Reigning MotoGP world champion Casey Stoner finished just tenth fastest during Thursday afternoon's practice session for the Dutch TT at Assen.

The Australian recorded just four fast laps in-between frequent visits to the Repsol Honda pits and was the only rider to lap slower than in the morning session, when he had been third fastest.

Afterwards Stoner explained that he was having major handling problems.

"In FP2 we couldn't get any feeling from the rear and to be honest I felt a little nervous on the bike because from the first two exits, the bike just wanted to throw me off," said Stoner.

"Every time I touched the throttle the rear wanted to come around on me and I lost the front quite a few times, too many for my liking.

"Everything we're doing, trying to reduce the chatter is just making the bike difficult to ride," he continued.

"We're going to have to rethink things again and come out fresh tomorrow. I'm not too worried about finding the pace, it was just a little bit disappointing this afternoon".

Stoner, who remained on the harder rear tyre this afternoon, also revealed that he had used a new chassis to try and improve the ongoing chatter issues.

"We tested another chassis but haven't found many positives with it yet, in the morning it felt like we had slightly less chatter in the front, then this afternoon no real benefit, perhaps a little worse," he said.

Despite his problematic afternoon, Stoner was only 0.438s from fastest man Ben Spies (Yamaha). Stoner's team-mate Dani Pedrosa was sixth quickest, with title leader Jorge Lorenzo in fifth.