In 1985, Yamaha Motors introduced their first ever recreational all-terrain vehicle, or ATV. Today, Yamaha's original ATV design has evolved greatly to include hundreds of different features and models. All Yamaha ATVs have a 17-digit vehicle identification number on them that you can use to identify characteristics such as the year, model and other valuable facts that pertain to the ATV.
Locate the VIN number on the frame of the ATV. This number is usually found near the front end of the vehicle on the left side under the shift lever. The title of the ATV will also have the VIN number on it.
Check to make sure that the second letter of the VIN is a "Y". If not then your ATV is not a Yamaha at all.
Look at the fourth through the eighth characters. These numbers will tell you the model, body style and engine type. To decode these numbers, use a Yamaha VIN decoder (such as the one in Resources) or look in your owner's manual.
There are many VIN decoders available online that will tell you everything about the ATV.