Valentino Rossi flat out on the new Yamaha at Buriram - but flat out may not be fast enough. Picture: Yamaha Racing

Buriram, Thailand - The evidence from MotoGP’s two pre-season tests so far is that Yamaha is struggling, according to Valentino Rossi and Maverick Vinales.

Italian great Rossi, the nine-times world champion who turned 39 last week, was 12th in the combined timesheets after the latest test in Thailand while his Spanish team mate was eighth. Vinales had been seventh and Rossi ninth at the previous three-day test in Malaysia.

“It was a difficult test," MotoGP.com quoted Rossi as saying after the sessions at Thailand’s new Buriram circuit. "We struggled and we have to improve because we didn’t improve a lot compared to last year - especially with the electronics, so I think we have a lot of work to do.”

Vinales, who finished third overall in 2017, said the factory Yamaha team needed to improve in all areas with rivals Honda and Ducati setting the pace so far in 2018 after also battling for the title last year.

While Yamaha’s main riders have found their bike lacking grip, the non-factory Tech3 team have looked much more on the pace, with Frenchman Johann Zarco second fastest at the Thai test. 

Rossi is hoping for improvements at final testing starting on 1 March in Qatar, venue of the season’s opening race on March 18.

“At the moment we’re struggling,” he said. “But this is today. Maybe in Qatar it will be better.”