Reigning champion Casey Stoner has lapped under two minutes on the final day's testing in Malaysia.
The Australian, who missed the opening day with a back problem, managed a best time of one minute 59.607 seconds.
"It's been a good test in general, we only managed two out of the three days unfortunately but the weather has been really good to us and we've been able to do what we planned," Stoner said.
Honda team-mate Dani Pedrosa was third, with Britain's Cal Crutchlow seventh.
"The day I missed hasn't affected us too much and we've managed to complete our testing programme," Stoner added.
"I think track conditions on the first day weren't that great anyway as the lap times were not so fast.
"So far it's been pretty positive, we'll just have to wait and see what we have for the next test and hopefully improve a little more."
Yamaha's Jorge Lorenzo was second fastest with nine-time world champion Valentino Rossi coming in fifth.
The capacity of MotoGP bikes has increased from 800cc to 1,000cc this year and Stoner admitted that he was enjoying the extra power available.
"Definitely more power is a little bit more fun. You can square the corners off a little bit more," said Stoner.
"I actually find more traction [with the 1,000cc bike]. I find this bike a little more stable."
"It felt better than ever to be back on a MotoGP bike," he said. "The finger is shorter and lighter - that's why I went faster!
"The 1,000cc bike is much more powerful so, if you make a mistake, you have enough power to recover the time on the exit. With the 800 you could not make any mistakes."
Testing ends on Thursday with another three-day session at Sepang beginning on 28 February. The 2012 season will officially start on 8 April in Qatar.
Selected MotoGP test times from Sepang:
1. Casey Stoner (Aus) Honda 1'59.607
2. Jorge Lorenzo (Spn) Yamaha 2'00.198
3. Dani Pedrosa (Spn) Repsol Honda 2'00.256
4. Ben Spies (USA) Yamaha 2'00.495
5. Valentino Rossi (Ita) Ducati 2'00.824
7. Cal Crutchlow (GB) Tech 3 Yamaha 2'01.108
15. Colin Edwards (USA) Forward Racing CRT 2'04.722