20 years ago today, Rossi had his first test on the Yamaha.

Rossi rode his first laps on Sunday the 24th and soon found out why Barros and Yamaha’s other riders had been losing the front and hitting the ground so often.


Pretty much every time he hit the brakes he nearly lost the front. Usually this would suggest poor bike balance and not enough load on the front tyre, because riders need to load the tyre during braking to generate heat and therefore grip. Burgess and his crew checked the data, searching for clues. What they found was quite a shock.


MotoGP engine-braking systems usually keep the throttle butterflies (which regulate fuel/air flow in the injection system) open during braking, even when the rider has the actual throttle closed, because if the butterflies are fully closed there’s too much negative torque, which will lock the rear tyre. For some bizarre reason the M1’s electronics had the front tyre linked into the system, so when Rossi locked the front tyre the engine increased its rpm. A surefire way to make your riders crash!


This is why Barros and other M1 riders had landed on their heads so often during 2003, because the bike started to accelerate when they locked the front tyre! Yamaha simply wrote the front brake out of the M1’s engine-braking program and the problem was solved.

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#22 said:

So really it was Burgess and his crew. Not Rossi.

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