A late fast lap by MotoGP title leader Jorge Lorenzo put the Factory Yamaha star on top of the Aragon test timesheets by 0.255s over team-mate Ben Spies.

Spies had been fastest for most of the day, at a test notable for the absence of Repsol Honda riders Casey Stoner and Dani Pedrosa.

HRC chose not to make the journey from Catalunya, where Monday's post-race test was held, since the new specification Bridgestone front tyre - which Stoner and Pedrosa are currently struggling to find a set-up for - was not made available at Aragon.

Some of the CRTs were also absent, but 14 of the 21 full-time riders took the opportunity to test at a venue which will host round 14 of this year's world championship in late September.

The main task for Lorenzo and Spies was to further evaluate a new engine and electronics package, whilst also working on finding a 1000cc set-up for the Spanish track.

Lorenzo rode for 59 laps (his best being the 57th) while Spies - who has suffered a nightmare start to the season - gave his confidence a further boost during a similar 57 laps (best 55th).

Following the factory M1 riders on the timesheets was the satellite Tech 3 Yamaha pairing of Crutchlow - half a second behind Lorenzo - and Andrea Dovizioso, a further two tenths down.

Dovizioso, fastest in Monday's Catalunya test, continued his work on electronics, engine, and track set-up, while Crutchlow made up for lost time after suffering a heavy fall early in the Catalunya test.

Pramac Racing Team's Hector Barbera was fastest Ducati once again in fifth (+1.009s) as he evaluated electronics, while Nicky Hayden was a few thousandths slower to be the top factory Desmosedici rider in sixth.

Hayden and team-mate Valentino Rossi were not testing the new aluminium swingarm, instead sticking with the standard carbon-fibre design and focusing on bike settings. Rossi completed the most laps of the day (78) and was eighth fastest, 1.182sec from Lorenzo.

Ahead of Rossi was San Carlo Honda Gresini's ?lvaro Bautista in seventh, while LCR Honda's Stefan Bradl finished the day in ninth. After setting his bike up for the track, the German continued work on suspension and chassis stiffness.

Tenth and last of the manufacturer riders was Cardion AB Racing's Karel Abraham. The Czech suffered a hand injury in his early testing fall at Catalunya and only rode for 19 laps.

The CRT field included Bautista's team-mate Michele Pirro, who was fastest CRT in 11th (+3.265s), while NGM Mobile Forward Racing's Colin Edwards set the 13th quickest time as he continued to improve the Suter-BMW's electronics package.

Avintia Blusens' Iv?n Silva was evaluating the part-carbon Inmotec chassis, but damaged the bike in a crash, meaning he switched to the FTR chassis for the afternoon. His team-mate Yonny Hernandez finished the day 12th, while Silva's limited time with the chassis left him last in 14th.

Round six of the 2012 MotoGP World Championship takes place at Silverstone from June 15-17. The event will start with Lorenzo holding a 20-point lead over reigning double champion Stoner and a 30-point lead over Pedrosa.