WASHINGTON - Sarah Palin rumbled through Washington on the back of a Harley as she and her family began an East Coast tour on Sunday, renewing speculation that the former Alaska governor would join the unsettled Republican presidential contest.

Wearing a black leather jacket and surrounded by cheering fans, Palin and family members jumped on bikes and joined thousands of other motorcyclists on the Memorial Day weekend ride from the Pentagon to the Vietnam Veterans Memorial.

Palin didn't mention politics as she visited with participants, but she smiled broadly when many in the crowd urged her to run.

When one man asked her if she was running, she smiled and answered, "Don't know."

According to the Harrisburg Patriot-News, she and her family stopped in Gettysburg yesterday afternoon, after earlier visiting Mount Vernon, in Virginia, and Fort McHenry, in Baltimore.

Palin remains one of the biggest questions for Republicans, who have not yet settled on a front-runner to challenge President Obama's re-election. While many of Palin's likely rivals have worked to build campaign organizations in early nominating states such as Iowa or New Hampshire, Palin has taken no concrete steps to begin a presidential campaign.

Given Palin's star power, she might be able to wait longer than others. But the clock is ticking, the establishment isn't happy with its options and one of the earliest tests of campaign infrastructure, the straw poll in Ames, Iowa, is set for August.

Palin showed no hints Sunday that she would join the field, although she again demonstrated her ability to build excitement and practice the person-to-person, retail politics that she clearly loves.

In heels and black flare slacks, Palin shook hands and posed for pictures with well-wishers.

"How do you wear all this leather and stay cool?" she asked one woman. Palin asked others to show off their tattoos as she took off her own leather jacket and worked her way through a crush of fans, photographers and reporters.

Palin, whom Sen. John McCain elevated from an obscure governor to national star, set off from Washington on a tour of East Coast historical sites. Her political committee billed the swing as an opportunity for her family to visit historic sites as they worked their way to New England.

Palin's trip set off speculation that she would visit New Hampshire, the state that holds the first nominating primary and a place Palin hasn't visited since the final days of the 2008 campaign.

Many of Palin's potential rivals were set to visit New Hampshire in the coming week, including another tea-party favorite: Rep. Michele Bachmann of Minnesota. Former Massachusetts Gov. Mitt Romney was expected to make formal his bid during a noon barbecue on Thursday. Former New York Mayor Rudy Giuliani was to speak at a fundraiser for the state GOP.

Former Utah Gov. Jon Huntsman - who also rides motorcycles - is spending the weekend working through the state's rural North Country.

And former Minnesota Gov. Tim Pawlenty visited New Hampshire last week, just days after he formally declared himself a candidate while in Iowa.

Former House Speaker Newt Gingrich also campaigned in a state that is emerging as a linchpin for many of the campaigns already rolling.

Yet others could still enter the race.

Texas Gov. Rick Perry on Friday hinted that he could start campaigning for a job he once ruled out.

Former New York Gov. George Pataki is running television ads in New Hampshire and speaking out against Obama.

New Jersey Gov. Chris Christie has insisted he's not running; his supporters don't believe him.

Should Palin run, she'd have to leave Fox News Channel's lucrative payroll.

Should she come up short of the nomination, she'd lose some of her cachet.

And this weekend proved she can create buzz without being a candidate.