Valentino Rossi says Yamaha's new engines it is testing ahead of the 2019 season have not made “a lot of difference” over the '18 motor, and his speed is "more or less" the same as it was this year.
Rossi and teammate Maverick Vinales began work on the new engine, of which there are two specifications, last week in the post-Valencia Grand Prix test, topped by the latter.
Opinion was split, with Vinales calling the new motor 'what he needed all year', while Rossi felt he was still lagging compared to the likes of Honda and Ducati, highlighting continuing tyre wear woes over long runs.
Commenting after the first day of testing at Jerez on Wednesday, Rossi – who was 17th after encountering a late technical issue – says the “way is quite clear” in terms of what engine to continue with, but admitted his “level” is the same as with the '18 engine.
“At the end my position is very bad, but also because we have some problem on the new tyres so we don't make the time attack,” said Rossi, who was 1.7s off the pace on Wednesday.
“My pace is a bit better, but I have to check more deeply the top guys. We continue to try the engine, we make some comparisons and everything.
“The way is quite clear to make the choice in engine [for next year], but from what I feel it doesn't make a lot of difference [over last year's].
“When we ride the bike, also compared to the other top guys, more or less our level, our speed is the same as this year.”
When asked about the late mechanical issue, Rossi says he heard a “bad noise” before stopping, but is unsure what the issue was.
Vinales was once again more upbeat after the first day of running at Jerez, after finishing up fourth fastest and just four tenths from top spot.
The Spaniard feels a “good step forward” has been made, as his pace was better than it was during the Jerez race weekend – in which he finished a distant seventh – and is “more sure” about engine direction.
“Well, I'm actually quite happy. We improved the laptimes from last year, so it means we did a good step forward.
“I've been working really hard for the race pace, because in this track last year we suffered a lot.
“Still we need to decide on the engine, but we are more sure about one spec and we need to keep focusing. I didn't try so much on the set-up, so still I think there is room to improve. “