Harley-Davidson (HOG) is a true American icon. Its motorcycles are so distinctive that the company actually tried to trademark the “Harley sound,” that familiar rumble of the bikes’ exhaust, back in the mid-1990s.

It’s also a well-managed company and one of those true rarities: a successful turnaround story. This is a company that was facing bankruptcy in the early 1980s, yet managed to rebuild itself into the pride of American manufacturing … and it’s the subject of countless case studies in MBA programs worldwide.

Harley’s management was able to pull off the coup by leveraging that intangible quality that is so hard to imitate: brand cachet. For a particular breed of leather-wearing motorcycle enthusiast, there is simply nothing on par with a Harley.

But all of that said, I wouldn’t touch Harley stock … at least not at today’s prices.

Harley-Davidson (HOG): Worth the Premium?

At first glance, HOG would appear only modestly overpriced. It trades for 20 times trailing earnings and 2.5 times sales, compared to 19 and 1.6, respectively, for the S&P 500.

A modest premium might be appropriate for an iconic company with Harley’s branding power (and not to mention its high return on equity of 26.1%). But consider that Daimler (DDAIF) — a company that knows a thing or two about vehicle branding — trades for just 10 times trailing earnings and 0.60 times sales.

Yes, I realize it’s not an apples-to-apples comparison and that Harley runs a higher-margin operation in a business with fewer direct competitors. All else equal, Harley should trade at a slight premium to a larger automaker like the current Best Stocks of 2013 leader.

But all else is not equal.

Harley has a serious growth problem, and it’s not one that will go away with a recovering economy.

Harley’s revenues still are below their pre-crisis highs (see Figure 1), and unit sales paint an even bleaker picture. Harley sold 349,196 bikes in 2006, and sales dropped to just 247,625 in 2012. That’s a unit decrease of nearly 30%!

To be fair, revenues and unit sales have enjoyed a nice bounce since the pits of the financial crisis. But Harley will never get its old mojo back for one critical reason that is completely outside of its control.

Demographics

Down the road from my house in Dallas, there is a greasy drive-in burger joint called Keller’s. On any given weekend, you might see a dozen or more bikers parked in the lot, showing off their chrome-laden Harleys.

Most are over 50. Nearly all of them are older than 45.

This isn’t a coincidence. Harley-Davidson is a brand whose sales depend disproportionately — almost exclusively, in fact — on middle-aged Caucasian males. Riders younger than 40 generally lack the time, interest or the bankroll to buy a Harley. But by the time they get into their 60s or older, the noise and joint pain have whittled at riding’s allure. You still might ride in your 60s, but you’re doing it less frequently and you probably aren’t buying a new bike.

The sweet spot is the mid-40s to early 50s. And with the Baby Boomers — the largest and wealthiest generation in history — now largely aged out of this key demographic bracket, Harley has a serious problem.

Generation X — my generation — is not nearly large enough to pick up the slack, and Generation Y (aka “the Millennials” or “Echo Boomers”) are decades away from being in the demographic sweet spot for Harley … and this assumes they take to riding like their dads did. The number of American men aged 40-49 is set to decline through the early 2020s and won’t reach its old 2010 peak until 2035 (see Figure 2).

CNN Money reported on this as far back as 2010, and demographic strategist Harry Dent — my old boss — has used Harley as a case study for decades.

Harley-Davidson management is not stupid. It understands the issues the company faces, and HOG’s leaders have gone so far as to address it with a dedicated page on their Investor Relations site: Harley-Davidson Demographics.

Stop and think about that for a minute. Have you ever seen a company dedicate prime website real estate to the demographics of their customer base? I haven’t. But then, few companies face the severe demographic issues that Harley does.

The company has aggressively expanded its marketing efforts to attract younger men, non-Caucasian men, and women, to modest success. Per the demographic site, management writes:

“In 2012, U.S. sales of new Harley-Davidson motorcycles to our ‘outreach’ customers — young adults 18-34, women, African-Americans and Hispanics — grew overall at more than twice the rate as sales to our traditional U.S. customer base of Caucasian men, ages 35-plus.”

But realistically, there is no replacing white Baby Boomer men. And this means a very rough decade ahead for Harley-Davidson stock holders.

Bottom Line

Stocks in gently declining industries are not necessarily bad investments, as tobacco stock investors have no doubt noticed.

Under the right set of circumstances — strong financial health, large barriers to entry, good dividend growth and share buybacks — stocks in no-growth industries can make better investments than those in high-growth industries.

But for this to be the case, the stock has to be priced appropriately. Big Tobacco has had a great decade-long run because it started out cheap and paid a monster dividend. HOG, in contrast, trades at a slight premium to the market and yields only 1.3%.

Harley-Davidson stock might be a good buy … eventually. But given the demographic headwinds it faces, it’s not cheap enough for serious consideration at this time.

An intrepid investor might even consider HOG as a short.

Charles Lewis Sizemore, CFA, is the chief investment officer of the investment firm Sizemore Capital Management. As of this writing, he was long DDAIF. Click here to receive his FREE 8-part investing series that will not only show you which sectors will soar, but also which stocks will deliver the highest returns. This series starts Nov. 5 and includes a FREE copy of his 2014 Macro Trend Profit Report.