Petronas Yamaha team manager Wilco Zeelenberg has confirmed rumours that Fabio Quartararo has extra rpm available for the final rounds of his rookie MotoGP season.

Quartararo dodged the question after leading Friday practice at the Thai Grand Prix, saying: "We need to see with the team, but... First of all, Yamaha gave us a good bike, we made a good position, so I'm happy."

The Frenchman's cheaper-spec M1 package includes having the 2019 engine, but only five changes for the season rather than the full seven allowed by the rules.

Fewer engine changes meant a suspected drop of 500rpm was needed so that each of Quartararo's engines would last longer.

But Quartararo is currently only on his fourth engine change, so has one more left. That puts him equal on engine usage with Morbidelli, Vinales and Rossi, who are all on their sixth engine and so also have one to go.

Therefore, Quartararo would seem able to complete the season on the planned five engines, even if his rpm is now increased.

Speaking to Dorna's Simon Crafar during FP3 at Buriram, Zeelenberg confirmed that the mileage extracted from each of Quartararo's engines so far means he has now been 'allowed' by Yamaha to use extra revs in the final five rounds.

"We have the same package as before, but we are now into the last races of the season and know exactly where we are with the engine mileage," Zeelenberg said.

"So we are allowed to have a little bit more rpm in case we need it to backshift into the corner for example.

"But it's the same situation as the rest of the season basically, so stay in second gear or shift to the next gear. They can play (with the rpm in each gear) and it's all up to Yamaha."

The Buriram top speed charts showed Quartararo matched the peak speed of the factory machines of team-mate Franco Morbidelli plus official Monster Yamaha riders Maverick Vinales and Valentino Rossi on Friday, adding weight to the rumours.

Quartararo - who has some older-spec parts on his bike, including the fairing - has already taken four podiums, three pole positions and holds seventh in the world championship, directly behind Vinales and Rossi. understands that Quartararo will have the same spec machinery as the other Yamahas in 2020.