Factory Yamaha MotoGP riders Valentino Rossi and Jorge Lorenzo may be able to make clutch-less downshifts, but they are not yet seamless.

Yamaha joined Honda and Ducati in running a seamless shift gearbox during the second half of last season, slashing the time lost when changing up the gearbox.

Clutch-less downshifts - changing down without using the clutch lever - were then introduced for 2014. Note Rossi's left hand in the pictures below:

Rossi not using clutch lever while braking at Sachsenring 2014

However Honda remains a step ahead due to shorter and smoother 'seamless' downshifts. A crucial part of braking and corner entry.

"Our seamless shift is only upshift and not downshift," confirmed Yamaha MotoGP Group Leader Kouichi Tsuji. "I think the Honda [gearbox] is both up and down, seamless. We are trying to catch up, but when I don't know. We are pushing hard to develop. Maybe this is part [of the gap to Honda] but not everything."

On Thursday at Brno, Rossi stated that Honda seems to have 'found' something and increased the gap to Yamaha this year.

"Honestly speaking our machine is still behind Honda's RCV," Tsuji admitted.

At that point HRC vice president Shuhei Nakamoto quipped: "But our riders complain also!"

World champion Marc Marquez has won every race this season with Repsol Honda team-mate Dani Pedrosa second in the championship.

Rossi had speculated that the 2014 Honda gain is from "something in the electronic and also in the chassis."

Nakamoto rejected the suggestion that there has been some form of technical breakthrough.

"Some people are saying Honda are doing something special, but the reality is not," he declared. "Marc doesn't want to use the Honda traction control system - so our traction control system is the rider's right hand!"

In other words, Marquez favours as little traction control as possible.