Preview - Valencia Grand Prix.

The MotoGP season reaches a fitting climax in the frenzied atmosphere of the Valencia Grand Prix at the Ricardo Tormo circuit in Spain on Sunday.

A weekend crowd of over 200,000 will pack the grandstands around the 2.489-mile circuit on the outskirts of Valencia to witness the continuing battle between world champion Valentino Rossi and the pretenders to his championship crown, Marco Melandri and Nicky Hayden.

Rossi has won for the last two years in Valencia - on both Honda and Yamaha machinery - and is seeking a hatrick of victories, riding the Gauloises Yamaha, in the 30-lap race on Sunday to secure his 12th grand prix victory of the year. A win this weekend would also put Rossi equal with Mick Doohan's all time season win record.

But the Italian knows it will not be easy with Melandri, who won the 2002 250cc race in Valencia, riding on a high after his first ever MotoGP win last time out in Turkey.

Melandri's victory on the Movistar Honda has given him an eight-point lead over Hayden in their battle for second place in the championship after the American, riding the Repsol Honda, finished third in Turkey.

Mathematically, Colin Edwards could still finish second in the title chase, but Rossi's Yamaha team-mate would have to win his first MotoGP race to have any chance of Yamaha claiming a dream one-two in the company's 50th anniversary year. Speaking of which, will Valencia see Rossi and Edwards running a special 50th anniversary livery? Watch this space...

Meanwhile, Max Biaggi, who holds the lap record at Valencia, looks likely to end his wretched season with Repsol Honda in fifth place, 13 points in front of an equally dejected Sete Gibernau. The Roman looks set to rejoin Camel Honda next year, but some sources are saying that Honda doesn't want to work with him - even as a satellite rider...

Spaniard Gibernau has also endured a tough season - and is yet to win a grand prix this year. How he would like to repeat his emotional victory of four-years ago on his last ride for Movistar Honda before his likely move to Ducati Marlboro.

Former 125 and 250cc world champion Loris Capirossi makes a welcome return to the factory Ducati team after missing the last two races because of injury. He got the OK after a scan on his damaged lung on Saturday and will be hoping to hit the form that brought him victories in both Japan and Malaysia a couple of months ago.

Capirossi's current team-mate, Carlos Checa, will be making his last appearance for the Ducati team and will be seeking to end on a high note after an impressive finish to the season.

Makoto Tamada set pole last year but he has had a tough year on the Konica Minolta Honda while young Spaniard Tony Elias is beginning to impress on his MotoGP debut season after finally recovering from a serious wrist injury.

Shinya Nakano won the 250cc race five years ago and in Turkey agreed a new MotoGP contract with Kawasaki. The Japanese will be partnered for the final time in Valencia by Alex Hofmann, who will return from injury for his Kawasaki farewell ride.

Other riders who could be making their final MotoGP appearances with Ruben Xaus, Olivier Jacque and perhaps even Alex Barros bowing out after this weekend. One man definitely not in MotoGP next year is Camel Honda's Troy Bayliss, who has already signed for the Ducati Xerox team in World Superbike.

Bayliss had been hoping to return from a wrist injury to make his MotoGP farewell, but will not be making the trip to Spain and his place alongside Barros has now been given to BSB runner-up Ryuichi Kiyonari.

Shane Byrne, who began the season with Team Roberts until the withdraw of KTM engines forced his own departure, had been hoping to make his third Pons appearance of the season - Chris Vermeulen having already been ruled out after signing for Suzuki - but a last minute Honda decision saw Kiyonari get the ride instead.

Meanwhile, after missing the last five grands prix, Team Roberts will return to MotoGP action in Valencia where 2004 race rider Kurtis Roberts, youngest son of team principle and three times 500cc champion Kenny, will steer the team's Proton KR V5.

In the 250cc class, 20-year-old Spaniard Dani Pedrosa bows out of championship after dominating for the last two years. He joins MotoGP next year riding the Repsol Honda and will want to celebrate his 2005 World title in front of his home crowd and depart with a victory on Sunday.

But Australian Casey Stoner could well spoil the party after winning three of the last four races, riding the Carrera Sunglasses-LCR Aprilia. The 20-year-old is in tremendous form and could also be heading for a MotoGP ride with Yamaha next year.

Pedrosa won the race last year while Randy De Puniet took victory in 2003. The Frenchman also makes his final 250cc appearance in the 27-lap race after signing a contract with Kawasaki to move up to MotoGP.

Swiss teenager Thomas Luthi is on the verge of capturing the 125cc World Championship in the final round. He holds a 23-point lead over the KTM of Mika Kallio going into the 24-lap race and the Honda rider only has to finish 13th to ensure his first World title even if Kallio wins the race.

It will be a tense afternoon for his Elit Grand Prix team hoping their man will keep out of trouble because if he failed to finish and Kallio won the race, it would be the Finn who won his first world championship.