No spark for Harada.

Pole sitter Tetsuya Harada's challenge for victory in Sunday's 250cc Grand Prix ended with a broken spark plug.

The ceramic part of the 'plug' in Harada's v-twin Aprilia was damaged, robbing the Japanese star of vital revs, horsepower and any chance of victory.

"Obviously I'm very disappointed but the spark plug was broken and there was nothing I could do," said Harada, who fought to the finish despite the handicap. "I was trying to beat Katoh but now I will never know if it was possible and of course now the gap in the points is much bigger."

The Japanese veteran finished 18th and out of the points, extending Daijiro Katoh's lead in the championship to 40 points.