Engineered by Yamaha for the atv motorcycle segment, the 2010 Yamaha Big Bear 400 4x4 IRS features a 421 cc (25.7 cu in) oil & air-cooled single cylinder, four-stroke configuration. Internal engine geometry specifies a bore and stroke of 83.0 x 71.5 mm (3.3 x 2.8 inches) with a 8.6:1 compression ratio.
On the scales, the Big Bear 400 4x4 IRS measures 284.9 kg (628 lbs) wet (curb). Rider ergonomics and chassis geometry center around a 894 mm (35.2 in) seat height — reflecting a long-travel chassis stance that favors ground clearance and off-pavement control, combined with a 1,229 mm (48.4 in) wheelbase engineered for quick, flickable steering geometry. The 15.14-liter (4 US gal) fuel tank supports practical everyday commuting and weekend road stints.
Within MotoLibrary's Yamaha archive, this model family spans 3 indexed model years from 2009 to 2012, allowing buyers to track year-over-year changes in emissions tuning, weight and equipment.
Standover Height
894 mm (35.2 in)
Engine
Displacement421.0 ccm (25.69 cubic inches)
Engine TypeSingle cylinder, four-stroke
Engine DetailsSingle cylinder, four-stroke
Compression8.6:1
Bore x Stroke83.0 x 71.5 mm (3.3 x 2.8 inches)
Fuel SystemCarburettor. Mikuni® 33mm BSR
Fuel ControlSingle Overhead Cams (SOHC)
CoolingOil & air
Transmission
Gearbox5-speed
Chassis
Front SuspensionIndependent double wishbone
Front Travel147 mm (5.8 inches)
Rear SuspensionIndependent double wishbone
Rear Travel193 mm (7.6 inches)
Wheelbase1229 mm (48.4 inches)
Ground Clearance267 mm (10.5 inches)
Wheels & Brakes
Front Tyre25/8-AT12
Rear Tyre25/10-AT12
Front BrakesDouble disc
Rear BrakesDouble disc
Dimensions & Weight
Weight incl.284.9 kg (628.0 pounds)
Seat Height894 mm (35.2 inches) If adjustable, lowest setting.
Overall Height1186 mm (46.7 inches)
Overall Length2017 mm (79.4 inches)
Overall Width1115 mm (43.9 inches)
Fuel Capacity15.14 litres (4.00 US gallons)
Other
StarterElectric
Color OptionsRealtree AP Camo, Hunter Green, Steel Blue
Use this page to compare this motorcycle by its real specifications, not only by model name. Focus on the details that affect fit, comfort, handling, range and ownership.
Seat Height
Check the seat height against your inseam and riding posture before choosing a motorcycle.
Fuel Capacity
Fuel capacity helps estimate touring range and how often you may need to stop.
Brakes
Brake setup is worth comparing if you ride in traffic, mountains or with a passenger.
Suspension
Suspension details can matter for comfort, road feel and long-distance riding.
Transmission
Transmission and final drive affect maintenance, smoothness and everyday usability.
