Watch a modern MotoGP, Moto2 or World Superbike race with a casual fan and you can be certain there is one question they will ask you: “Why are they waving their legs about like that?” Many theories have been offered, often directly contradicting each other.

For example, several years ago, I suggested that the leg wave is entirely mental. Earlier this year, the Australian motorcycle coaching organization MotoDNA described the possible role which aerodynamics play, the exposed leg helping to create more drag. Much has been said, yet it seems impossible to settle the argument one way or another.

Asking the riders to explain does not help much. It is a question I and other journalists have asked of many different riders, including Valentino Rossi, Casey Stoner, Cal Crutchlow, and Dani Pedrosa. Their answers always boil down to the same thing: “It just feels natural,” they say. An interesting response, perhaps providing an insight into how deeply racers have internalized so much of the physical part of their riding, but not doing much to help explain the phenomenon.

To attempt to get to the bottom of this mystery, I turned to some of the best minds in the MotoGP paddock. For an explanation of the physics behind the leg wave, I asked Monster Tech 3 Yamaha crew chief and technical guru Guy Coulon, while for further insight from the point of view of an observer and ex-rider, I spoke to Wilco Zeelenberg, team manager of Jorge Lorenzo – the one current MotoGP rider who does not dangle his leg while riding.

Tuesday afternoon at Valencia saw groups of people huddled together up and down the paddock discussing what to do. With the weather having made the first day of testing difficult, and much, much worse forecast for Wednesday – half an inch or more of rain was forecast to fall during the seven hours of the test on Wednesday – several teams contemplated the prospect of packing up and heading elsewhere in search of a dry track.

In the end only Yamaha decided to go, heading off to Aragon, one of their nominated test tracks. In their wake, a string of journalists followed, hoping to get more of an idea of just how fast Valentino Rossi still is after his misadventure with Ducati, by being able to compare his times with those of Jorge Lorenzo’s. It turned out to be a waste of time. The rain fell in Aragon, Valentino Rossi did a single lap – out, and then straight back into the pits – and Jorge Lorenzo posted nine laps in the wet before crashing, and walking away unhurt.

If there is one subject that is getting mind-numbingly tedious to have to write about in motorcycle racing right now, it’s the weather. Almost every race this year has lost at least one session to difficult conditions, and we had hoped that the 2013 season might start off a little better. No such luck.

After a dry, clear night, the first rain showers arrived shortly before 10am, when the track was due to open for the test. By the time the track opened, enough rain had fallen to make it slick, greasy and extremely difficult to ride. That put an end to almost everyone’s carefully laid plans, leaving large groups of people wandering around and alternating between looking to the skies and carefully examining the track.

A few brave souls ventured out on to the track – including Valentino Rossi, at a few minutes after ten, the earliest he has ever taken to the track during testing since I’ve been following MotoGP, Rossi notoriously ill-disposed to mornings (as, I must admit, am I) – but for the most part, silence prevailed.

This was perhaps toughest on the TV commentators. Because of Rossi’s return to Yamaha, the first couple of hours of the test were streamed live on the MotoGP.com website, as well as broadcasted on both Italian and Spanish TV.

There was virtually nothing to show, though, except images of crowds milling in pit lane, riders wandering around chatting, some in leathers, some not, and endless repeats of slow-motion shots from the few bikes that had turned a lap in the morning, leaving commentators racking their brains for subjects to discuss, leading at one point to a surprisingly long discussion about fruit, and the riders who eat it.

Here’s one for the Rossi fans, the first photo of Valentino Rossi on-board the 1,000cc Yamaha YZR-M1 at the Valencia test (snagged by Monster Yamaha Tech 3 mechanic Steve Blackburn).

Apparently, the weather is being less than co-operative in Spain, with sprinkles of rain being reported, but that didn’t stop The Doctor from getting on-board “his” bike.

After the jump, there are 17 photos of Rossi’s maiden voyage back on the Yamaha YZR-M1 — all courtesy of photographer extraordinaire, Scott Jones.

The sense of expectation in the air at Valencia is wound so tight it hums. Tomorrow morning, some time after 10am, some of that expectation will start to dissipate as we get the first glimpses of answers that have preoccupied MotoGP fans for the past few months.

Two things we hope to see: a glimpse of the past and a glimpse of the future. After two long, hard years, the army of Valentino Rossi fans will be hoping to see something they haven’t since 2010, or maybe even 2009: a flowing, comfortable, aggressive Valentino Rossi at one with the machine underneath.

That was something he never showed while riding the Ducati, the figure in the Rossi replica helmet sitting on the Ducati always looking more like a club racer had sneaked into the back of the Ducati garage to take the bike out for a spin, terrifying himself in the process. Rossi looked stiff, awkward, uncomfortable, his back arched like a cat negotiating a dog-infested yard.

