Harley Davidson (HOG - Get Report) will begin offering rebates on its 2016 motorcycles to retailers in the U.S. as an incentive to get them to shift a backlog that has limited sales of its latest motorcycles, Reuters reports.

Dealers are expecting the rare promotion to run until the end of this month and will likely pressure the company's margins for the first half of the year.

Demand for Harley's in the U.S. has slowed as baby boomers, the company's most loyal customers, age and competitors offer less expensive options, Reuters noted.