December track debut for Yamaha's V4 MotoGP bike ‘would be wonderful’
MotoGP
Yamaha’s fight to get back to the front of MotoGP is already well underway, with its all-new V4 bike soon to be track tested. Plus, why downforce aerodynamics was the biggest factor in Yamaha’s decision to build a V4
Don’t get too excited! This is Yamaha’s first four-stroke V4 MotoGP engine, built in 1980, but never raced. The engine had seven valves per cylinder (four intake, three exhaust) and made 120 horsepower, only five less than the 0W48 500cc two-stroke that ‘King’ Kenny Roberts rode to that year’s MotoGP championship
Yamaha’s all-new V4 MotoGP bike could have its rollout test next month. The 1000cc machine is expected to turn its first high-speed laps at Sepang, Malaysia, most likely by former MotoGP race winners Andrea Dovizioso and Cal Crutchlow, if the Briton is fit.
Yamaha confirmed the machine’s existence in September, following months, even years, of speculation. The engine has been on the dyno since the summer, which suggests the project was probably commenced last winter.
The all-new machine marks an expensive reorientation for Yamaha, which has raced its inline-four YZR-M1 since MotoGP switched to large-capacity four-strokes in 2002, winning eight riders’ titles and five constructors’ crowns. However, in recent years it’s become more and more difficult for inline-fours to compete with V4 machines, currently used by MotoGP’s other manufacturers: Aprilia, Ducati, Honda and KTM.
Yamaha’s MotoGP department found itself in the doldrums in the early 1980s, not unlike the last few seasons. The company may have won 1978, 1979 and 1980 500cc/MotoGP world championships…
By
Mat Oxley
Not only that, it’s not easy being the outlier in motor sport. Technology tends to move with the majority, so if you’re taking a different road, it’s easy to get lost.
Yamaha’s M1 hasn’t won a grand prix since July 2022 – 40 races ago – and hasn’t scored a single podium this year. Last Sunday’s Malaysian GP at Sepang was easily its best performance of 2024 – its first double top ten, with Fabio Quartararo finishing sixth and Álex Rins eighth.
Rolling out the V4 at Sepang makes all kinds of sense, because the track is so well known by riders, engineers and data analysists.
However, Yamaha technical director Max Bartolini has yet to confirm the December date.
“December looks to be optimistic – it would be wonderful but at the moment there’s nothing we can say for sure,” he said at Sepang last weekend.
Dovizioso had his last competitive MotoGP ride with the RNF Yamaha team in 2022 – he’s spent a lot of time working with Yamaha engineers in recent months
Michelin
Yamaha took the decision to build a V4 for various reasons.
Many engine designers believe that inline-four engines have their limitations – at over 18,000rpm their wider crankshafts and camshafts can suffer from vibration and torsional twist, which can upset the drivetrain and cause valve float. A V4’s shorter cranks and cams are more robust, so these engines can be tuned more aggressively.
Inline-four MotoGP bikes have topped MotoGP’s top-speed charts only three times in the last five seasons. The last time Yamaha’s M1 had the best top speed during a GP was at Motegi in 2018, 113 GPs ago!
This weekend’s Japanese Grand Prix is obviously a big deal for MotoGP’s remaining Japanese manufacturers, but this year’s event is particularly significant, because if neither Honda nor Yamaha win at…
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Mat Oxley
Top speed may not be super-important to lap times, but it gives riders the chance to set up overtakes, a vital advantage in MotoGP.
Cornering lines are another well-known V4-versus-inline-four issue.
The inertia of an inline-four’s wider crankshaft stabilises the machine, which is why these bikes tend to be so user-friendly and so fast around corners.
V4s are twitchier, so while inline-fours can take fast, sweeping, U-shaped arcs around corners, V4 bikes essentially make the corner as short as possible by using V-shaped lines. And how can the rider of an inline-four exploit his faster U-shaped line when he’s fighting with a bunch of V4s, taking different lines and getting in his way? He can’t, so he’s lost his main advantage. Simply put, a V4 is a better battling bike.
Although these elements played their part in Yamaha’s decision to build a V4, the biggest factor was downforce aerodynamics, currently MotoGP’s biggest area of development.
Inline-four engines are wider than V4s (four cylinders across the frame instead of two) which means their fairing bodies are also wider. MotoGP regulations limit total machine width to 600mm, so aerodynamicists working with a V4 have more scope to play with aero shapes, wings and so on, which allows them to create more downforce to increase grip and go faster around corners.
MotoGP’s machine width rules will give V4s an even bigger advantage from 2027, when the championship’s new technical rules reduce total width to 550mm. That will make it even more difficult to create effective downforce aero around an inline-four.
“Yes, one of the possible advantages of a V4 is aero,” explained Bartolini. “When you have rules that fix the machine width and you have a wider engine then you will have issues.”
Quartararo had his best result of 2024 at Sepang last Sunday – sixth place and chasing home KTM’s Pedro Acosta
Yamaha
Of course, none of this means that a V4 will cure all Yamaha’s ills. Therefore factory engineers are keeping an open mind and will continue developing both projects in parallel.
“It’s not like choosing a V4 will lead us to be easily competitive,” added Bartolini, who joined Yamaha at the end of last season after two decades at Ducati. “Yamaha is clear that we need to make a faster motorcycle, so if for some reason the V4 is slower than the four-inline, we will stick to the four-inline.”
Yamaha’s goal is the usual MotoGP goal: to build a motorcycle with a fast and friendly engine, a well-packaged chassis and effective downforce aerodynamics, all focused towards achieving the only thing that really matters – generating maximum grip from the tyres. This is one of many areas where the current M1 is failing.
Its MotoGP department will be busier than any other MotoGP department over the next few years.
The other manufacturers will split their time between making their 1000cc MotoGP bikes as fast as possible for the next two seasons, while also developing bikes for MotoGP’s new technical era from 2027: 850cc engines, trimmed downforce aero and no devices.
Yamaha will be working on four motorcycles: an inline-four 1000, a V4 1000, an inline-four 850 and a V4 850. At least until it makes a final decision on which direction to take for the future.
Next year it will have four riders on the grid for the first time since 2022, with factory riders Quartararo and Rins joined by Jack Miller and Miguel Oliveira, riding factory-spec bikes for Pramac.
My full interview with the fascinating Max Bartolini will appear here in the coming weeks.
