The departure of Bridgestone and the arrival of Michelin as official tire supplier to MotoGP is an extremely delicate operation, in terms of marketing, tire development, and motorcycle set up. Bridgestone have paid a lot of money for the exclusive rights to MotoGP branding with their tires for 2015; Michelin have done the same for the rights from 2016 onwards. Neither company wants to tarnish their brand or see the value of their investment diminished, either by rider comments expressing a preference one way or another, or by lap time comparisons showing either firm up.

This posed problems for the Michelin test, held on the fourth day of the Sepang MotoGP test. After the factory test riders had tried the Michelins at the first Sepang test, it was the turn of the MotoGP regulars. To avoid any comments which might favor one factory or another, Bridgestone imposed a blanket ban on riders or team members speaking to the media after the test. All Bridgestone branding was removed from bikes and leathers, and no visible Michelin branding was allowed, even down to the manufacturer's logo on the tire sidewalls. With major money on the line, the PR gagging order was enforced rigidly, and observed religiously. No official times were released, nor made unofficially available by the teams. A range of times have seeped out from journalists present, but given that only a few laps were timed by a few people out of practice with using a stopwatch (or its modern equivalent, the smartphone), those times can be taken as guidelines only.

Perhaps the biggest problem was posed by the requirements of tire testing. The riders have just completed three days of testing, building speed and confidence on their 2015 bikes with the latest generation of Bridgestones. They have put in a lot of laps in extreme heat, and are running out of reserves of energy, despite their almost superhuman fitness levels. Their minds and muscle memory is completely attuned to the Bridgestones, so putting them onto a different tire with different characteristics poses a major risk. The riders are focused on pushing hard, and expecting a particular feel from the tires, front and rear. It is potentially a recipe for disaster.

Take a glance at the timesheet after the final day and it is easy to draw some simple conclusions from of second Sepang MotoGP test. Marc Márquez reigns supreme, with Jorge Lorenzo is the only rider to get anywhere near to him. Cal Crutchlow has improved, but at the moment is only fast over a single lap. The Ducati Desmosedici GP15 is fast, but only in the hands of Andrea Iannone. Valentino Rossi and Dani Pedrosa have their work cut out if they are to match their teammates. Bradley Smith has surpassed his teammate, Pol Espargaro. Suzuki is close, but not quite close enough, while Aprilia are hopelessly lost.

As attractive as those conclusions are, the underlying truth is a lot more complex. Testing is exactly that, testing, and everyone is on different programs, trying different things at different times of the day. Or as Dani Pedrosa succinctly put it, when asked if he was trying out a new strategy for qualifying during the test, "we were just trying. That's why we are here." Marc Márquez was undeniably faster than the rest of the field, and his race simulation was undeniably faster than anyone else's. But just comparing the times does not provide the whole picture.

Márquez' race simulation was fearsome to behold. 19 laps at an average of 2:00.760, just one shy of full race distance. 16 laps of 2:00, just three of 2:01. While it is impossible to know how fast his out lap was – the analysis timesheets available only show the full lap times, and no partials, and Márquez embarked on his race simulation after spending 15 minutes in the pits – that pace would have seen him beat his own race time from last year by some 25 seconds. That is seriously fast.

Press releases at the end of the second test at Sepang:

While the focus of most testing is on the rider who goes fastest - that, after all, is the point of motorcycle racing - only looking at the best times does not tell the full story. If the aim of testing is to improve, then measuring improvement can reveal the shift in power, and give hints of the shape of things to come.

Comparing times between the Sepang 1 and Sepang 2 tests show Hector Barbera as the man who has got the most out of the two tests. The Avintia Ducati rider has already shown solid pace, ending the test as 8th overall on the Open Class GP14, and ahead of Andrea Dovizioso on the factory Ducati GP15. Barbera is clearly highly motivated, and with a much more competitive bike, capable of some interesting results. After the two Sepang tests, he has staked his claim as the favorite to win the Open class in 2015, if he can translate his one-lap pace into the race.

Marc Marquez finished on top of the timesheets at the second test at Sepang, posting a fast lap early and then switching his focus to race set up. The Repsol Honda rider completed a punishing test, grinding out 73 laps in the blistering heat of Sepang, 12 more than any other rider. Marquez finished with a race simulation in the final hour of the test. Jorge Lorenzo leaves Sepang as 2nd fastest, the Movistar Yamaha rider satisfied with the work done so far, and the gap to Marquez three tenths of a second. Cal Crutchlow surprised many with a fast lap in the morning, made despite braking problems to take third slot, ahead of Andrea Iannone on the Ducati GP15. Valentino Rossi was 5th fastest, and Dani Pedrosa was one of the few riders to improve their times at the end of the day, finally cracking the two minute barrier.

