Complex sentence: This is the only small twin with a longer stroke than 3.8125, which is otherwise universal to the entire 45/K/Sportster line from 1929 to the present (exception: XR750, XB9 Buell).
Split into simpler sentences: This is the only small twin with a longer stroke than 3.8125. The shorter stroke is otherwise universal to the entire 45/K/Sportster line from 1929 to the present (exception: XR750, XB9 Buell).