Jack Miller is fed up with the difficulties he's encountered with the Yamaha V4. After his crash on lap five of the Indonesian Grand Prix, the Pramac rider points to a particularly baffling behavior: a bike that looks promising in practice, but becomes almost impossible to ride as soon as it's switched to race configuration. Engine mapping, excessive fuel consumption, unstable braking… The Australian suspects a deeper problem than simple adjustments. And as Phillip Island approaches, the situation is becoming particularly frustrating.
There are some bikes that are difficult to set up. And then there are those that seem to change their personality between practice and the race. Jack Miller believes he's dealing with the second category. At Mandalika , the Australian experienced another nightmarish Sunday, ending with a crash on the fifth lap.
But the result is almost a minor detail compared to the symptoms he describes. According to him, the Yamaha V4 can provide satisfying sensations in the morning before becoming practically uncontrollable a few hours later.
Miller: As soon as we switch to race configuration, the motorcycle becomes unmanageable. »
Speaking to Speedweek , Miller didn't hide his bewilderment. " I had a very good feeling in the morning, or at least a pretty good feeling. But as soon as we switch to race configuration , the bike becomes almost unmanageable ."
The Pramac rider explained that he had regained an encouraging balance during the sessions leading up to the start. Then everything deteriorated when the machine was prepared for the Grand Prix distance.
" Whether it's the fuel injection mapping or something else, there's something going on behind the scenes that makes this motorcycle very difficult to ride ." Miller is therefore putting forward a technical hypothesis, without claiming to have definitively identified the cause. The engine mapping is suspected, but not officially acknowledged as responsible.
Braking, engine, fuel consumption: three worrying symptoms
The difficulties described by the Australian go far beyond a lack of grip. " I'm having trouble slowing the bike down, and the engine isn't running properly ." Miller then added, " Our fuel consumption is still too high . We need to fix this. "
This last point deserves attention. In MotoGP, fuel management influences electronic strategies, power delivery, and the possibilities for adjustment over the distance of a race.
If Yamaha has to contend with excessive fuel consumption, the engineers may be forced to make compromises that affect the prototype's handling. This could help explain the discrepancy between the feel during testing and on Sunday.
But Miller himself doesn't establish a definitive causal link. One thing, however, is beyond doubt in his testimony: the problem also manifests itself under braking. " I can't brake the bike, I can't turn it. As soon as I start to push, the front wheel locks up ." Under these conditions, it's difficult to establish a competitive race pace.
Yamaha V4: a development that still raises questions
The adoption of the V4 engine was expected to open up new technical perspectives for Yamaha . However, the engine architecture does not automatically resolve the integration difficulties between electronics, engine braking, chassis, and fuel management.
Miller 's testimony illustrates this complexity. A motorcycle capable of displaying encouraging balance for a few laps, but unable to maintain this behavior in a race, presents a particularly penalizing consistency problem.
And Mandalika offered no solace to Pramac. Toprak Razgatlioglu also withdrew, hampered by a shoulder injury sustained on Saturday. The team thus leaves Indonesia without a result, but more importantly, with persistent technical questions.
Phillip Island, a meeting full of symbolism for Miller
The next step will take Miller to his home turf, Phillip Island . A fast, demanding circuit where confidence in the front end and bike stability are essential. " We're going to Australia and we'll see what we can achieve there ," he concludes.
The event will have a special significance: MotoGP is set to leave Phillip Island in 2027, while Miller is slated to move up to World Superbike next season. He could therefore quickly return to the Australian circuit in a different category.
But before even thinking about this new adventure, there's an immediate problem to solve. At Yamaha , the question is no longer simply how to make the V4 fast. It's about understanding why a bike that shows promise in the morning becomes, according to Miller , almost impossible to ride on Sunday. And as long as this contradiction persists, the progress made in testing risks disappearing precisely when it matters most.
