Shares then pared gains after a company spokesperson said the company was not "aware of" anything specific that boosted the shares about 6.8 percent. At midday Harley shares were up about 3 percent.
"We don't comment on rumors," Maripat Blankenheim, Harley-Davidson spokesperson said. "Those kinds of rumors happen every now and again."
Earlier this year Harley shares surged 17 percent on takeover speculation.
(Reporting By Meredith Davis in Chicago; Editing by Andrew Hay)