The real reasons Yamaha built a V4 MotoGP bike

It’s not very often that a totally new motorcycle appears in MotoGP.

Yamaha‘s YZR-M1 V4 is the first brand-new bike since KTM‘s RC16 made its MotoGP debut nine years ago, so it’s a big deal.

The Iwata manufacturer’s decision to park its M1 inline-four — winner of 13 riders’ and constructors’ titles between 2004 and 2021 — completes the V4’s takeover of MotoGP.

And not only the V4’s, but specifically the 90-degree V4’s. All five manufacturers now race MotoGP bikes powered by 90-degree V4 engines (in fact, the RC16’s vee is 86 degrees wide to save a few millimetres in engine length), because this is how racing works — engineers tend to copy the winning formula.

The final decades of 500cc MotoGP were the same, with a fully homogenised grid of two-stroke V4s, which won the last 36 500cc rider and constructor titles over 18 years. And, funnily enough, while Yamaha is the last brand to race a four-stroke MotoGP bike, it was the first to win with a two-stroke V4, the 0W61 of 1982, a configuration soon copied by Honda and Suzuki.

Why does everyone love a V4 now? A V4 engine’s crankshaft and camshafts are shorter than an inline-four’s, so they’re less likely to twist and vibrate at high rpm, so a V4 can make better power. A V4 engine is also narrower, which helps chassis and aerodynamics engineers.

Obviously, the new M1 isn’t just an old M1 with a new engine, it’s an entirely new motorcycle, with a brand-new chassis, which gives a different machine balance to make the tyres work better over race distance. And so on and so forth…

The man to tell us the full range of reasons to go V4 is Yamaha’s technical director Max Bartolini, who joined the company at the end of 2023, after a decade as Gigi Dall’Igna’s right-hand man at Ducati.

Oxley: This must be a very complicated year for you, because it’s not very often that a manufacturer races two completely different motorcycles – an inline-four and a V4 – during the same season.

Bartolini: At the start of the season we balanced our resources in one direction and then during the season we moved more resources to the new project, while still doing a bit of development with the current bike, mostly to develop concepts we want to apply to the new bike.

Balancing our resources has been the difficult part, because this company’s resources aren’t unlimited. We don’t have as many staff as some people think we have. Yamaha is a big company, but the race department isn’t so big. It’s not like Honda.

How many times do you visit Yamaha’s race department in Iwata?

So far, five times this year. In August I spent the holidays working at YMC [Yamaha Motor Company] in Iwata. My wife came with me – she stayed in Tokyo for two-and-a-half weeks while I worked at Iwata and we saw each other at weekends. I will visit again after Valencia, so six or seven times this year.

When did you decide to race the V4 at Misano?

We tried to bring the bike to a race as soon as possible, because we want to speed up the project and as, you can imagine, developing a completely new bike is always a disaster [Bartolini means very complicated and challenging!], so we thought it was better to risk racing the bike as soon as possible, because even if the bike had problems, it’s always easier to understand where you are [in terms of relative performance] during race weekends, because you have the same grip as the other guys, the same tyres, the same conditions and so on, while during tests they’re never the same.

We decided on Misano three months before [in June]. Augusto will also race the bike at Sepang [at the end of this month], because again the idea is to have the bike race in very difficult conditions, and at Valencia, so in the end we will make three ‘test’ wild card races this year, because it’s the best way to speed up the process.

For a test rider, Augusto Fernandez showed some good speed when he raced the bike for the first time at Misano last month – 1.2 seconds off pole and 1.4 seconds off the fastest race lap.

In general, I can’t say the weekend was perfect but, honestly, it went better than we expected. We were expecting much, much more problems and to be slower than we were. Like always with a new project we needed to manage some, let’s say, unexpected behaviour from the bike, but that’s quite normal. It’s also true that the bike doesn’t yet have the correct balance, so we didn’t even work so much on the settings at Misano.

And presumably you’re not using the engine’s maximum rpm yet?

Right now the engine isn’t ready. Sometimes we can use some revs, but the engine isn’t yet developed to a state of maximum power.

After a positive weekend with Fernandez at Misano, were you surprised that Fabio Quartararo wasn’t so impressed by the bike during the Monday tests?

Not really. I think the good points were what we expected and the bad points were what we expected. Fabio wasn’t so slow – around one second off the pace with a completely new bike and we clearly saw in the data where we need to improve.

Misano is quite demanding for the front, with very little straight-line braking but lots of braking from very high speed, with a lot of combined force on the front tyre [lean angle/brake load]. But we haven’t yet arrived at the correct balance with the new bike, so it’s not OK for front feeling.

We didn’t work to set up the bike in the tests either, because it’s still early stages, so we still need to decide where to put the balance and where to put the front wheel. And when you are at this point it’s very difficult for a rider to get the confidence to go faster. I understand this is difficult for Fabio, because he wants to fight for the win.

Fabio is an amazing natural talent – how analytical is he?

