Testing began at 10am and concludes at 6pm. However storm clouds began gathering around midday, with heavy rain starting to fall at 2pm meaning the day could be effectively over.
All twelve manufacturer riders are again present for the three-day test, plus the Forward Racing and BQR 'Claiming Rule Teams'.
Factory Ducati rider Nicky Hayden and Tech 3 Yamaha's Andrea Dovizioso will be hoping their healing injuries will allow for greater track time than at the first test.
However Karel Abraham (Cardion AB) is struggling with a back injury sustained at the recent private Jerez test and looks set to miss day one.
The second Sepang test finishes on Thursday evening, after which only one more official test (at Jerez) will remain before the start of the racing season.
for pictures from the test...
1. Casey Stoner
AUS Repsol Honda 2m 1.761s
2. Dani Pedrosa
ESP Repsol Honda 2m 2.005s
3. Jorge Lorenzo
ESP Yamaha Factory Racing 2m 2.436s
4. Ben Spies
USA Yamaha Factory Racing 2m 2.819s
5. Alvaro Bautista
ESP San Carlo Honda Gresini 2m 2.959s
6. Nicky Hayden
USA Ducati Team 2m 3.132s
7. Cal Crutchlow
GBR Monster Yamaha Tech 3 2m 3.213s
8. Valentino Rossi
ITA Ducati Team 2m 3.245s
9. Hector Barbera
ESP Pramac Racing 2m 3.612s
10. Stefan Bradl
GER LCR Honda 2m 3.820s
11. Andrea Dovizioso
ITA Monster Yamaha Tech 3 2m 3.830s
12. Franco Battaini
ITA Ducati Test Rider 2m 5.563s
13. Colin Edwards
USA Forward Racing (Suter-BMW CRT) 2m 5.686s
14. Ivan Silva
ESP Avintia (FTR-Kawasaki CRT) 2m 8.479s
15. Yonny Hernández
COL Avintia (FTR-Kawasaki CRT) 2m 8.767s
Fastest Sepang I test times (Feb 2):
AUS Honda 1m 59.607s
ESP Yamaha 2m 0.198s
ITA Ducati 2m 0.824s
USA Suter 2m 4.722s
ESP FTR 2m 8.225s
Official Sepang MotoGP lap records:
ITA Yamaha 2m 0.518s
Fastest race lap:
AUS Ducati 2m 2.108s