I don't know about time signatures, but there's Richard Thompson's "Vincent Black Lightning", Captain Beefheart's "Carson City", Steve Earle's "The Other Kind" & have you read "The Road" - a chapter in T.E.Lawrence's "The Mint"? Two singles echoing back off a stone-walled pass? A Benelli Sei on open Megas on a quiet duel carriageway? But, does the essence of what you're getting at have to involve motorcycles (let alone Guzzis) at all? When the first people heard Beethoven's Ninth Symphony, the internal combustion engine had not been invented. Horses. The Beat poets. Synchopation. Is the motorcycle ride just another way to get to the same place? I walked up Cadair Idris the other day.
KB