Marc Marquez headed the times as the MotoGP field stayed on at Brno for a post-race test day on Monday.
The day after his dominant 2014 streak ended with a fourth-place finish in the Czech Grand Prix, Marquez was first out of the pitlane on his Honda and set the initial pace.
He produced his eventual benchmark of 1m55.411s in the final hour, when the track had dried after a heavy rain shower that convinced some teams to pack up.
Jorge Lorenzo spent much of the day in front between Marquez's quick laps, ending the test 0.155 seconds behind his countryman.
Both Honda and Yamaha tried various elements of their 2015 packages with their factory riders through the day.
Dani Pedrosa was third for Honda, just ahead of a Yamaha quartet - with Aleix Espargaro's Forward version leading works rider Valentino Rossi and Tech 3 duo Bradley Smith and Pol Espargaro.
Nine-time 500cc/MotoGP race winner Loris Capirossi made a brief comeback for the test.
Now working as the series' safety advisor, he accepted invitations to try Forward's Yamaha and FTR-framed bikes as well as the Cardion Honda, and was pleased to be within four seconds of the pace on his first MotoGP run in two years.
Another unusual face in action was American sometime Moto2 rider Kenny Noyes, who had an outing with Avintia.
Current Moto2 frontrunner Dominique Aegerter should have been testing with Forward, but after Alex de Angelis struggled in his first race back replacing Colin Edwards last weekend, the team decided to give the Italian more mileage instead.
Leon Camier continued with Aspar in Nicky Hayden's absence.
Camier, who was unhurt in an early crash, is waiting to hear for certain if he can stay on for Silverstone, amid rumours that Hayden needs more time to recover from wrist surgery.
Ducati only fielded Yonny Hernandez and Michele Pirro on Monday as its factory racers will instead be carrying out a private test at Misano later this month.
Pos Rider Bike Time Gap Laps
1. Marc Marquez Honda 1m55.411s 65
2. Jorge Lorenzo Yamaha 1m55.566s +0.155s 52
3. Dani Pedrosa Honda 1m56.014s +0.603s 38
4. Aleix Espargaro Forward Yamaha 1m56.173s +0.762s 52
5. Valentino Rossi Yamaha 1m56.446s +1.035s 63
6. Bradley Smith Tech 3 Yamaha 1m56.451s +1.040s 60
7. Pol Espargaro Tech 3 Yamaha 1m56.502s +1.091s 61
8. Stefan Bradl LCR Honda 1m56.519s +1.108s 51
9. Alvaro Bautista Gresini Honda 1m56.806s +1.395s 66
10. Yonny Hernandez Pramac Ducati 1m56.988s +1.577s 43
11. Michele Pirro Ducati 1m57.375s +1.964s 71
12. Karel Abraham Cardion Honda 1m57.659s +2.248s 44
13. Scott Redding Gresini Honda 1m57.772s +2.361s 56
14. Leon Camier Aspar Honda 1m58.179s +2.768s 36
15. Hiroshi Aoyama Aspar Honda 1m58.327s +2.916s 41
16. Alex de Angelis Forward Yamaha 1m58.759s +3.348s 57
17. Mike di Meglio Avintia FTR-Kawasaki 1m59.662s +4.251s 43
18. Loris Capirossi 2m00.649s +5.238s 6
19. Kenny Noyes Avintia FTR-Kawasaki 2m03.442s +8.031s 23