Another GP race weekend, and another weekend where the weather looms over the MotoGP paddock. Wasting Friday, and getting a reprieve on Saturday, the rain of Valencia was back for Sunday’s race, leaving a drying, but wet, course for the MotoGP riders to contend with on 200+ hp machines.

Casey Stoner’s last race, Dani Pedrosa’s last chance to have the most race wins, and Jorge Lorenzo’s final chapter to a flawless season, the script for the front-row starters was intriguing to say the least.

It all went out the window though, as we can confidently say that the following information contains no spoilers for those who have yet to see the race, since no human could possibly guess the outcome of the Valencian GP: a CRT bike lead the race for multiple laps, a Yamaha is on the podium, a world champion was lapped, and a satellite team finished both its bikes in the Top 5. Words can barely describe the race, but we will try after the jump.

A revolution is about to take place at Ducati, several reliable sources are reporting. The Bologna factory’s new owners Audi are pushing through wholesale changes, both MotoSprint and Moto.it are reporting, which include relieving Filippo Preziosi of his responsibility for Ducati’s MotoGP project and embarking on a parallel project to have Suter build a new chassis for the bike.

Who is to take the place of Preziosi at the head of Ducati Corse is unclear, but the name of Paolo Ciabatti, currently involved in World Superbikes and previously head of Ducati’s WSBK team, is being mentioned.

According to the reports in the Italian press, the removal of Preziosi is part of a wholesale reorganization of Ducati’s MotoGP project. The structure is to be altered to make it more ‘Japanese’ with the work divided up into separate divisions, and without tight central control of all aspects.

Suter has been commissioned by Audi to build a new chassis for the Ducati as part of a separate, parallel project to try to improve the bike.

The last of the 990cc pole records finally went at Valencia, along with the last record held by Valentino Rossi at any of the tracks currently on the calendar. Dani Pedrosa’s astonishing last lap was inch perfect, and put him 0.158 seconds faster than Rossi’s time, set in 2006 at the infamous season finale in which Rossi got a dismal start, then fell off trying to catch Nicky Hayden, handing the American the world championship in the process.

Pedrosa’s lap really was something special, though the Spaniard was not as impressed as the onlookers. He had had a few good laps in his career, he told the press conference, and this was definitely one of them. Pedrosa has looked ominous all weekend – actually, since Indianapolis – and if it were going to stay dry, then you would be hard put to think of anyone who could beat the Repsol Honda man.

Jorge Lorenzo is keen to try, and is fast all the way round the circuit to the final sector, but is losing a couple of tenths just in the acceleration out of the final corner and towards the line. The Hondas dominate there, good round the long left before the final corner – both Casey Stoner and Dani Pedrosa were hanging the rear out all round that turn, showing a hint of the old tire-smokin’ 990 days – but absolute missiles on acceleration.

That has been Lorenzo’s complaint all year, not sufficient acceleration and not the wheelie control which the Hondas appear to have. If Lorenzo arrives at the final corner with a Honda behind him, he will fear for his position.

With some cooperation from the weather at the track in Valencia, MotoGP enjoyed its last dry qualifying session of the season. Saturday’s afternoon session was a stark contrast to Friday’s Free Practice sessions, which had mostly been a wasted day for the GP riders. With nothing on the line for the Valencian GP, riders in MotoGP are mostly racing this weekend for pride and bragging rights.

Casey Stoner’s last race in MotoGP, the Australian is surely looking for a good result, though there are question marks regarding his ankle. His teammate Dani Pedrosa is also looking for a strong result in his home country, with the Spaniard now out of the Championship hunt, but looking to end what has been a stellar second-half of a season in the Repsol Honda squad.

The man to stop though is his once bitter rival Jorge Lorenzo, who will carry the #1 plate next year. For Lorenzo, Valencia is about winning the most races in the 2012 season, with him and Pedrosa tied at six a piece.

For many of the other riders, Sunday’s race marks the last time they will be in the premier class, with their current teams, or even on the same kind of race bike. Perhaps the biggest piece of anticipation for the race, is the post-season testing the follows it. But, first things first.

In an ideal world, championships are settled in a straight fight between the main contenders in the final race of the season. Unfortunately, the world we live in is far from ideal – as the ever-dwindling stock of prototype machines on the grid testifies – and so the last race of the year can be a bit of a formality. In 2012, with the champions in all three classes securing their titles during the flyaways, there is not much more at stake at Valencia. Except pride.

Given that pride is what motivates a motorcycle racer above all else, that means that there is every reason to hope for a real treat at Valencia on Sunday. This is the last race of the season, the last chance to prove your worth, to silence your doubters, to settle those scores before the long winter begins.

No need to be conservative here, no need to calculate the odds. You can take that chance, take a risk and crash out trying. At the last race of the season, you go all in, as Nicky Hayden’s leathers proclaimed at Valencia in 2006, when it looked like he might miss out on his first ever MotoGP title. And there is a lot of pride at stake.