By alley - Feb 23, 2015, 6:31 AM ET

MotoGP: Rossi tops first day of second test

Valentino Rossi led the opening day of the second 2015 MotoGP test at Sepang on Monday, as alternate boiling temperatures and rainstorms hampered riders.

The morning's very hot weather – with track temperature nudging 140 degrees – left the circuit much more slippery than it had been for the opening test three weeks earlier. All the quickest times were set in the opening hours before the weather got warmer still, before conditions broke mid-afternoon when lightning and heavy rain arrived.

Rossi's early 2m00.414s lap for Yamaha therefore stood as the best of day one, putting him 0.129 seconds ahead of Dani Pedrosa's Honda. Yamaha brought a major gearbox upgrade to this test as it tries to reduce the advantage Honda's seamless shift system had last year.

Espargaro brothers Pol and Aleix were next up, as the latter showed strong pace on the new Suzuki, although his day was also interrupted by a crash.

Rookie Maverick Vinales also got Suzuki into the top 10 as he took ninth on the sister bike.

Jorge Lorenzo and Marc Marquez made low-key starts in fifth and sixth, ahead of Cal Crutchlow and Bradley Smith.

Ducati's eagerly awaited new GP15 bike made its debut, although Andrea Dovizioso and Andrea Iannone also had interim 2014 versions available too. Both set their best times on the GP14.3 as tentative work began on the bike Ducati is counting on to end its win drought.

The test continues for three more days, with Thursday reserved for Michelin tyre testing ahead of its 2016 return. That session will be the factory MotoGP riders' first chance to try the new rubber, as Michelin running has been restricted to test riders so far.

Pos	Rider	Bike	Team	Time	Gap	Laps
1	Valentino Rossi	Yamaha	Yamaha	2m 00.414s	-	54
2	Daniel Pedrosa	Honda	Honda	2m 00.543s	0.129s	52
3	Pol Espargaro	Yamaha	Tech 3	2m 00.876s	0.462s	45
4	Aleix Espargaro	Suzuki	Suzuki	2m 01.055s	0.641s	39
5	Jorge Lorenzo	Yamaha	Yamaha	2m 01.162s	0.748s	51
6	Marc Marquez	Honda	Honda	2m 01.190s	0.776s	43
7	Cal Crutchlow	Honda	LCR	2m 01.222s	0.808s	43
8	Bradley Smith	Yamaha	Tech 3	2m 01.241s	0.827s	51
9	Maverick Vinales	Suzuki	Suzuki	2m 01.317s	0.903s	50
10	Andrea Dovizioso	Ducati	Ducati	2m 01.355s	0.941s	23
11	Scott Redding	Honda	Marc VDS	2m 01.592s	1.178s	52
12	Alvaro Bautista	Aprilia	Aprilia Gresini	2m 01.740s	1.326s	51
13	Hector Barbera	Ducati	Avintia Racing	2m 01.926s	1.512s	39
14	Nicky Hayden	Honda	Aspar	2m 02.062s	1.648s	41
15	Andrea Iannone	Ducati	Ducati	2m 02.142s	1.728s	30
16	Danilo Petrucci	Ducati	Pramac Racing	2m 02.225s	1.811s	35
17	Karel Abraham	Honda	AB Motoracing	2m 02.394s	1.980s	28
18	Stefan Bradl	Forward Yamaha	Forward Racing	2m 02.410s	1.996s	42
19	Yonny Hernandez	Ducati	Pramac Racing	2m 02.606s	2.192s	29
20	Eugene Laverty	Honda	Aspar	2m 02.730s	2.316s	45
21	Mike Di Meglio	Ducati	Avintia Racing	2m 02.941s	2.527s	33
22	Jack Miller	Honda	LCR	2m 03.006s	2.592s	35
23	Michele Pirro	Ducati	Ducati	2m 03.105s	2.691s	35
24	Loris Baz	Forward Yamaha	Forward Racing	2m 03.316s	2.902s	37
25	Katsuyuki Nakasuga	Yamaha	Yamaha	2m 03.337s	2.923s	43
26	Alex de Angelis	ART/Aprilia	IodaRacing Project	2m 03.966s	3.552s	45
27	Marco Melandri	Aprilia	Aprilia Gresini	2m 04.000s	3.586s	42