James Ellison is still without any points in the MotoGP World Championship following a disappointing race at Estoril in Portugal.

Ellison was forced to retire with ten laps remaining on the PBM UK Aprilia ART when severe chatter problems returned and forced him out.

The 31-year-old had qualified 19th of 21 riders after struggling with set-up issues.

"Pulling in again was a very, very difficult decision for me as the team worked so hard all weekend to cure the front chatter which is like a very heavy vibration," he said.

"We were making some progress by the time we got to qualifying and had a good plan in place for the race to reduce the problem.

"The start was good and I was fighting at the front of the CRTs like in Jerez for the first few laps but as the tyres wore the chatter got to the point that it became unpredictable and in some of the fast corners it was pushing me a couple of metres off line," added the Kendal man.

"At this point I was only able to ride around and not actually race because it was getting worse. We are working hard on trying to find the source of the problem and I believe that when we do we'll be back at the sharp end of the CRTs."

Team owner Paul Bird had been expecting much better at Estoril after Ellison appeared to be making good progress in the previous round at Jerez, where he was on course to secure his first points of the season before an engine problem thwarted his chances.

"It's disappointing as I thought we'd turned the corner at Jerez but I guess it's all part of the learning curve," he said.

"We'll have a sit down with James and the team this week to try and find a way forward but you've got to bear in mind that this is a very long term project and our little team from up north is competing with the world's best so it will take time."