Factory Yamaha's Valentino Rossi believes that although the much-vaunted seamless gearbox is very important in he and team-mate Jorge Lorenzo's chase for the title, other things need to be improved to make a difference.

At Indianapolis, the YZR-M1 was made to look silly in terms of acceleration and top-speed compared to the Repsol Hondas. So much so, in fact, that Dani Pedrosa's effortless pass on Lorenzo was 'embarrassing', according to Cal Crutchlow.

Rossi says there are more areas to work on with the bike to try and keep pace with the two works RC213V machines and the seamless gearbox, whenever it turns up, is more of an icing on the cake.

"I think the seamless is very important for try to be faster. I also think it is not enough. We have to continue to work on the bike because we have some other problems compared to the Hondas at this moment which give is some more difficulties to keep the pace," said The Doctor, speaking at Brno.

The pair tested at Brno two weeks ago during the summer break but spent a lot of that time working on the new gearbox so it will not have given the Yamaha pair any huge advantage, although it will suit the M1 much better than Indianapolis.

"Here we have to do better. We have to be more in front in the practice and set a good pace for all the race. Our bike likes the wide track and fast corner. For me testing was a good help but it doesn't make a difference. We spend a lot of time here trying to improve the gearbox.

"Brno is a track that I like a lot, where I made good races and won a lot. We also tested on this track a few weeks ago. Marquez and Honda in general are going very strong, but we are defending well."