Video Aprilia RSV4 at Mugello: one bike, two motors?

Expectations are running high for the Noale superbike, the Aprilia RSV4 1000.
Curiosity has been sparked as it appears this bike has more surprises in store.
In this video from a fan at the Mugello circuit, we can hear a different noise than that of the V4, 65° engine.

Around 1′47″, the sound changes and it seems that this prototype could have a second motor than originally thought.

It’s unclear whether the different tone arrives from a different electronic configuration or from a more open exhaust.
Whatever, it’s sent shivers up the spine.

After the jump is the official presentation video of the superbike – the sound of which is similar to that produced in the first tests at Mugello.