Yamaha USA first offered an all-terrain vehicle, or ATV, in 1980 when it introduced the three-wheel Tri-Moto. By 1984, Yamaha's first four-wheeler, the YFM Moto-4 was in full production. Starting out with 80- and 200-cc models, the YFM 350 Moto-4 was introduced in 1987. The YFM-350ER is the designated Moto-4 model, lasting from 1987 until 1995, before becoming various named models, including the Warrior, Raptor Big Bear and other YFM designations. Identification is accomplished by locating and decoding the Vehicle identification Number, or VIN. All Moto-4 models have this standardised code stamped on the frame.
Locate the Yamaha VIN. While sitting on the vehicle, the VIN is stamped on the left side of the frame. From year to year, the specific location may change, with common locations being: between the engine and the A-arm, about 6 inches back, on the neck of the frame near the triple-tree, or slightly forward of the front left foot peg. The frame may need to be cleaned with a wire brush for the VIN to be visible.
Identify the Yamaha VIN. According to ATVStyle.com, positions four through eight are the model designation code. Entering the complete 17-position VIN
on a Yamaha VIN decoder, similar to the one found on Motoverse (see Resources), will identify the YFM-350ER.
Identify the year of manufacture. Position 10 designates the model year, and according to ATVStyle.com, the year codes begin with "H" for 1987 and follow in sequence to "S" for 1995, skipping both the letter "I" and "O."