Yamaha MotoGP men Valentino Rossi and Cal Crutchlow have expressed huge concerns over how close they come to not finishing races due to the fuel regulations and says the problem does not end there.

Both Crutchlow and Rossi are both heavier than their front-running counterparts with the British rider saying they have to be so careful not to use too much fuel on the sighting and warm-up laps, they don't scrub their tyres properly.

"Valentino and I are at the limit with fuel. One race he runs out, the next I run out, depends if you have a slipstream but one of us runs out. If we were on 20 litres now we would have finished two races this year, which shows what is about to come," said Crutchlow, speaking at Aragon.

"Where we are losing, for sure, is on the first lap. Valentino and I believe it is a lot to do with the sighting lap to the grid as we have to ride at 30kph which means we can't scrub the tyre.

"Then on the warm-up lap, we are trying to get the shine off the tyre and we're already a lap behind as Jorge is lighter and has a different riding style, he is able to push from the start and we are not. Mind you, it is also him. But we are cutting too much power and we can't compete because we don't have enough fuel."

Rossi agrees and says that taller and heavier riders suffer far more compared to the jockey-like statures of Marc Marquez and Dani Pedrosa. Even Lorenzo is some five kilos lighter than his teammate.

"We are in big trouble with 21 litres, imagine with 20. For me the big problem is the heavy and long rider have double disadvantage compared to the small and light rider because you have to use more fuel so you are more in the shit," said The Doctor.