Fabio is very powerful and sometimes he struggles to put that power in the right direction. In talent, I think he’s very, very talented — more than you can imagine from the outside, so I was surprised when I arrived at Yamaha.

About analytical ability — he has this fire inside him, which sometimes covers other things, because he wants to be fast. Later, when he calms down, he’s better, but he needs to calm down first.

What are your priorities now?

We need to improve the engine and at least to get to the level of handling of the other bikes, by finding the right bike balance to gain front feel. I’m not sure the new bike’s front will ever be like the current bike’s, because in the end, when you gain something, you lose something.

These are the main points we are working. The good point is that Augusto and Dovi [Andrea Dovizioso, former Ducati MotoGP winner who now works with Yamaha] say the same things, which is why what Fabio said during the Misano tests wasn’t unexpected, because he uses the front much more strongly than they do, so when Augusto had [earlier] complained about the front, I said, ‘F***!’ because I knew when Fabio tried the bike he would complain more about this and he did.

There are many reasons why a V4 works better in MotoGP now, like the inline-four is wider, so the engine needs to be higher in the chassis, so you can’t get the swingarm pivot in the right place to get the right amount of chain force…

Chain force is one of the points but not the most important point.

What are the other big points?

Okay, aero is one of the first.

Because a V4 is narrower and makes more power, so it can carry more downforce aero?

Power isn’t the main reason, because I still think an inline-four can have the power. The first problem is rideability, because in the past the M1 had a very smooth engine, but now you can’t make a torque curve with the same shape as a V4’s torque curve, plus you need a balance shaft, so it becomes a very complex and heavy engine.

Why can’t you make a good torque curve – because you need light engine inertia, so the engine revs to make the power?

Yeah, very light.

Then you get wheelspin because you’ve so little engine inertia?

Then you have to add more inertia and you end up with a very, very heavy engine.

For me, these are the biggest points, plus the balance of the bike – the height of the centre of gravity and the position of the centre of gravity compared to rider position. We can put more load on the rear tyre with the current bike, but the front wheel will end up under the rider’s feet. So everything goes in that [V4] direction.

I’m not sure you couldn’t make an inline-four that works now, but you’d have to completely change the concept of the inline-four and how it works. Then this would be something away from the other bikes, so you would need to do something nobody else is doing, so in the end, it’s best to stick to what everybody knows.

Also, when we move from Michelin to Pirelli in 2027, I honestly don’t expect the Pirellis to work in the opposite direction of the Michelins.

If that did happen, at least you’d have the inline-four to bring back…

I’d be surprised if that happens with Pirelli, but if we went back to Bridgestone, the inline-four would be pretty good! [Because Bridgestone’s amazing front slick favours front-focused motorcycles.]

Obviously, you brought a lot of V4 know-how when you joined Yamaha from Ducati…

I worked on the same bike [the Desmosedici] for many, many years, so I’ve tried to share my experience, but like in every company, you need to bring people to understand what you mean and go in the same direction and this requires a little time. Because, thinking in the opposite way, when people came to Ducati from the outside, also Ducati struggled to understand. [I wonder if he’s talking about Gigi Dall’Igna.]

I try to explain things in a better way – I make sketches and so on. Because even if you brought a whole bike with you, it’s very difficult to make that same bike somewhere else, unless the people understand the concept behind the bike. Also, I don’t think it’s proper to arrive in a company and tell them, ‘This is how we make a bike.’

Yamaha have many positive points that we didn’t have at Ducati, so now at Iwata we share experiences and try to make a better bike overall. For sure I have in my mind what we did to improve the bike at Ducati and we will try to do some of that here.

I recently watched Hitting The Apex [excellent 2013 MotoGP doc] again and the bikes were so short!

Compared to then, because of the increase in power, MotoGP bikes are now around 60 to 70mm longer.

Why doesn’t Quartararo turn up at races with one guy filling the inline-four’s fuel tank and one guy fitting tyres, while everyone else stays at Iwata, working on the V4?

In some ways are you right, but another thing we are developing is the way to work in the garage, so the guys at the track are learning new ways to work and whatever we learn today will be useful with the new bike. The people at the track are racing guys, not designers. Then there’s me and project leader Kazuhiro Masuda, who are trying to make the bridge between the Japanese side and the Italian side.

I know Yamaha’s Milan MotoGP engineering base is growing – what work do you do there?

We are doing part of the aero, engine building and some engine development.

Is Luca Marmorini [former Ferrari Formula 1 engine designer, who worked briefly with Aprilia before joining Yamaha in 2022] still with you?

Yes, he is a consultant, but we consider him more of a partner, a long-term partner. It’s easy to find many engine experts but not easy to find MotoGP engine experts, so it’s good to have him, even if the engine department in Japan is also quite strong.

Do you now use a virtual garage (basically a replica garage housed in the manufacturer’s race department, linked to the track via live audio, video and data) in Iwata and Milan?

We don’t have enough resources yet, but the data goes worldwide.