Factory Yamaha's Valentino Rossi has re-iterated his plea to Yamaha bosses that the YZR-M1 ridden by himself and reigning MotoGP champion Jorge Lorenzo must improve drastically if he has any chance of beating the works Hondas.

The nine-time world champion was fourth in today's Brno clash, five seconds behind Lorenzo but even the Spaniard, who led for two-thirds of the race, had to give best to the RCV213V pair at the end as he couldn't live with the pace.

"They are very, very strong. In the last two races we try to work with a different bike with different setting for try to improve my problem in braking but we suffer too much with this type of setting so we have to continue to work," said The Doctor, speaking at Brno.

"Because I suffer too much in the qualifying, starting from behind is more difficult especially when you have to stay with the top three at the beginning of the race make a big difference.

"The technical side is not so good for the Yamahas and we have to work. The two factory Hondas are very strong. I think Jorge tried to maximum to stay in front but have to give up. He arrive in front of me about seven seconds - I want to stay closer and fight with the other guys and I have to be more strong.

"We have to follow another way for the setting. We try to modify the setting of the bike for improve my problem in braking and, sincerely, braking is a bit better but anyway I am not fast enough.

"Yamaha work very strong and do not like arrive behind Honda. We have a lot of things to improve. They work already on a lot of things, the seamless is the first but also other part of the bike as we suffer a bit when we open the throttle compared to the Hondas.

The bike in general is very good but at this moment, the other guys have something more. So we have to work now from the setting and then, for the future, work in general to improve the bike."