Yamaha YZR-M1

º En­gine: 999cc in­line-four four-stroke º Power: 265bhp (2019) º Weight: 158kg º Num­ber of wins: 10

BIKE (UK) - - Rossi’s Winners -

When, in 2013, Rossi re­turned to Yamaha af­ter his Ducati dis­as­ter the M1 wasn’t much dif­fer­ent from the 2010 bike, ex­cept Mo­togp had switched to 1000cc en­gines.

Honda were now the ma­jor threat, largely thanks to new sign­ing Marc Mar­quez. Also, their RC213V had a full seam­less gear­box; a seam­less ’box pro­vides quicker and smoother shifts that im­prove ac­cel­er­a­tion and re­duce fuel con­sump­tion. It also re­duces sus­pen­sion up­set which al­lows gear-chang­ing at higher lean an­gles. Yamaha in­tro­duced their seam­less gear­box at Misano, but it only worked on up­shifts, not down­shifts.

In 2014 fuel tank ca­pac­ity was re­duced yet again, this time to 20 litres, and no sur­prise that Yamaha suf­fered the most. ‘My bike is very slow, when I ar­rive on the straight noth­ing hap­pens,’ said Rossi. Yamaha’s other con­cern was cor­ner en­try. Mar­quez was prov­ing im­pos­si­ble to beat, es­pe­cially when at­tack­ing cor­ners. Rossi got a new

frame with a more rigid front end, for bet­ter brak­ing sta­bil­ity, and less rigid beam sec­tions, for more flex in the cor­ners. That said Yamaha’s big­gest step up was their first fully seam­less gear­box, so no need for the clutch on down­shifts. Re­sult: a more sta­ble bike which meant rid­ers could brake harder and later.

As luck would have it, the fol­low­ing year, Honda went the wrong way with en­gine spec and Yamaha cap­i­talised thanks to an M1 that in the last year of Bridge­stone tyres was as close to per­fec­tion as pos­si­ble. Rossi’s main prob­lem was qualifying, be­cause he strug­gled to reach max­i­mum speed in the 15-minute qualifying for­mat. With­out that is­sue he might’ve won the ti­tle.

As usual his chas­sis set-up was dif­fer­ent to that of team-mate Jorge Lorenzo, who won the ti­tle with an amaz­ing seven start-to-fin­ish wins. And then, in 2016, the move to Miche­lin tyres and spec soft­ware changed ev­ery­thing. Thus be­gan Yamaha’s great­est strug­gle: fix­ing chas­sis bal­ance and trac­tion bal­ance. They tried re­vised ge­om­e­try and stiffer fork springs to min­imise the stress on Miche­lin’s front, which worked well in hot weather but not in cool weather when Valentino couldn’t get enough heat into the tyre. When he did have good grip from the front he had wheel­spin and when he had good rear grip he could not make that grip last the race dis­tance. No won­der his crash rate dou­bled.

The search for a chas­sis bal­ance that would get the best out of the Miche­lins con­tin­ued into the 2017 sea­son, but Yamaha’s re­sults got worse, not bet­ter. ‘In 2016 Valentino’s feel­ing with the bike was good, but we de­stroyed the rear tyre with four or five laps to go,’ said Rossi’s crew chief Sil­vano Gal­busera. ‘The chas­sis was mod­i­fied for 2017 to save the tyre, but Valentino lost the feel­ing he had in 2016, so he couldn’t go into cor­ners quickly and keep his line. Then he couldn’t pick up the bike, so he was a bit delayed, so then he had to open the throt­tle more to re­cover that time, which de­stroyed the tyre. It’s a vi­cious cir­cle.’ From Assen 2017 to Phillip Is­land 2018 Yamaha en­dured their long­est los­ing streak since they en­tered the premier class in 1973. In fact they made the bike worse by re­duc­ing crank­shaft in­er­tia – to im­prove ac­cel­er­a­tion – but they went too far, so when Rossi closed the throt­tle the en­gine shut down too quickly, mak­ing the rear end snappy, and when he opened the throt­tle the en­gine picked up revs too quickly, caus­ing wheel­spin. How­ever, the plus side of this equa­tion was at least it helped en­gi­neers un­der­stand what they needed: a chas­sis that al­lowed the bike to spend less time at full lean, thereby ask­ing less from the edge of the tyres, and friend­lier power de­liv­ery, to help the rear tyre in ac­cel­er­a­tion.

Yamaha’s fun­da­men­tal prob­lems re­mained when 2019 dawned: poor ac­cel­er­a­tion and tyre life. Rossi had his worst sea­son yet with Yamaha. ‘We suf­fer ev­ery­where,’ he said at Mugello, where the M1 was the slow­est bike on the grid.

Yet, late in the sea­son, things be­gan to turn around. ‘Yamaha are fi­nally start­ing in the right di­rec­tion,’ he said. ‘They start to do clever things, so the sit­u­a­tion is very much changed com­pared with the last two years.’

Rossi ended the year third best M1 rider, be­hind team-mate Mav­er­ick Vi­nales and rookie Fabio Quar­tararo.

‘Yamaha are fi­nally start­ing in the right di­rec­tion. They start to do clever things’

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