According to an Associated Press wire report, Harley-Davidson Inc.’s main ad agency of 30-plus years has dropped the motorcycle maker in favor of new business.

Ad agency Carmichael Lynch, a unit of Interpublic Group, said many factors went into the decision, including the fact that the Milwaukee-based motorcycle maker has slashed its marketing spending in recent years amid slumping sales.

Carmichael Lynch President Doug Spong also said Harley-Davidson was also never a big spender on traditional advertising. “It got to the point where we no longer felt we could take that brand forward,” Spong said.

According to Kantar Media, Harley-Davidson spent about $11 million on television ads and other measured media last year, half of its 2007 media buy.

Harley-Davidson said it will not conduct an agency review process or look to replace Carmichael Lynch.

This news comes on the heels of a 5.5 percent decline in second quarter retail sales as well as continuing union negotiations that may result in the Motor Company moving Milwaukee-area manufacturing to its Kansas City, Mo., plant.