Every factory team is dealing with the 20-liter fuel limit imposed on bikes racing in MotoGP. We haven't seen anyone run out this season – save maybe Ducati's Cal Crutchlow at Qatar – which begs the question: how? If four-time 500cc racer Randy Mamola is to be believed, it's because the crew at Repsol Honda is using cylinder deactivation.

Mamola spoke at Cycle World's Indianapolis Industry Panel a couple months back emanating from the bikes of Marc Marques and Dani Pedrosa on one of the long, sweeping bends at Catalunya.

As soon as one of the machines would reach a steady throttle state, its engine note would switch from the higher pitch of a V-4 to the deeper tone of a triple. When the rider moved the throttle to accelerate, the engine would revert to four cylinders.

Digging up a couple videos and you can almost hear what he's on about.

Here's Marquez:

And here's Pedrosa:

If Honda's using some form of cylinder deactivation when riders are giving it a minimal amount of throttle it could pay dividends both in longevity and power delivery. And as far as I can tell, it's the first time cylinder deactivation has been used in MotoGP.

Here's a full onboard lap of Catalunya where there's no audible switch. But then again, this isn't during a race, where fuel savings are key: