• Yamaha introduced its first Big Bear utility quad in 1987, a make that was still around in 2010. It was the corporation's first ATV with four-wheel drive, a feature gave the quad extra power. In 2001, a 400 cc Big Bear was available with either both four- or two-wheel drive. Engineering specs were otherwise the same for these models.
  
  

Engineering

• The 2001 Big Bear featured a four-stroke, forward-inclined single cylinder engine with a single overhead camshaft design. The engine had a displacement of exactly 386 cc (23.56) cubic inches, a bore and stroke of 3.27 by 2.81 inches, and a compression ratio of 8.6 to 1.0.
  
  

Systems

• Equipped with a wet sump lubrication system and electric recoil starter, the '01 Big Bear also featured a Mikuni BTM32SH carburetor and a wet, centrifugal automatic clutch. The constant-mesh, five-speed transmission came with a spur gear primary reduction system and a shaft drive secondary system.
  
  

Chassis and Suspension

• The 2001 Big Bear 2x4 was built on a steel-type frame and had a caster angle of 2.5 degrees and a 0.59-inch trail. A double wishbone suspension protected the front, while a swingarm or monocross suspension came equipped in the rear. A coil spring/oil damper shock absorber was also found in both front and back.
  
  

Brakes and Tires

• Dual-disc brakes came equipped in the front of the '01 Big Bear, operated by the driver's right hand. In the rear, drum brakes could be operated by left hand and right foot. The quad took two different sizes of tires: AT25x8-12 in the front and AT25x10-12 in the back.
  
  

Measurements

• The 2001 Big Bear weighed 630.5 pounds. It measured 77.0 inches in length, 45.5 inches in width, and 45.0 inches in height. The seat height measured 32.9 inches, the ground clearance was 8.5 inches and the wheelbase measured 47.6 inches. The quad needed at least 137.8 inches to turn. It had a gas tank capacity of 3.6 gallons.