By Matt Roberts
BBC MotoGP reporter
Rossi gave his new Ducati a run-out at the Ricardo Tormo track near Valencia
No sooner had the smoke cleared from the fireworks that marked the end of the 2010 season at Valencia last Sunday than the thunder of 800cc motorcycles was filling the air once again.
Pre-season testing for 2011 began on Tuesday, with
seven-time world champion Valentino Rossi making his eagerly anticipated debut on board the Ducati Desmosedici,
Australian Casey Stoner taking his bow on the factory Honda RC212V and Britain's Cal Crutchlow riding the Yamaha YZR-M1 for the first time in public.
With television rights holders Dorna offering a live feed of the opening two hours of the test, Rossi's historic first ride had threatened to turn into a damp squib as the circuit was blanketed by grey clouds and light drizzle, but factory test rider Franco Battaini gamely played chief taster to the king, completing a handful of laps on wet tyres and helping to create a dry line as the sun broke through.
At precisely 12.23pm local time, seven minutes before the television feed was due to be cut, Rossi's trademark luminous yellow emerged from the Italian garage, flecked across black leathers and a carbon fibre paint job on the brand new GP11 machine.
A lap of one minute 33.8 seconds, the tenth fastest of the first day, had journalists rubbing their hands but further down pit lane another debutant was quietly making his mark.
Stoner had kept a watching brief for much of the morning, leaning on the pit wall in an unbranded puffer jacket and laughing and joking with other members of the paddock, but he wasted little time adapting to his new steed when he did take to the track for just 44 laps in the afternoon.
Over a second faster than Rossi, Stoner's lap of 1:32 was bettered only by Sunday's race winner Jorge Lorenzo as the Australian quickly got to grips with the 2010 version of the RC212V.
On the Wednesday Stoner got his first taste of the 2011 machine and shaved off another 0.7 seconds to lap just two tenths outside the time that gave him pole position on the Ducati at the weekend, finishing as the fastest rider of the day although still a fraction outside Lorenzo's best from the opening day of the test.
Stoner made a strong impression when he took to the track
Whilst the machines Stoner rode at Valencia featured a white livery with Australian stars and a kangaroo design down the side, he will be in full Repsol Honda colours in 2011 - as will Dani Pedrosa and Andrea Dovizioso.
Honda are also planning to prepare a fourth factory-spec machine for Marco Simoncelli, who has emerged as a serious podium contender in the final few rounds of 2010.
Back at Ducati the engineers were impressed by the feedback given by Rossi although they admitted they have a lot of work to do to adapt the GP11 to his riding style after the Italian ended up 15th overall, only 0.032 seconds ahead of rookie Karel Abraham, who made a surprisingly good start to life on the satellite Desmosedici.
Development back at the Bologna factory will focus on front end feel, with Rossi having a much less aggressive approach to riding than previous incumbent Stoner, and will be carried forward with the 'big bang' version of the engine as opposed to the 'screamer' that was also available at the Valencia test.
Whilst Abraham, who took his first Moto2 win on his final appearance in the class last Sunday, raised more than a few eyebrows with his pace Crutchlow also impressed on the satellite Yamaha.
Crutchlow completed 133 laps over the two days, regularly dipping into the 1:33, which was race pace last Sunday, and he finished up thirteenth overall - just over a tenth outside his new team-mate Colin Edwards.
Over in the factory Yamaha garage 2010 world champion Lorenzo split his riding time between the 2011 prototype YZR-M1 and an updated version of his 2010 machine, whereas Ben Spies was keen to work solely on the new version, having enjoyed riding it in the Brno test back in August. Whilst Lorenzo set the pace, his new factory team-mate was just three tenths of a second behind, finishing the test third fastest overall.
Before the MotoGP riders took to the track on Tuesday there was an opportunity for the Moto2 boys to shake off their hangovers with a few hours on track on Monday.
Bradley Smith made his debut in the intermediate class riding the Tech3 bike, assisted by his new crew chief, the experienced Tom Jojic, who worked with Hiroshi Aoyama in MotoGP this year.
Fresh off the back of his first 125cc win of the season the previous day, Smith knocked out a marathon 90 laps - more than anybody else on track - and shrugged off complaints about the handling of the French bike, which had been heavily criticised by this year's riders Yuki Takahasahi and Rafele de Rosa.
"They have been complaining all year about chatter but Tom came up with some ideas that sorted it out almost straight away," Smith reflected. "It has been an amazing 24 hours for me. Today was all about getting confident and comfortable on the bike and learning as much as I can. Obviously we've got a long way to go but it feels like we've done so much already in such a short space of time."
Scott Redding was also on hand at the test, completing a few laps on his 2010 race bike before switching to a revised chassis that will form the basis of the 2011 Suter MMX. The teenager will be joined in the Marc VDS team by Mika Kallio next year, with the Moto2 class shaping up to be even more competitive than this year.
World Supersport champion Kenan Sofuoglu signed with the Technomag CIP team at Valencia whilst Aleix Espargaro drops down from MotoGP and his brother Pol moves up from the 125cc class alongside newly-crowned World champion Marc Marquez and Smith.
In the MotoGP class it looks like the four 'aliens' could become five as Ben Spies consolidates his place amongst the factory elite. In their minds the racing has already started. For us the countdown to Qatar starts here.