The speculation over who is to ride the Kenny Roberts' MotoGP bikes this season -- which are designed and built in Banbury -- is finally over.

No.1 rider Jeremy McWilliams raced for the Proton KR squad for the last two seasons, but his future was thrown into doubt at the final 2003 GP in Valencia, when the squad split with tyre supplier Bridgestone

The Ulster ace decided to swap teams and join "Shakey" Shane Byrne in an all-British factory Aprilia MotoGP squad this year.

That left the Banbury team in a quandary, both for riders and the all-important race tyres.

Although the question of tyre manufacturer is still in the balance -- it will either be Dunlop or Michelin -- the riders issue has finally be decided.

Kurtis Roberts -- second son of the legendary triple champion Kenny Roberts Snr -- has stepped into the breach, joining established Proton Team KR rider Nobuatsu Aoki for a two-man assault on the 16-race calendar.

For Japanese racing star Nobuatsu, aged 32, it will be his third year with the independent racing team.

Aoki, who was the first rider to score championship points last year on the all-new four-stroke prototype, agreed terms to remain with Proton Team KR early in January.

He said: "I am glad to stay with this exciting project. I was in it from the start, and it means a lot to me to be able to develop a completely original racing motorcycle."

Kurtis reached final contractural agreement last week. The announcement followed the 25-year-old ex-AMA Superbike race winner's test-ride on the V5 machine at Valencia last month.

Donning the number 80, he bolstered hopes of future success on his first outing on a 990cc MotoGP machine by setting a faster lap time than the howling four-stroke had run at the GP only a few weeks earlier.

It is a return to GP racing for Kurtis, who campaigned a privateer 250cc bike in 1997, aged 18.

The following year Kurtis went back to the US, where he won three AMA titles (SuperSport 600 and twice Formula Xtreme) by the age of 21. Moving to the AMA Superbike class, he won two races last year on the way to a second successive top-three championship finish.

He said: "I'm very excited about MotoGP. It's like going home for me -- the tracks, the people and the atmosphere. It's where I grew up, and it's where every racer wants to be."

For team boss Kenny Roberts Snr, this is the second time he has had a son in his racing team. Kenny Jnr raced for his father on a Yamaha, and then on the 500cc two-stroke Modenas KR3. "Little Kenny" went on to win the 500cc World Championship in 2000, riding a Suzuki.

Kenny Snr said: "Kurtis is talented and he is maturing quickly. When you have talent and once you get maturity, you're ready for GP racing. But he will have to up his game. When I came to Europe as a rider, I also had to get faster. That happens when you come into an arena with more and better competition. I think he's ready for it."

This season Kurtis and Nobuatsu will compete on the second-generation Proton KR V5. The original engine, fully designed in house at Banbury, has been upgraded, and an all-new chassis, incorporating techniques from F1 racing, should take the project another step forward for its second season.