Model W
... that the flat-twin in the 1919–1923 Model W was Harley-Davidson's first flathead engine?
... that the <a href="./Flat-twin_engine" id="mwAgs" rel="mw:WikiLink" title="Flat-twin engine">flat-twin</a> in the 1919<span id="mwAgw" typeof="mw:Entity">–</span>1923 <b id="mwAg0"><a href="./Harley-Davidson_Model_W" id="mwAg4" rel="mw:WikiLink" title="Harley-Davidson Model W">Model W</a></b> <i id="mwAg8">(pictured)</i> was <a href="./Harley-Davidson" id="mwAhA" rel="mw:WikiLink" title="Harley-Davidson">Harley-Davidson</a>'s first <a href="./Flathead_engine" id="mwAhE" rel="mw:WikiLink" title="Flathead engine">flathead engine</a>?