Repsol Honda could regret its decision to sit out the Aragon test come September's race weekend, if Jorge Lorenzo's comments about set-up prove true for the RC213V riders.

Casey Stoner and Dani Pedrosa were the two main absentees from Wednesday's test, which followed a post-race outing at Catalunya on Monday, due to the new-spec front tyre not being made available at Aragon.

MotoGP World Championship leader Lorenzo led an all-Yamaha top four at the Aragon test, as he put further mileage on a new engine and electronics package, but also claimed it hadn't been easy to dial-in the 1000cc bike.

"This test has been very important because it's not easy to find the best set-up for the 1000cc bike here as there is so much change from the 800," said Lorenzo, who finished 0.255s ahead of Ben Spies.

The counter argument from HRC will surely be that working on set-up without the tyre spec available for the race is of limited value.

But Yamaha also had new components test and while the revised electronics seem popular, the engine is less clear cut.

"We tried the engine again like we did in Barcelona, there wasn't so much difference so the engineers now have to make a decision for moving forward," sad Lorenzo, who holds a 20-point lead over reigning champion Stoner after five rounds.

"They will consider the data from today to help them."

Lorenzo's best lap, of 1m 49.187s, was just a fraction outside the official lap record set by Stoner in last year's race.

For Spies, who led the majority of the day, the test marked a further chance to rebuild his confidence after a tough start to the year.

"Today was a good test, to come back after not such a fantastic race on Sunday and be consistently fast here and in the Catalunya test is important," said the Texan.

"We've worked really well with the bike and the electronics and just tried to change a few things and fine tune.

"The track was a lot better than we thought, we were expecting it to be quite dirty but it wasn't. I feel like I'm getting back up to the potential of the bike and myself which is good."

The Factory team-mates were followed on the timesheets by satellite riders Cal Crutchlow and Andrea Dovizioso.

The Aragon race weekend, round 14 of the 2012 season, will take place from September 28-30.

Lorenzo and Spies will be back in action along their MotoGP rivals during the British Grand Prix at Silverstone next weekend.

The new spec front, already popular with the Yamaha riders, will become standard from Silverstone.