MotoGP championship leader Marc Marquez believes acceleration woes means Honda will "struggle" at the Grand Prix of France in Le Mans this weekend.
Marquez leads the drivers' standings after back-to-back wins in Rio Hondo and Austin, but the Spaniard could only manage third behind the Yamaha duo of Valentino Rossi and Jorge Lorenzo in Jerez last time out.
The 23-year-old is expecting another difficult weekend in Le Mans, pin-pointing the circuit's many acceleration zones as a weak spot for Honda.
"Here [Le Mans] is one of the circuits that we will be struggling more, because we have a lot of acceleration [zones] - especially the two big accelerations," Marquez explained.
"We are a losing a lot in [sectors] T3 and T1 - T1 is related from the acceleration on the straight. We are trying to work there. I know that we will struggle this weekend."
The two-time world champion added: "We work on the acceleration side, but it's really difficult to improve because the engines are closed [sealed].
"Still Honda didn't have time to bring something on acceleration, so we are trying to adjust the aerodynamics, but still the winglets are not working perfect.
"In the other side, we have strong points that we must use - but the problem is that, at this circuit, we are not able to use [them] like we want."
Marquez's Honda team-mate Dani Pedrosa topped the time sheets in the first Friday free practice session, while Lorenzo was fastest later in the afternoon.