Repsol Honda's Dani Pedrosa set the fastest time during the Thursday's second practice session for the Dutch MotoGP at Assen.
Pedrosa's time of 1m 33.450s was 0.139s faster than that of his team-mate Marc Marquez, whose time 1m 33.589s on the RC213V was the pace-setter in the initial stages of the session.
Reigning champion Marquez has decided to use the HRC's 2014 chassis with this year's swingarm in an attempt to improve the RC213V's handling in corners, which has been a major issue for the Spaniard so far this season.
Championship leader Valentino Rossi, who was the fastest in first practice earlier on Thursday, finished the session in third, some 0.202s down on Pedrosa.
Andrea Iannone on the Ducati briefly had the fastest time but by the end of the session his time of 1m 33.699s was only good enough for fourth.
The top six was rounded out by Cal Crutchlow on the CWM LCR Honda and Jorge Lorenzo on the sister Yamaha.
Lorenzo is chasing a fifth consecutive victory this weekend but his time of 1m 33.741s left him 0.291s down on Pedrosa.
Andrea Dovizioso on the second Ducati finished in seventh, just ahead of Suzuki's Aleix Espargaro, Danilo Petrucci on the Pramac Ducati GP14, with Maverick Vinales on the second Suzuki rounding out the top 10.
Monster Yamaha Tech 3 riders Pol Espargaro and Bradley Smith were separated by Pramac Ducat rider Yonny Hernandez, while Scott Redding on the EG 0,0 Marc VDS Honda in 14th, albeit 1.193s behind the factory Honda of Pedrosa.
The top 15 was completed by Stefan Bradl on the Forward Yamaha, with Aspar Honda pair Eugene Laverty and Nicky Hayden bringing up the rear.
1. Dani Pedrosa ESP Repsol Honda Team (RC213V) 1m 33.450s [Lap 18/20]
2. Marc Marquez ESP Repsol Honda Team (RC213V) 1m 33.589s 0.139s [5/19]
3. Valentino Rossi ITA Movistar Yamaha MotoGP (YZR-M1) 1m 33.652s 0.202s [20/21]
4. Andrea Iannone ITA Ducati Team (Desmosedici GP15) 1m 33.699s 0.249s [18/19]
5. Cal Crutchlow GBR CWM LCR Honda (RC213V) 1m 33.734s 0.284s [16/19]
6. Jorge Lorenzo ESP Movistar Yamaha MotoGP (YZR-M1) 1m 33.741s 0.291s [16/17]
7. Andrea Dovizioso ITA Ducati Team (Desmosedici GP15) 1m 33.844s 0.394s [19/19]
8. Aleix Espargaro ESP Team Suzuki Ecstar (GSX-RR) 1m 33.857s 0.407s [18/18]
9. Danilo Petrucci ITA Octo Pramac Racing (Desmosedici GP14.1) 1m 34.133s 0.683s [19/20]
10. Maverick Viñales ESP Team Suzuki Ecstar (GSX-RR)* 1m 34.232s 0.782s [18/19]
11. Pol Espargaro ESP Monster Yamaha Tech 3 (YZR-M1) 1m 34.321s 0.871s [14/19]
12. Yonny Hernandez COL Octo Pramac Racing (Desmosedici GP14.2) 1m 34.406s 0.956s [18/20]
13. Bradley Smith GBR Monster Yamaha Tech 3 (YZR-M1) 1m 34.627s 1.177s [19/23]
14. Scott Redding GBR Estrella Galicia 0,0 Marc VDS (RC213V) 1m 34.643s 1.193s [20/20]
15. Stefan Bradl GER Athina Forward Racing (Forward Yamaha) 1m 34.664s 1.214s [18/20]
16. Loris Baz FRA Athina Forward Racing (Forward Yamaha)* 1m 34.897s 1.447s [13/18]
17. Eugene Laverty IRL Aspar MotoGP Team (RC213V-RS)* 1m 35.047s 1.597s [16/21]
18. Nicky Hayden USA Aspar MotoGP Team (RC213V-RS) 1m 35.149s 1.699s [15/19]
19. Alvaro Bautista ESP Factory Aprilia Gresini (RS-GP) 1m 35.489s 2.039s [15/18]
20. Hector Barbera ESP Avintia Racing (Desmosedici GP14 Open) 1m 35.538s 2.088s [20/20]
21. Jack Miller AUS CWM LCR Honda (RC213V-RS)* 1m 35.646s 2.196s [14/19]
22. Mike Di Meglio FRA Avintia Racing (Desmosedici GP14 Open) 1m 35.663s 2.213s [15/17]
23. Alex De Angelis RSM E-Motion IodaRacing (ART) 1m 36.869s 3.419s [12/21]
24. Marco Melandri ITA Factory Aprilia Gresini (RS-GP) 1m 37.225s 3.775s [17/17]