I was actually handed a Vincent Rapide in the Blue Ridge Mountains and told to "ride it back to the barn" ... which was about 60 miles of mountain roads.
I started it twice, and it started instantly on one kick.
Since it's a twin, you do NOT start it like a big single. You get the carbs tickled (or, if it's hot, the throttle cracked), you pull the decompressor lever in, give it a big kick, and HALFWAY THROUGH THE KICK, you let off the decompressor, and the next cylinder to get to TDC on the compression stroke fires off and there she goes.
A barrel of fun to ride, a Vincent twin!