By Stephen English

Despite a near perfect start to the 2012 MotoGP season, Jorge Lorenzo insists he needs further 'go faster' parts for his factory Yamaha.

The Spaniard has claimed four wins from the opening six races, including Sunday's Silverstone round, and finished second in the other races.

With such a dominant start to the campaign Lorenzo has opened up a commanding early advantage of 25 points to his nearest challenger Casey Stoner (Honda).

Speaking after the British Grand Prix, Lorenzo was asked to compare his current bike with the title-winning 2010 800cc M1.

The race victor said, "This is the fastest one because it's the 1000cc! It's good. It's good. In 2010 I also had a good bike compared to the others and it won us many races.

Even after such a great start to the campaign, Lorenzo stressed that his M1 still has some flaws to correct if he is to maintain his championship momentum.

"We need to improve some things," said Lorenzo. "Especially the engine as it is not fast enough. The corner speed is quite good and that's why we are able to be with them [the Hondas]."

Lorenzo - who recently signed a new two-year deal with Yamaha - tried a new spec engine at the recent Catalunya and Aragon tests, but did not feel that it offered a noticeable improvement.