Model O
... that in 1919, the year Indian discontinued its Model O flat-twin motorcycle, Harley-Davidson introduced a flat-twin motorcycle?
... that in 1919, the year <a class="mw-redirect" href="./Indian_(motorcycle)" id="mwB7k" rel="mw:WikiLink" title="Indian (motorcycle)">Indian</a> discontinued its <b id="mwB7o"><a href="./Indian_Model_O" id="mwB7s" rel="mw:WikiLink" title="Indian Model O">Model O</a></b> <a href="./Flat-twin_engine" id="mwB7w" rel="mw:WikiLink" title="Flat-twin engine">flat-twin</a> motorcycle, <a href="./Harley-Davidson" id="mwB70" rel="mw:WikiLink" title="Harley-Davidson">Harley-Davidson</a> introduced a <a href="./Harley-Davidson_Model_W" id="mwB74" rel="mw:WikiLink" title="Harley-Davidson Model W">flat-twin motorcycle</a>?