Yamaha riders Valentino Rossi and Maverick Vinales were both focussed on solving the rear tyre problems that held them back in Austria during a private test at Misano on Sunday.
No times from the one-day test were released, but a Yamaha spokesperson described the day as being productive despite a rain shower in the morning.
Rossi and Vinales completed over 90 laps each as they sought to find a cure for the severe drop-off that left them well off the pace of rivals Honda and Ducati at the Red Bull Ring earlier this month.
Also on track on Sunday were Honda trio Marc Marquez, Dani Pedrosa and Cal Crutchlow, although the Japanese manufacturer refused to divulge any details on its programme for the day.
Ducati kicks off two-day test
Testing at Misano continues on Monday with Ducati, Aprilia and KTM all in action.
Ducati test rider Michele Pirro will be the Italian marque's sole representative on track on Monday, and is tasked with comparing the two types of aerodynamic fairing that were revealed in Brno.
Factory duo Jorge Lorenzo and Andrea Dovizioso will then take over on Tuesday before heading to Silverstone for this weekend's race.