The Big Bear 350 is an all terrain vehicle, or ATV, developed by Yamaha Motor Company. When it first hit the market in 1987, with a red and white colour design, the ATV was Yamaha's first venture into the world of quads. The Big Bear 350 ran until 1999, but over its course, it only saw minor modifications. Most of these changes appeared in the 1997 two-wheel drive and 4x4 models.
At the heart of the Big Bear is a four-stroke engine. This means that in every rotation of the crankshaft the intake, compression, power and exhaust stroke takes place. It has a displacement -- the volume swept by the pistons in a movement from top dead centre to bottom dead centre -- of 21.3 cubic inches. The engine's cylinders are 3.3 inches in diameter, known as bore. Pistons travel 2.5 inches within the cylinders, known as stroke. A single overhead cam design places the camshaft within the cylinder heads and above the combustion chamber. This has fewer components than an overhead valve design, meaning it weighs less. A Mikuni BTM32SH carburettor delivers the fuel to the engine. Taking the engine's power and delivering it to the wheels is a five-speed transmission system with reverse and chain drive. This ensemble is kicked of via an electronic starting system with recoil.
Front and back wheels that are 12 inches wide sit beneath a 47.6-inch wheelbase. Wheelbase is the distance between centre of the rear wheel and the centre of the front wheel. The bottom of the frame clears the ground by 7.1 inches. In 1997, a lightweight chassis was fitted in the 4x4, improving the maneuverability of the vehicle. In addition, in this year, a two-wheel drive version of the Big Bear 350 was introduced. This model could carry 120 Kilogram and tow 410 Kilogram using a trailer hitch.
When the vehicle is in motion, it is the job of a double wishbone front suspension system to smooth out the bumpier roads. Double wishbone uses two arms, each arm joins to the chassis at two points and there is one joint at the knuckle. At the back there is swing arm suspension used to securely grasp the axle while pivoting. This includes one shock absorber. Two hydraulic drum brakes at the front of the vehicle bring the Yamaha to a halt, accompanied by one mechanical drum brake at the rear. The turning was made tighter in both the 1997 4x4 and two-wheel drive models. The two-wheel drive 1997 version added an automatic clutch, wider foot pegs and extra padding in the seats. It also added a moss green colour design. The four-wheel drive from 1997 came in both green and grey.