The combined timesheet looks very similar to the timesheet from Wednesday, almost everyone improving their lap time on the final day. Only Andrea Dovizioso, Loris Baz and Yamaha test rider Katsuaki Nakagama were faster yesterday, the difference for Dovzioso meaning he climbs up to 9th in the combined standings.

With temperatures hotter again on Wednesday, a lot of riders got their fast laps in early on the last day of the official test, at least on Bridgestones. Marc Marquez was, unsurprisingly, the fastest, his quick lap impressive, but unable to match the record time he set at the first Sepang test. Jorge Lorenzo took 2nd, and did manage to beat his best time from Sepang 1, perhaps a sign of the progress Yamaha have made. Cal Crutchlow was 3rd quickest, and nearly a second faster than his best time at the first, though the LCR Honda rider was struggling with brake problems similar to those suffered by Marc Marquez on Monday.

Andrea Iannone was the fastest of the Ducatis, taking 4th spot aehad of Valentino Rossi, while Bradley Smith improved to takes 6th, and the last rider under the two minute mark for the moment. Dani Pedrosa has the 7th fastest time so far, ahead of Hector Barbera on the Open class Ducati, an impressive feat from the Avintia rider, though he found a wheel to follow to set the time. Aleix Espargaro is in 9th, while Andrea Dovizioso rounds out the top ten on the other factory Ducati. With temperatures starting to cool a little, riders will likely put in another attempt to improve their times at the end of the day, when track conditions are a little more conducive to fast laps.

Times at 4pm:

After the excitement and confusion of the first day of testing at Sepang, some semblance of normality returned on Tuesday. Cooler temperatures and more stable weather meant that riders had much more time to do work on track, the heat and humidity not quite as oppressive as they had been the previous day. The excitement over new bikes and gearboxes had also subsided, and the hard grind continued.

If Tuesday is representative of the normal state of play in MotoGP, then it seems like there are already two favorites for the title emerging from the pack, though margins are slim indeed. Marc Márquez and Jorge Lorenzo were the only two riders to crack the two minute barrier, posting fast times early on in the day, then getting back to work on 2015. Nobody else got near, with the exception of Andrea Iannone, who piled in a quick lap at the end of the day to fall just short of two minutes, the Ducati GP15 quickly proving its worth.

Marc Márquez was perhaps the most relieved rider. After losing a day due to untraceable braking issues, things were back to normal as soon as he hit the track on Tuesday. Márquez was cagey about the cause of the brake issue, joking that he did not want to reveal the secret to his rivals, in case they too suffered the issue. The Repsol Honda rider spent the day focusing on electronics and engine management, working hard to make up for lost time. That left him still with work to do on Wednesday, when the team will turn their attention to the chassis he is supposed to be testing. So far, Márquez has been sticking with the chassis he used at the last Sepang test, but Honda also have a chassis with 'something for the rear'. Whether that is in the frame, swing arm, shock mount, or linkage is not clear.

Press releases from the MotoGP teams after the second day of testing at Sepang:

Marc Marquez has ended the second day of testing at Sepang on top of the timesheets, after cracking under the two minute barrier in the relative cool of the morning. With temperatures a little lower than yesterday, times were quicker, with both Marquez and Jorge Lorenzo managing to get under the two minute mark. The Ducati GP15 performed well, the two Andreas taking 3rd and 4th spots. Dovizioso set his time in the morning, while Iannone leapt ahead of his teammate in the last few minutes with lap that got him to within two tenths of Marc Marquez.

Dani Pedrosa took 5th spot, ahead of Valentino Rossi, the Honda and Yamaha riders posting fast times at the start of the day, and concentrating on testing for the rest of the day. Bradley Smith and Cal Crutchlow posted their fast times at the end of the session, Smith having moved up t 7th from 13th spot, while Crutchlow had already set a quick lap in the morning. Aleix Espargaro set the 9th quickest time in the morning, the Suzuki proving to be quick, and beat his brother, Tech 3 Yamaha rider Pol, into 10th.

Marc Marquez tops the timesheets with a few hours to go on the second day of the Sepang test, the Spaniard clearly over his braking problems from yesterday. Jorge Lorenzo is also better than yesterday, the Movistar Yamaha man looking pale and drawn on the first day and suffering from jet lag. Lorenzo has been pounding in fast laps andi is just behind Marquez' time. 

