VALENCIA, Spain - The memory of Marco Simoncelli and the appalling crash that took his life in Sepang will hang heavy over the season-ending Valencia MotoGP this weekend.The young Honda rider's death in the horror crash in Malaysian has cast a pall of gloom on the sport as the curtain falls on the 2011 campaign.LAST START FOR CAPIROSSIUnder normal circumstances - and with the MotoGP title already claimed by Casey Stoner - another Italian, Loris Capirossi, could have hoped to have been the focus of attention as the veteran will retire after Valencia with 22 years of World Championship action behind him.Former 250cc World champion Capirossi, aged 38, will make his 328th and final GP start and says he and his fellow racers are determined to pay a fitting tribute to Simoncelli."It will be difficult to be in the paddock without Marco," he said, "as everyone will miss him. Nobody will feel like going on the track, but we have to do it for him and for all fans of motorcycle racing."It will be my final race and I don’t know what will be going through my head but I want to do it as well as possible."Team mate Randy de Puniet added: "It will be really difficult to race at Valencia without Marco but part of our job is to continue."Despite the deep mourning the sport has been in since the tragedy the Italian's Gresini Honda manager Fausto Gresini said the show must go on - and that Simoncelli would not have wanted it any other way."The decision was not easy but we made a choice - we think that's what Marco would have wanted," Gresini added. "Putting our wheels down on this track are the best homage we could pay to him."'RACE MUST GO AHEAD'Participants will make a special, poignant, tribute at the Ricardo Tormo circuit on Sunday morning, just after the warm-up session.Honda's Stoner agrees with Gresini that the race absolutely must go ahead. "It will be difficult to resume competing this weekend but that's without doubt the best way to honour his memory."Yamaha Tech 3 rider Colin Edwards, who along with Valentino Rossi saw Simoncelli veer right into their path at Sepang, dislocated a shoulder in the collision so will on Sunday give his ride to double Superbike champion and fellow American Josh Hayes.Australian Stoner has already taken the championship crown while Spaniard Jorge Lorenzo will finish runner-up, even though he will also miss the race (which he won in 2010) as he recovers from hand surgery after crashing in the Australian GP warm-up on Phillip Island.Replacing Lorenzo will be Yamaha test rider and All Japan Superbike competitor Katsuyuki Nakasuga who will make his second appearance in the MotoGP premier class on behalf of the 2010 World champion Lorenzo.Although the two top placings are confirmed there is still a duel for third place as only four points separate Repsol Honda team mates Andrea Dovizioso and Dani Pedrosa.AND THE OTHER RACES...Away from the MotoGp category, Sunday will see champions crowned in Moto2 and 125cc.In Moto2, Germany's Stefan Bradl will try to hold off Spanish rival Marc Marquez, who may in any case miss the race as he has been suffering vision problems since a fall in Malaysia.In 125cc, Aprilia's Nicolas Terol is on the verge of being crowned at the expense of Frenchman Johann Zarco.After the race, teams will cast an eye towards preparations for the 2012 next season from Tuesday with tests in Valencia on prototype engine development ready for the introduction of a new 1000cc engine capacity limit.