Yamaha models can be identified by locating and decoding the crankcase engine number. Yamaha uses a standardized numbering system, which is broken into four sections: model code, basic part number, design code and the finish code. Because the crankcase engine number is actually the part number, improper identification might occur if the engine has been replaced, or if an interchangeable case has been swapped with the original. According to Tangedal.no, the first section of the part number identifies the Yamaha model. Locate the engine number. Yamaha engine numbers normally are located on the top of the crankcase, next to the clutch cover on the right side of the engine while sitting on the vehicle. Write this number down for referencing.
According to Tangedal.no's Yamaha part structure PDF, the first three positions of the 12-position code designate the model and is either alpha-numeric or all digits - 2A0, for example. Look the model number up on a Yamaha model listing. A listing similar to the ones found on Off-Road and Net Bikes.com should be consulted to properly identify the model.
The model year is included within the code, as each year is assigned a different code unique to the year of manufacture. Off-Road.com is primarily a dirt bike/off road reference, Net Bikes references street models.
Yamaha serial numbers are recycled every ten years, 29 formats are supported here based on research available on the yamaha website. There is some overlap between formats and in those cases multiple results will be generated.