Builder Les Long of Cornelius, Oregon made a horizontally-opposed, two-cylinder engine using cylinders, pistons and connecting rods of a Harley-Davidson Model 74 engine, and  he personally built the rest of it.

-This engine was known by the name of "Harlequin" and more colloquially "Long Harlequin". Perhaps because he was part of Harley, Harle-quin.

-It was in the years 1933-35. It had simple ignition and gave 30-35 hp at 2,850 rpm.

“Long Harlequin”

From appendix 10: Sometimes “Les Long”. Below we show two more pictures of this engine.

"Other viewing angles of the Long Harlequin"

From Appendix 11: This engine has been used on the Harlequin Longster aircraft.