Roberts Jr won't ride at Donington

The American will stand down from duties as he feels he has got the most out of this current chassis for the time being.

His younger brother Kurtis will ride the sole entry for the team, as Honda have scrapped plans to run British Superbike rider Jonathan Rea in the team at Donington.

Former 500cc world champion Roberts Jr will return to racing at Laguna Seca in five weeks' time, when the team will have a new chassis ready.

Team KR manager Chuck Aksland said: "From Kenny Jr's side, it has been very frustrating, as the fundamentals of the machine seemed fine since we started testing.

"He is the same rider that put our bike on the podium twice last year and we thought heading into this season we could do better. For whatever reason we have not."

Despite their poor start to the season the team are still confident that they can return to the levels of performance that enabled Roberts Jr to finish sixth in the MotoGP standings last year.

"There have been a lot of changes," said Aksland. "It took some time for is to get the 990 right and we are confident we can bring the 800 around as well. We just need some more time.

"Kenny JR has ridden the current spec enough and we decided the best time for him to come back would be when there are new parts available to get the KR212V closer to the front.

"Kurtis has done a good job for us during the last two races and he is improving each time he gets on the bike. Unlike the previous races, he now will have two machines available which will help him gain additional track time."

Rea was scheduled to ride a second Roberts bike, but Honda have decided to change his plans after recent victories in British Superbikes and the Suzuka 300km.

Aksland added: "It's unfortunate Jonathan won't be able to compete with us at Donington. The whole team was looking forward to working with him.

"He's had a good run lately and Honda have decided that it is best for him to stick with his current priorities which obviously lie in the British Superbike Championship and Suzuka eight-hour event."