Following Monday's Catalunya MotoGP test, a further official test is taking place at Aragon in Spain on Wednesday.
The Aragon test is a replacement for the Estoril test, cancelled due to poor weather.
Testing began at 10am and will conclude at 6pm, including a break for lunch.
Repsol Honda has chosen not to attend the Aragon test, as the new-spec front tyre - which will become standard from Silverstone - is not available. Some of the CRTs are also absent.
Round six of the 2012 MotoGP World Championship takes place at Silverstone from June 15-17. The Aragon round will form round 14 of the series, on September 28-30.
1. Ben Spies
USA Yamaha Factory Racing (YZR-M1) 1m 49.636s
2. Jorge Lorenzo
ESP Yamaha Factory Racing (YZR-M1) 1m 49.911s
3. Andrea Dovizioso
ITA Yamaha Tech 3 (YZR-M1) 1m 49.950s
4. Cal Crutchlow
GBR Yamaha Tech 3 (YZR-M1) 1m 50.033s
5. Nicky Hayden
USA Ducati Team (GP12) 1m 50.204s
6. Alvaro Bautista
ESP Honda Gresini (RC213V) 1m 51.138s
7. Stefan Bradl
GER LCR Honda MotoGP (RC213V) 1m 51.146s
8. Valentino Rossi
ITA Ducati Team (GP12) 1m 51.586s
9. Hector Barbera
ESP Pramac Racing (GP12) 1m 51.861s
10. Karel Abraham
CZE Cardion AB Motoracing (GP12) 1m 51.977s
11. Yonny Hernandez
COL Avintia (FTR-Kawasaki CRT) 1m 52.502s
12. Colin Edwards
USA Forward Racing (Suter-BMW CRT) 1m 52.795s
13. Michele Pirro
ITA Honda Gresini (FTR-Honda CRT) 1m 53.826s
14. Ivan Silva
ESP Avintia (FTR-Kawasaki CRT) 1m 54.177s
Official Aragon MotoGP records:
AUS Honda 1m 48.451s
Fastest race lap:
AUS Honda 1m 49.046s