documentclass{moderncv}

usepackage{moderntimeline}
moderncvtheme{classic}
tlmaxdates{2007}{2012}

setlength{separatorcolumnwidth}{0.25textwidth} % 0.025 <=============

firstname{John}
familyname{Doe}


begin{document}
tlcventry{2010}{0}{I'm still doing this!}{}{}{}{}
tlcventry{2009}{2010}{Then I did something else.}{}{}{}{}
tlcventry{2009}{2009}{I did something cool for just one year.}{}{}{}{}
tlcventry{2007}{2009}{A regular entry}{}{}{}{}
end{document}