SELECT
       customerName
FROM
     orders  JOIN customers
WHERE
      orders.customerNumber=customers.customerNumber
AND
      orders.orderNumber IN(
        SELECT
               orders.orderNumber
        FROM
             orderdetails JOIN orders
        ON
              orders.orderNumber=orderdetails.orderNumber
        AND
              orderdetails.productCode IN(
                SELECT
                       products.productCode
                FROM
                     products JOIN orderdetails
                ON
                  products.productCode = orderdetails.productCode
                AND
                  products.productLine='Motorcycles'
                      )
       );