Why Yamaha had its worst season in a decade

November 15, 2016. Maverick Vinales tops the opening day of post-season MotoGP testing at Valencia on his debut with his new Yamaha team, recording a best time of 1m30.930s.

November 14, 2017. Vinales again tops the first day of Valencia testing for Yamaha with a 1m30.189s.

And the intervening 12 months? A rollercoaster of a season that started in the best possible way - three wins in the first five races and a comfortable points lead - and ended in confusion and dismay.

That was Vinales' side of the garage, but things weren't much better for Valentino Rossi. A single win at Assen was all 'The Doctor' had to show for a largely forgettable season that was interrupted by a broken leg, which forced him to skip his home race at Misano.

The net result for the factory Yamaha squad was its worst combined points haul since 2012, the year before Rossi rejoined the team after his failed two-year Ducati experiment, while it failed to breach the top two of the riders' standings for the first time since '07.

That season was an unusual one, as it was the first year of MotoGP's unpopular switch to 800cc machines (it reverted to 1000cc bikes in 2012). Rossi and Yamaha found themselves on the wrong side of a tyre war, as Bridgestone-shod Ducati stole a march on the rest and Casey Stoner scorched to glory.

By contrast, 2017 featured no major technical changes from the previous year, with most teams and riders having sussed the tricky Michelin tyres that were introduced in '16.

So, how did Yamaha get it so badly wrong in 2017?

The 2016 Yamaha M1 was widely recognised as being the class of the field, and it was largely riding errors from Rossi and Jorge Lorenzo that allowed Marc Marquez to clinch the title for Honda instead.

But the riders still had their complaints at the end of 2016, namely a lack of top-end speed and front-end feeling. These were the issues that the ill-fated '17 bike aimed to solve, without, in the words of a senior Yamaha engineer, "ruining the philosophy" of the old machine.

The bike that Yamaha brought to post-season testing at Valencia last year wasn't the final 2017 product, but it set the tone for things to come. Vinales was rapid straight away, topping the timesheets on both days.

Rossi, meanwhile, was ill-at-ease with the new bike. But, as he admitted on Italian radio last week, he assumed - with his new team-mate excelling on the other side of the garage - that the issue was with him, and not the machinery at his disposal.

"The problem was that when Vinales arrived, he went very fast," Rossi recalled. "I tried it [the 2017 prototype] and I didn't like it, but I thought maybe, because it was the end of the season, I was out of shape."

It certainly seemed that way when Vinales followed up his Valencia performance by topping the remaining winter tests at Sepang, Phillip Island and Losail - a state of affairs that left Rossi feeling "worried" ahead of the season-opening Qatar Grand Prix at the last-named venue.

"Maverick likes this because he thinks this is the Yamaha, but I know more of the evolution of the bike, and I think with the 2017 version we lose something" Valentino Rossi

Despite his inexperience, Suzuki convert Vinales went into the Qatar race as title favourite, and duly won on his Yamaha debut. Two weeks later, a second win in Argentina put Vinales 14 points clear of Rossi and seemingly on course for a serious title push.

But it was a false dawn. The relatively cool temperatures at Losail - the result of the race being held under floodlights at night - and a grippy track surface at the recently-constructed Termas de Rio Hondo track concealed the fundamental rear tyre consumption issue of the 2017 Yamaha.

Likewise, Le Mans, the scene of Vinales' third and final victory of the year, had been recently resurfaced, and therefore hid the Yamaha's weakness in hot and low-grip track conditions.

At Jerez and Barcelona, those shortcomings were brutally laid bare, as the year-old bikes of Tech3 duo Johann Zarco and Jonas Folger began to upstage their works cousins.

It was only at these races when Rossi felt he could assert his misgivings about the technical path Yamaha had chosen - after all, when you're being beaten by your team-mate, as Rossi was at the start of the year, it's hard to criticise and be taken seriously.

