Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Shares of motorcycle kingpin Harley-Davidson (NYSE: HOG) were getting revved up by investors today, gaining as much as 13% in intraday trading on heavier-than-average volume.

So what: It's earnings season, and that means that a lot of stocks will see uncharacteristic volatility as investors react to financial reports. For Harley-Davidson, the reaction was clearly a good one as after earnings from continuing operations jumped from $0.59 per share last year to $0.81 this year. Wall Street analysts were expecting per-share profits of just $0.71. The strong bottom-line performance was driven by an 18% jump in motorcycle sales and a 35% increase in operating income from its financial services segment.

Now what: There's little doubt that Harley-Davidson sputtered a bit during the financial crisis and recession. But the company now appears to be roaring back to life with strongly rebounding sales and profits. The only drawback for investors right now is that for those of us looking at the shiny HOG shares in the window, the shares appear to already be priced for a significant continued rebound. It's hard not to notice, with a forward price-to-earnings ratio of 22.

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