The Ducati Desmosedici GP15 may be new, but it is showing a lot of promise, Andrea Dovizioso posting a very quick time on the GP15 to take 3rd spot, just ahead of Dani Pedros and Valentino Rossi. Aleix Espargaro has confirmed the strength of the Suzuki, Espargaro being just a tenth slower than Rossi, but up among the front runners, with Andrea Iannone right behind him. Cal Crutchlow follows, having closed the gap considerably on the LCR Honda, two thirds of a second off Marquez, but just a couple of tenths behind Pedrosa. Pol Espargaro is currently 9th on the Tech 3 Yamaha, while Danilo Petrucci is a highly creditable 10th, on the older version of the GP14.

Times at 4pm:

If the purpose of testing in Sepang is to ensure that as little time as possible is lost to the weather, then the first day of the MotoGP test fell well short of its objectives. The Malaysian circuit sweltered under oppressive tropical heat all day, rendering most of the day of little use for testing. With track temperatures approaching 60°C in the early afternoon, the grip disappeared, and the heat made riding a MotoGP bike a punishing affair. Then, just as the riders returned to the track as the air began to cool, a tropical thunderstorm washed the track out, with lightning causing the session to be red-flagged for a while. It was not a day in which the teams could get an awful lot done.

That was a shame, as they had an awful lot to do. Ducati had brought the GP15 for its on-track debut, Yamaha had its fully seamless gearbox, Suzuki had unleashed a few more horses from its GSX-RR, and Aprilia had a stack of chassis and electronics solutions to test on track. With on a couple of hours of productive track time, much was left untested.

The biggest question mark at Sepang would be how the Ducati GP15 would work. Would the new bike built under the direction finally cure the understeer which has plagued all previous iterations of the Desmosedici? Andrea Dovizioso had that question answered in the first two corners, he told reporters. When he went to turn the bike in, he found himself on the inside of the kerbs. All of the effort the previous bike required was gone. The GP15 turns, which was exactly what was required of it. "I'm really happy," Dovizioso said. "Now we can work in a normal way. When the bike turns like the competitor, I think you can adapt the bike to your riding style."

Press releases from the MotoGP teams after the first day of testing at Sepang:

Valentino Rossi has topped the timesheets on the first day of the second Sepang MotoGP test. In a day marked by the weather, the Movistar Yamaha rider set a quick lap in the morning, before the extreme heat became too oppressive, to finish ahead of Dani Pedrosa on the Repsol Honda and Pol Espargaro on the Tech 3 Yamaha.

The weather played a major role all day at Sepang. The day started hot, the heat increasing towards the afternoon, causing the track to be greasy and prompting complaints of a lack of grip. That left a lot of riders stuck in their pit boxes to sit out the hottest part of the day, in the hope of doing more work at the end of the day. The weather gods were not inclined to be merciful, however, and heavy rain started falling around 4:30pm, just as riders were taking to the track once again. Rain and thunderstorms played havoc with the rest of the day, a couple of lightning strikes causing the session to be red-flagged, then restarted.

The second test at Sepang has gotten underway in sweltering conditions, the heat much greater than at the first test two weeks ago, making the track greasier and times slower. The heat has limited action, with times set during the morning, and riders taking a long break for lunch. Valentino Rossi is currently fastest, the Movistar Yamaha man leading the Repsol Honda of Dani Pedrosa by just over a tenth of a second. In third is Aleix Espargaro, the Suzuki man very quick out of the gate on the bike.

The plan for Ducati changed at the last minute, meaning that the Ducati riders took the GP15 out today, instead of waiting until Tuesday, as was the original plan. Andrea Dovizioso's fourth quickest time was set on the GP14.3, however, the bike Ducati brought to the Sepang 1 test, while Iannone has been doing runs on the GP15, his quickest time set on the new bike.

Times at 4:15pm:

The engineers have had two weeks to pore over the data from the first MotoGP test at Sepang, identify problems, analyze strengths, and find more ways to go faster. Their analyses have been translated into designs, into new parts, into yet more software, ready to put their theories into practice. On Monday morning, at 10am Malaysian time, the MotoGP riders get to try out all of the new parts and ideas thought up by their factories and teams in search of a few more fractions of a second.

The eyes of the world will not be on what the engineers did between Sepang 1 and Sepang 2, however. Attention will be focused on Yamaha and Ducati, who will be testing hardware which has been a long time coming. Yamaha is bringing its fully seamless gearbox to the Sepang 2 test, and Ducati will roll out its Desmosedici GP15 for the first time. Both could make a significant impact.

In the short term, Yamaha's seamless gearbox is likely to be the most important development. It has not been officially confirmed that Yamaha will be bringing the full seamless gearbox (seamless in both upshifts and downshifts). Officially, people wearing Yamaha shirts will tell you that nothing has been decided yet, but well-informed gossip says that the seamless gearbox will be there, for both Valentino Rossi and Jorge Lorenzo. Yamaha's test riders have been using it for several months now, Colin Edwards having tested it extensively at the end of last year.