Passage: Harley-Davidson's association with sportbike manufacturer Buell Motorcycle Company began in 1987 when they supplied Buell with fifty surplus XR1000 engines. Buell continued to buy engines from Harley-Davidson until 1993, when Harley-Davidson bought 49 percent of the Buell Motorcycle Company. Harley-Davidson increased its share in Buell to ninety-eight percent in 1998, and to complete ownership in 2003.In an attempt to attract newcomers to motorcycling in general and to Harley-Davidson in particular, Buell developed a low-cost, low-maintenance motorcycle. The resulting single-cylinder Buell Blast was introduced in 2000, and was made through 2009, which, according to Buell, was to be the final year of production. The Buell Blast was the training vehicle for the Harley-Davidson Rider's Edge New Rider Course from 2000 until May 2014, when the company re-branded the training academy and started using the Harley-Davidson Street 500 motorcycles. In those 14 years, more than 350,000 participants in the course learned to ride on the Buell Blast.On October 15, 2009, Harley-Davidson Inc. issued an official statement that it would be discontinuing the Buell line and ceasing production immediately. The stated reason was to focus on the Harley-Davidson brand. The company refused to consider selling Buell. Founder Erik Buell subsequently established Erik Buell Racing and continued to manufacture and develop the company's 1125RR racing motorcycle.

Question: What was the first exchange between Harley-Davidson and Buell?
fifty surplus XR1000 engines