a little bit more grip," Vinales warned.
"The bike is great, the Yamaha chassis, as you know, has always been good. But now it's time to work on the electronics a little bit, the power delivery. It's a shame that we don’t have more tests.
"I tried a ten-lap run at the end. It was very cold for the medium tyres but anyway I rode quite well. A good rhythm and I could maybe push a little more. Anyway still there remains the acceleration [issue], we have no grip on the edge and I think it's very important that we improve for the race."
Statistically, Yamaha was the top manufacturer in terms of one-off lap time in Qatar, with all four riders in the top six.
Vinales held off the surprise challenge of Petronas Yamaha rookie Fabio Quartararo by 0.233s with factory team-mate Valentino Rossi in fourth (+0.443s) and Franco Morbidelli sixth (0.452s).
"I think we've improved quite a lot the [deceleration] side, so I can make the lap time. Even in [sector one] if we lose 10km/h [on the straight] I can be fast, because I can close the corner and make a lot of speed through the corner," Vinales explained.
"So in that area we improved quite a lot compared to last year, but on the acceleration side still we are a little bit back from our competitors. So we need to concentrate and go into FP1 with clear ideas to get more grip on the bike."
The Spaniard also suggested that he is having more input into bike development.
"It will take time to understand the acceleration side but it's good that we are on the right way to improve. Now I think I take a little bit of weight in terms of the development of the bike and that's very important."
The turning point, he said, came at least year's Thai Grand Prix, where a radical shift of weight to the rear helped transform the fortunes of the Yamaha riders and seems to have boosted his technical influence.
"After Thailand we take a little bit our responsibility in the team," said Vinales, who broke Yamaha's record losing streak with the M1's only victory of last season at Phillip Island.
"We work together. We try to understand the way to go faster. And I think we are on the good way. But we have to be patient. It's very difficult to find grip in just one day. So we need to keep going and keep trying."
With the top 13 riders separated by 0866s in Qatar, Vinales predicts an extremely competitive season in which a place in the final part of qualifying can’t be taken for granted.
"It's going to be strong this year. I mean some days it's going to be difficult to go to Qualifying 2 because there are so many factory bikes now. I think sometimes we're going to struggle, but anyway we are in a good position I think.
"It's too early [to talk about the title]. I think finally, yes, we've been very constant in the tests, at the front. But it's just tests so we need to see now in the race.
"I think if we find that grip that we need we are going to be very strong…"
Vinales had been interested in working with a sport psychologist over the winter, but has so far been able to improve his mental outlook without the assistance of professionals.
"Finally I arrived to one point that I switched quite a lot my mind, trying to stay relaxed, getting away a little bit of the stress," he said. "So at the moment no [sport psychologist].
"Maybe after three-four races I will go because maybe the pressure or I'm leading the championship or not. At the moment, I'm keeping it simple. I try to go on the bike, enjoy, give my best and give the best comments to try to develop the bike in the best way."
Vinales finished sixth in last year's Qatar MotoGP, but won the event on his Yamaha debut in 2017.
