MotoGP title leader Jorge Lorenzo, who previously compared his 800cc M1 to a 250GP machine along the Indianapolis main straight, once again raised concerns about the straight-line performance of his Yamaha after qualifying at Aragon on Saturday.
The new Spanish circuit contains a long, downhill, back straight, where fellow front row starters Casey Stoner (Ducati, pole) and Dani Pedrosa (Honda, 3rd) were able to reach 324.5km/h and 326.8km/h respectively in qualifying.
Despite qualifying second on the grid, Lorenzo was only able to reach 318.6km/h on the straight, and also feels he's losing out to his main rivals under acceleration.
Acceleration isn't measured by MotoGP organisers, but in terms of top speed Lorenzo was faster than only one rider this afternoon - Tech 3 Yamaha's Ben Spies.
All four M1s were in the bottom five for top speed in qualifying, with only Honda's Marco Simoncelli slower than a Yamaha.
"I'm riding good and every lap I improve my riding style and understand the track, which is not so easy," began Lorenzo, after extending his run of successive front row MotoGP starts to 15.
"The problem is that we lose a lot on the straights and under acceleration. We don't have the same power as the Ducati and Honda, so this is the worst point we have now.
"But anyway we can't change the bike, so with this bike we must be perfect and ride perfectly to have some more chance of victory or a podium tomorrow."
Lorenzo starts round 13 with a 63 point lead over Pedrosa and has finished on the podium at every round this year.