* Champion Lorenzo crashes out while leading
* Pedrosa wins his seventh race of the season
* Stoner third in final race before retiring (Adds quotes, details)
VALENCIA, Nov 11 (Reuters) - World MotoGP champion Jorge Lorenzo was denied a victorious season finale on home soil when he crashed out while leading an incident-packed Valencia Grand Prix on Sunday to hand victory to fellow-Spaniard Dani Pedrosa.
Yamaha rider Lorenzo, who clinched his second world title two weeks ago at Phillip Island off Australia, lost control of his machine with around 17 laps remaining and catapaulted off the track to leave Honda's Pedrosa with a comfortable lead over Briton Cal Crutchlow in third.
Lorenzo was able to walk away from the accident and did not appear to have sustained any injuries.
Crutchlow crashed with seven laps left and Pedrosa cruised to his seventh win of the year, one more than Lorenzo, almost 40 seconds ahead of Japanese Yamaha pilot Katsuyuki Nakasuga, standing in for injured American Ben Spies, in second.
Pedrosa's Honda team mate Casey Stoner, in the Australian double world champion's final race before retiring, pipped Yamaha's Alvaro Bautista to third a further 23 seconds back.
In a chaotic start to the 18th and final race of the season, several riders including Pedrosa had to change to bikes with slick tyres after they realised on the warm-up lap that the track was quickly drying out after a damp morning.
Lorenzo already had his slick tires and raced into an early lead before Pedrosa, who had started from the pit lane after the tire change, climbed more than 15 positions in only seven laps and hauled him in.
"It was quite exciting at the start as some riders had slicks and others had wet tires," Pedrosa said in an interview with Spanish television.
"When we did the warm-up lap I realised I needed the slicks," he added. "I have never started from the pit lane before and I was full of doubts.
"I made a mistake when I was right behind Jorge and then he made one himself. It's fantastic to win the last race."
The Honda mechanics paid tribute to Stoner as he crossed the line and hung out a sign reading "Going fishing" for the 27-year-old, a possible hint of how he may fill some of his time after falling out of love with the sport.
Stoner told Spanish television he had ridden a careful race as he was worried about hurting the foot he damaged in Indianapolis in August.
"We went way too late to the slick tires but we brought it home and got on the podium and there are a lot worse ways to end my career," he said.
"I want to thank my team, all my supporters for all these years, all my sponsors. I'm a little disappointed not to be able to win this race."
Lorenzo tops the final championship standings with 350 points, with Pedrosa in second on 332 and Stoner on 254.
In the Moto2 category, champion Marc Marquez, who will replace Stoner at Honda next season, charged from last on the grid to win ahead of Spanish compatriots Julian Simon and Nico Terol.
Briton Danny Kent took victory in Moto3 ahead of Italian champion Sandro Cortese and Zulfahmi Khairuddin of Malaysia. (Writing by Iain Rogers in Madrid, editing by John Mehaffey)