Harley Davidson (HOG - Analyst Report) shares became a Zacks #4 Rank Sell in early January and have since fallen 18% this year after back-to-back quarters of negative growth.

The March quarter year-over-year sales decline reported on April 21 caused the most damage as shares dropped nearly 10%. The topline came in 3% lighter at $1.673 billion vs $1.726 billion last year.

While we tend to think of Harley bikes as mostly a US domestic story, sales in China and India were the strongest ever. And the stronger US dollar apparently took its toll on the home turf too because it caused competitors to cut prices and offer aggressive rebates.

Foreign competitors especially were in a position to steal market share and may do so for some time going forward.

In fact, the company cited "increased, very aggressive competitive discounting" as the primary impetus to cut-back on its full-year shipment guidance. Preliminary projections had forecast 282,000 to 287,000 motorcycles to be shipped in 2015, but the company dropped that to 276,000 to 281,000 bikes.

Those numbers are still 2-4% unit growth, but analysts continue to trim estimates even this month as you can see in the Zacks Detailed EPS tables below...

The most recent downward revisions were what finally pushed HOG to a Zacks #5 Rank Strong Sell. Trading around 13X forward estimates now, shares seem reasonably attractive.

But given the strong dollar pressure on sales and margins, we don't yet know if estimates will come down further, or stabilize and reverse higher from these levels.

Keep one eye on the US dollar exchange rate and the other on the Zacks Rank to stay informed.