Oct. 29 (Bloomberg) -- Honda Motor Co., Japan's second- largest carmaker, jumped the most in at least 34 years, leading gains by automakers after the yen declined against the dollar and euro, boosting earnings from exports.

Honda rose as 18 percent, or 375 yen, to close at 2,440 yen in Tokyo. Earlier in the day, the stock rose by 400 yen, the daily trading limit. Mazda Motor Corp., a third owned by Ford Motor Co., rose 13 percent, the most in eight years, to 198 yen.

The yen was at 123.36 per euro after dropping 7.3 percent yesterday, its biggest decrease since the 15-nation euro's 1999 debut. A weaker yen inflates the value repatriated earnings from Europe and the U.S.

``The yen weakening helps the carmakers,'' said Hideyuki Suzuki, a market analyst at Morningstar Japan K.K. in Tokyo. ``The market is rebounding from its earlier losses.''

Toyota Motor Corp., the country's largest carmaker, gained 10.4 percent. Nissan Motor Co., Japan's third-biggest automaker, and Isuzu Motors Ltd., Japan's largest maker of light-duty trucks, both surged 11 percent.

To contact the reporter on this story: Makiko Kitamura in Tokyo at mkitamura1@bloomberg.net.

Last Updated: October 29, 2008 02:39 EDT