The sound of a bike stirs your soul as much as the ride.
The soft phut-phut of a Royal Enfield Bullet 500, for example, has always felt like the hearbeat of India since I rode one from there back to the UK in 1998.
The syncopated beat of a Harley V-twin, like two flatulent hippos making love underwater, always brings me back to riding a Road King on Route 66 from Chicago to Los Angeles two years later.