Is "Harley machine" really a phrase used for a Harley-Davidson motorcycle?
Solution 1:
Dictionary.com defines as “old“ the use of the term machine for the following items:
1)an automobile or airplane.
2)a typewriter.
3) a bicycle or motorcycle.
From : Harley-Davidson: The Good, the Bad, and the Legendary by Voyageur Press
The first Harley was sold before it was finished to a local man named Meyer, who put 6,000 miles (9,654 km) on the machine before selling it to a George Lyon, who added 15,000 miles (24,135 km).
Motorcycle:
Dual purpose machines like the dual-sport style are made to go off-road but include features to make them legal and comfortable on the street as well
(Wikipedia)
So, the expression “Harley machine” though dated, is correct.