Three crucial areas pinpointed for Yamaha’s pivot towards a V4 engine

The reasons for Yamaha’s pivot towards a V4 engine have been analysed by Simon Crafar.

The Japanese manufacturer confirmed ahead of this weekend’s Emilia-Romagna Grand Prix that they are developing a V4 powerplant in a massive shift in focus.

Yamaha have used Inline four-cylinder engines since the start of the MotoGP era.

“When I first heard it, during the test, I couldn’t believe it! But where it came from was very believable,” said Crafar from inside the Misano paddock.

“I thought ‘Yamaha are really doing this’.

“It’s super impressive, I can’t wait to see the bike. I’m glad they’re not trying to hide it or keep it quiet. They are being open about it. This is magic!”

Yamaha are currently the only MotoGP manufacturer who are not racing with a V4 engine.

But Crafar said: “All the digging I’ve been doing in this job, speaking to engineers, there is nothing wrong with an inline-four, pure-performance wise. There is not.

“Engineers give me reasons why. The exhaust length cannot be the same on a V4 because of the position of the bike. They want to keep the exhaust length the same for all cylinders, but they can’t, on a V4.

“The inlet length, because they are in different positions…

“The heat for the back cylinders on a V4… there are downsides.”

However, Yamaha are clearly now focused on the potential upsides of a V4 engine.

Crafar said: “The big one, for me, is how narrow the V4 is. It’s only two-and-a-half cylinders wide, a lot narrower, so you push less air.

“Aprilia told us that they went from 82 degrees to 90 degrees, the oil injection and air box can be lower. So the rider position and the screen are lower.

“Not only narrower, but lower. They push less air. The top speed and acceleration get better.”

Crafar suggested the reasons why Yamaha might have opted for this sizable change of direction.

“Chassis design is affected by the narrowness. And manoeuvrability,” he said.

“We’ve heard complaints from Fabio Quartararo about how heavy the machine is.

“I could see Alex Rins and Fabio absolutely destroyed at the end of Mugello where there are so many second-guess chicanes.

“I think that is a part of it, as well.

“The smaller frontal area and manoeuvrability, and maybe chassis design, are part of their decision.”