Repsol Honda, LCR Honda and the Factory Yamaha team began a private three-day test at the new Circuit of the Americas in Austin, Texas on Tuesday.
The test marks the first ever laps for full time MotoGP competitors at the circuit, American CRT wild-cards having been the only previous grand prix bikes to test at the track.
Testing concludes on Thursday evening, but Yamaha will not test on the final day.
The last official MotoGP test will be held at Jerez, Spain from March 23-25.
COTA, which impressed on its F1 debut late last year, will host its first MotoGP race from April 19-21, as round two of this year's world championship.
for pictures from the test...
1. Marc Marquez
ESP Repsol Honda (RC213V) 2m 3.853s
2. Dani Pedrosa
ESP Repsol Honda (RC213V) 2m 3.976s
3. Jorge Lorenzo
ESP Yamaha Factory (YZR-M1) 2m 4.351s
4. Stefan Bradl
GER LCR Honda (RC213V) 2m 4.640s
5. Valentino Rossi
ITA Yamaha Factory (YZR-M1) 2m 4.960s
6. Blake Young
USA Attack Performance (Attack-Kawasaki CRT) 2m 13.641s
7. Michael Barnes
USA GPTech (BCL-Suzuki CRT) 2m 13.993w
Fastest Day 1 time:
ESP Repsol Honda 2m 4.619s