The most common location for a vehicle identification number on a motorcycle or a dirt bike is the steering neck, according to MotoSport. An alternative location is on the motor at the bottom of the cylinders. The number is normally etched vertically on the steering neck.
Several vehicle-related documents also normally have the VIN number, according to MotoSport. Car registrations, titles and insurance cards all normally contain the number, which is 17 characters long. One way to spot a VIN on a motorcycle is to turn the handlebars to the left and look for the etching on the frame's right side.