2007 YAMAHA BIG BEAR 400 4X4 IRS
It’s all about the mud!"I don’t really care if a quad can fly a mile over a dune, I need something that will plow through the mud."
There are plenty of guys out there who feel this way and the engineers at Yamaha know it. That’s why they designed the ultimate mud machine.
While many ATVs on the market can handle a fair amount of mud, the guys who ride in the stuff all the time know what works best and what doesn’t. The right features on a built-for-mud machine make it safer, more reliable and less work for the owner.
So what makes a good mud machine? First of all you can forget water-cooled engines. Water-cooling means radiators that must keep a nice healthy flow of air to work. Radiators tend to pack with mud, which reduces air flow and decreases the radiator’s ability to cool the engine.
The new Big Bear is powered by a 386cc air-cooled, 4- stroke engine that puts out plenty of torque. Except for an oil cooler, which is tucked way up high, there are no coils to plug with mud.
Left:With a seat designed for moving around, riders are better equipped to handle those off camber balancing acts often experienced on the trail. Right:A combination of traction, suspension and power train components make the 2007 Yamaha Big Bear 400 4x4 IRS the ideal mud machine.
Mud packed in rear brakes can also cause a lot of grief. In some cases the brakes don’t work as well because they are glazed over from muddy water seeping in. Worse yet, corrosion can cause brakes to completely seize up, which means you’re not going anywhere (or at least stopping anywhere!)
Yamaha’s break-through brake solution is to protect the brake components from the elements by sealing them inside the rear dif. We are probably going to see these fully-sealed, oil-bath, multi-disc brakes on more machines in the future.
The next thing the mud-slinging engineers addressed was ground clearance. It doesn’t take a lot of observation to see that rear straight axles on many ATVs are the first things to drag when the ruts get deep.
Most off-roaders are familiar with ruts, which grow deeper with trail use. ATV areas are no exception, especially when you are talking about mud. In many parts of country trails have just enough room to squeeze a machine between the trees. This makes alternate lines impossible so everyone’s tires go on the same line making deeper and deeper ruts.
Yamaha’s answer to the rut problem is a new Independent Rear Suspension (IRS) system, which dramatically increases ground clearance in the center rear of the Big Bear. Both the front and rear suspensions on the Big Bear feature double wishbones with 5-way preload adjustments.
Left:New full floor boards offer excellent splash protection in sloppy conditions. Plenty of room for boots is provided below the pedals and extended foot pegs help you throw your weight around in those heavy rutted situations.Right:With the 4 wheel drive selected, you can slide a protective cover to the right and push the yellow button to lock the front differential. The button is covered to prevent accidental dif lock, which could make the next corner quite interesting.
Having tackled engine cooling, brake longevity and clearance issues, Yamaha next addressed one of the biggest issues with mud: traction. They attacked this challenge from several angles, including selectable 4WD, a locker and proper tires.
The Big Bear 400 performed remarkably well in two wheel drive, which is how I like to ride whenever possible. This allows for better maneuverability, steering response, and allows the rider to slide the rear end around a bit with the throttle cracked open. But when you need the 4WD, it’s right there at the push of a red button.
But what’s this? Another button, a yellow button? O sweet traction action — a dif lock at the touch of a button! Just like with our trucks and SUVs, ATV power can get lost on the wheel that’s least solidly on the ground. The solution here is a push button 3-way locking front differential. Nice!
A high-mounted air intake and marine-style connectors allow the Big Bear to plow through some serious water crossings.
But getting power to the wheels doesn’t always mean it gets all the way to where the rubber meets the road, er mud. Yamaha found that lots of ATV buyers who use their machines in the muck and mire buy aftermarket mud tires. Yamaha figured that any self-respecting built-for-mud machine should come with mud tires from the factory. Enter the ITP Mud Lites, which are the most popular aftermarket ATV tires in any category and are found stock on the Big Bear 400. An ATV buyer who purchases this machine for mud use will save hundreds in tire costs alone. ITP Mud Lites grip in mud and they clean out well to keep gripping in mud.
Other mud loving features include a high-mounted air intake, full floorboards and a redesigned seat for added rider maneuverability. The floorboards do an excellent job of keeping the rider relatively clean and dry in very wet and muddy riding conditions.
Left:The Duragrip-coated steel rear rack can carry 176 lbs. You can pack another 88 lbs. onto the front rack and tow loads of up to 904 lbs. via the center-mounted rear hitch. Right:The Big Bear 400’s all new independent rear suspension provides a significant increase in ground clearance for that high ridge found in the middle of well-used trails.
A five-speed, semi-automatic transmission allows the mud rider to manually select gears without operating a clutch. Shifting up with the left foot takes the transmission through all five forward gears. Shift down to gear down. One notch past neutral (all the way down) combined with a switch on the instrument panel puts the Big Bear in reverse.
We got a chance to test the new Big Bear 400 in the middle of mud machine country. The night before our ride the skies opened up and blessed the Dirty Dog ATV Park in Phoenix, AL with copious amounts of rain, making the 400 acres of trails a test of both mud and standing water. The Big Bear was definitely up to the task.
Like many utes, the made-for-mud features of the Big Bear are not the best formula for hi speed cornering, but if your off-road adventures include a lot of mud the Big Bear 400 4x4 IRS is your machine. Read more about ATV Tires
MSRP: $5,599.00