Ducati's Nicky Hayden will not use the new engine spec produced by his factory at the Silverstone MotoGP round as he couldn't lap Mugello as fast as with the existing motor and he won't use the new swingarm either as it produced chatter on his GP12 but not team-mate Rossi's.

Hayden was full of praise for new electronics which were debuted in testing, though, and says they helped him to get more corner-exit speed and to finish corners properly instead of pushing the front wide - a problem he is currently experiencing.

"I didn't like the new engine. It has its good points but I didn't go as fast with it so I don't think I will use it at Silverstone. I couldn't have used it this weekend even if I had liked it (because of the engine rules). They weren't convinced and it was just something we wanted to try. I don't think we will test it again. I didn't like it for a couple of reasons but ultimately the lap time wasn't as good. There was a bit more power on the bottom but it didn't really help and that hurt a bit on top," aid Hayden at Catalunya this evening.

"Two of the things tested we can use this weekend and should make it a little smoother on the bottom. One of the things we found with the smoother delivery was the turns. At the first touch of the throttle, instead of immediately wanting to push wide, it would help you finish the corner.

"The problem with the swingarm is I like the feeling but I had a lot of chatter. So at the moment, I will probably test it again on Monday. I had better feeling and the bike worked well with it, the front and rear was really balanced but we couldn't get rid of the chatter.

"Even with the carbon swingarm, if I go softer I get worse chatter so for now it's not the right way for me but hopefully we can find something. It was better mid-corner and more grip on the exit. It was working. The bike didn't feel front and rear, more like one piece."