Yo. LongJohnSilver here. I enhanced the contrast on the picture which helped (I suggest you try that too).
My guess would be this baby here: a 1946 Triumph Speed Twin - sans front fender, of course, which probably got
packed with snow between the tyre & fender, thus its temporary removal for winter sport! :O)
Aside from the Triumph style vertical twin engine, I see LOTS of little clues that this is it:
the headlight - size & distinctive mount, the little flat hockey-puck shaped speedo (?) to the left rear of the headlight,
the triple stage painted front forks, the crossbar between the forks under the headlight, the very unique tank paint job
with the chrome inner area and the large painted surface (though "Triumph" is not legible), the megaphone mufflers, etc.
http://www.vintagebike.co.uk/Bike%20Directories/Triumph%20Bikes/pages/Triumph%20Speed%20Twin%201946.htmHope this helps!
Johnny Long - London (03 H-D FLHRCI)