Only the dirt bike's 17-digit VIN can be used to identify and register ownership of the dirt bike. The engine number contains 11 characters as opposed to the VIN's 17 characters, so when buying a used dirt bike without paperwork (never a good idea!), don't let the seller use the engine number on a Bill of Sale. The dirt bike engine number is an 11 digit identifier usually located on the right side of the engine case near the kickstarter (or where the kickstarter used to be if the bike has e-start). The image below shows the area to check for the dirt bike VIN: Engine number vs. The VIN should be etched into the frame and should not be altered or defaced in any way. The handlebar stub is the short piece just above where the front fork is mounted on the frame and is right behind the front number plate. The VIN on a dirt bike is usually located on the right side (as you're sitting on the bike) of the handlebar stub. The rest of the characters (11-17) denote the assembly plant, production number, and available options. The all-important (for dirt bikes without paperwork) 10th character indicates the marketing year of the vehicle. These characters are referred to as the Vehicle Identifier. Characters 10 - 17 (Vehicle Identifier Section):.Character Nine is a check digit that's used to make sure the VIN is correct. This group of characters describes things such as model, engine size, and various style options. Characters 4 - 9 (Vehicle Descriptor Section):.The first character indicates in what region the dirt bike was manufactured, the second character when combined with the first character narrows the manufacturing region ever further, indicating in which country the bike was manufactured, and the third character is used to identify the vehicle type. Characters 1 - 3 (World Manufacturer Identifier):.Most of the VIN info relates to cars, not dirt bikes, but here's a quick VIN decoder explanation: In 1981 the NHTSA (National Highway Traffic Safety Administration) instituted the VIN system which is a 17-character alphanumeric identifier and the VIN is now etched into the dirt bike's frame.
Prior to 1980 most dirt bikes had a metal tag stamped with a serial number of about eight or ten characters (depending on the year and model of the bike) riveted somewhere on the bike's frame. Making sure the dirt bike isn't stolen is the other part, and the dirt bike's VIN (Vehicle Identification Number) can help determine if the used dirt bike you're buying is legit. Buying a used dirt bike in good mechanical condition is only part of the total equation. You've worked hard for your money and the last thing you want to discover is that the used dirt bike you just bought was stolen.