"Maverick doesn't have any history with Yamaha before coming from Suzuki," said Rossi during post-race testing at Barcelona, when a new type of chassis was tried.

"He likes this because he thinks this is the Yamaha, but I know more of the evolution of the bike, and I think with the 2017 version we lose something."

Rossi got his wish at Assen, where a second, more 2016-like chassis was introduced. The Italian took it to victory in wet conditions, but it robbed Vinales of vital front-end confidence - which, combined with a new spec of front tyre introduced at Mugello, served to gradually edge him out of the title picture.

But August's Red Bull Ring race (pictured), where Zarco beat Rossi and Vinales, confirmed that the rear tyre problem hadn't been fully solved, and a third 'prototype 2018' chassis was introduced in time for Silverstone in a bid to turn the season around.

This seemed to fix the worst of the rear tyre woes, but proved utterly ineffective in wet races at Misano, Motegi and Sepang - and a pair of lacklustre showings in the first two of those venues effectively spelt the end for Vinales' title hopes.

"This bike was made to solve problems which it did not solve" Valentino Rossi

As for Rossi, his broken leg at Misano realistically put paid to any outside hopes he may have been harbouring of that elusive eighth premier class title, although he conceded he still wouldn't have beaten Marquez without that setback.

The final chassis change came in the Valencia finale, where, after a so-so qualifying performance by both works Yamahas, Rossi and Vinales made a last-minute change to use the 2016 frame of Zarco.

With so little time to set up the bike in morning warm-up (Vinales only got two laps in before crashing), it was never going to work in the race. But in Tuesday's opening day of post-season testing, both riders were able to get more mileage on board the old bike, and it was using a 2016 chassis that Vinales set the quickest time.

Problem solved, then?

Not quite. Vinales mysteriously lost half a second using the same machinery on the second day of testing, leaving him baffled, while Zarco - who was two tenths quicker than Vinales on Wednesday - sung the praises of the 2017 bike that Rossi had advised him to steer clear of.

Both of these facts suggested that simply switching back to the 2016 bike wasn't the panacea some observers thought it would be, and equally that the '17 machine may not have been as bad as the results suggest.

"With the '17 I have better traction and better acceleration, and with the '16 I feel better with the front," said Vinales on the Wednesday of the test. "It's what I was feeling during all the year.

"Let's see [whether] we take the '16 and we work to make the acceleration good, or we take the '17 and try to make especially the brakes and the corner speed better.

"We have to decide which way is the easiest to be fast."

That decision was made last week at Sepang, where Zarco joined Rossi and Vinales for one final outing ahead of the two-month winter test ban. All three agreed that the 2017 bike (at least for the factory riders) is to be scrapped for good, and that the '16 version will be the basis for the '18 machine.

And so, Yamaha ends up more or less back where it started at the end of 2016, before three-time champion Lorenzo departed for Ducati and hotshot Vinales arrived.

It begs the question - could all of this misery have been avoided had Lorenzo not been lured to Ducati? Rossi isn't convinced.

"I thought about this, but I think it's a coincidence," he said at Valencia when posed that very question.

"Last year, Lorenzo went off on Sunday and I got on the bike on Tuesday, and I told him that I didn't think the bike was for me. However, Vinales was very fast.

"Perhaps if Lorenzo rode it, he would have agreed with me. But I don't think that it was for this reason [that we struggled].

"In my opinion, the original error was that this bike was made to solve problems which it did not solve."

It's easy to blame Yamaha for messing up with its 2017 bike, but its defeat to Honda the previous year meant it couldn't afford to just rest on its laurels. The problem was that, in working on the M1's weak points, it managed to dilute the things that made it successful in the first place. The things that made it a proper Yamaha, in other words.

Now it's down to the folks in Iwata and Lesmo to combine the best characteristics of the 2016 and '17 bikes in the '18 bike, or risk a repeat of its worst season in MotoGP for a decade.