A new lever was spotted on the 2014 Factory Yamaha MotoGP machines of Valentino Rossi and Jorge Lorenzo during pre-season testing (top picture).

Yamaha were tight-lipped regarding the exact purpose of the small lever, located between the clutch and handlebar on the left side of the bike. However Honda has been seen with a similar extra lever (see handlebar images below) since the first half of last season.

Speaking to Crash.net, Yamaha team director Massimo Meregalli would confirm only that the new lever is related to the latest 2014 transmission and is not a clutch.

Although the obvious advantage of a seamless gearbox is time saved during acceleration, the shorter, smoother shifts also make the motorcycle more stable - especially beneficial when accelerating out of corners.

However it is in deceleration that Yamaha is now focussing its seamless development.

Heavy braking and corner entry is considered Honda's main advantage, with RCV riders rumoured not to need the clutch lever when downshifting. Certainly, when trackside, the individual downshifts on the Honda are barely audible during hard braking.

"Honda has seamless down [the gearbox] as well," declared Rossi. "Us no. It is an issue that we push for Yamaha to improve."

"We are trying to shift down in the braking like Honda, but for the moment it is worse than last year," added Lorenzo, casting doubt on whether the latest updates associated with the new lever will actually be present for the start of the racing season.

The fact the lever is so small implies that it is not designed to be used at racing speeds and the most plausible theory seems to be that the lever is used to engage neutral/start the bike.

This is connected to the belief that in order to optimise the seamless effect - which sees two gears 'engaged' at the same time - the Honda and latest Yamaha gearboxes have moved neutral from between first and second on the gearshift pattern (1-N-2-3-4-5-6) to the top of the order (N-1-2-3-4-5-6).

The problem with the revised gearshift pattern is that it is easy to accidentally select neutral by making one too many downshifts under hard braking for a slow corner. With the normal racing order, the bike would remain in first gear.

Therefore, the theory goes, neutral now needs to be 'locked away' when on track and accessible only by pulling the special lever. This lever may in turn be needed when push starting the bike and the location of the lever shows that the rider requires occasional access to it.

Last year's initial Yamaha seamless gearbox is understood to have only been seamless from second gear onwards (not first to second) which would confirm neutral was in the normal place and no need for an extra lever.

So Yamaha's 2014 modifications probably mean its gearbox is now seamless for all upshifts, while work continues on Honda-style seamless downshifts.

Either way Meregalli wasn't telling, "I can't say because it's a technical matter, you have the pictures so why not ask Crash.net readers what they think it is..."

More images of the extra Yamaha and Honda levers, plus the normal 2014 handlebar layout for Forward Yamaha's (non seamless gearbox) machine of Aleix Espargaro, can be seen below.