Pierre Trudeau's Harley-Davidson

 a 1947 EL1000 Knucklehead

Did you know Pierre Trudeau owned and rode a motorcycle in Europe after the war?  On page  47 of Volume 2 of Trudeau and Our Times by Christina McCall & Stephen Clarkson, there is this sentence referring to his time at the London School of Economics in 1947.

When Trudeau failed to turn up in the graduate common room the standing joke among his fellow Canadians was that he must be off to Paris on his big scarlet Harley-Davidson, a prospect that made them wildly envious, living as they were on tight budgets in the dingy digs available to students in austerity-locked London. 

The most likely candidate is a 1947 H-D 1000 EL with the famous 'knucklehead' motor. The name refers to the valve cover which has the shape of a fist. The picture I've used is from this site and the bike belongs to Ron M. of North Vancouver.  Here's another for comparison, and a video of one running.

I was exactly 15 years behind him riding a bike from London to Paris (this one) but I didn't do it on weekends, didn't attend the LSE and I didn't ruin the country.