Stoner tops opening day of Sepang MotoGP test

Ducati's Casey Stoner led the times in a rain-interrupted opening day of MotoGP testing at Sepang.

The two-time world champion completed 32 laps with a best time of 1m59.680s, narrowly edging out teammate Andrea Dovizisio's 1m59.797s as the pair worked to gather data on the new exhaust system that heads the list of updates that the Italian manufacturer brought to Malaysia.

Just behind them was Maverick Vinales, who completed 54 laps on his new Movistar Yamaha machine with a best of 2m00.129s before the heavens opened. The team opted against trying any new parts on the opening day, and Vinales' teammate Valentino Rossi finished up 1.0s down on Stoner's time and eighth-fastest.

Alvaro Bautista led the session early on and finished the day fourth overall on the Aspar Ducati, distinguishing himself further by taking the opportunity to squeeze in some wet weather running when the rain began to fall.

Rounding out the top five was Team Suzuki Ecstar's Andrea Iannone, just ahead of leading Honda rider Cal Crutchlow. Reigning world champion Marc Marquez finished the day ninth-fastest, 0.2s ahead of Repsol Honda teammate Dani Pedrosa. Like Ducati, Honda arrived with a new exhaust system.

Elsewhere, KTM's preparations for a full-time MotoGP campaign continued, with Pol Espargaro producing a 2m01.338s and Bradley Smith a 2m03.033s on their tubular steel-framed RC16s.