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The first ride on the 2007 Yamaha Big Bear 400 IRS 4x4

The first ride on the 2007 Yamaha Big Bear 400 IRS 4x4

2007 Yamaha Big Bear 400 IRS 4x4 ATV
Alabama - Out of the woods comes Yamaha’s latest ATV. The Big Bear series has taken yet another turn from its original facet and now pinpoints the enthusiast who wants to play in the deepest muck and mire. Yes the team over at Yamaha had quite a time trying to narrow down an ATV that was rider specific. The new Big Bear targets riders from the southern state of Texas all the way over to Georgia and those in between.

This region’s most popular ATV of choice is the Air-cooled 5 speed 4x4 market. It seems that the consumer likes to take a dependable four-wheel drive ATV and put it in the most adverse conditions. And this is where Yamaha’s Travis Hollins began preparing for the development of the new Big Bear 400. So off we go to Middle Eastern Alabama for some serious off road fun at the Dirty Dog Off Road Park. This place is known for its deep mud drags and serious swamp like conditions that will surely serve up some messy conditions. With a brand new machine and plenty of varying conditions we began looking at what would get us through the day.

The New Big Bear has a fully independent front and rear suspension setup. There is 10.5 inches of maximized ground clearance included free of charge with this Bear. The rear independent suspension puts the “snag” center up just a bit higher allowing the Big Bear to cross more obstacles without getting stuck on them. This will also allow the tires to dig for better traction. As with a solid axle the ride tends to be just a bit rough, but adding the IRS to the rear of the Big Bear it seems to soften it out and it makes the ride easier for those long days out on the trail. We found that the truth was evident on all these especially for the tires.

2007 Yamaha Big Bear 400 IRS 4x4 independent rear suspension
2007 Yamaha Big Bear 400 IRS 4x4 independent rear suspension
The Big Bear has always been at home in the mud, but with its new independent rear suspension boosting an impressive 10.5" of ground clearance along with the addition of fully-locking differential. The Big Bear can explore even deeper mud pits right off the showroom floor especially since it now also comes equipped with the popular ITP Mud Lite tires with an appetite for mud.

The tire of choice for the new Big Bear didn’t take very long as the only tire with a muddy rep in its background had to be the ITP Mudlite. It has become the best selling aftermarket mud tire in the industry and that’s another number one for Yamaha. Yamaha surprised the industry by taking an aftermarket product, which performs the best in its class, and placing it onto their new machine. The Big Bear comes straight from the dealer floor with the shoes it needs to get into some serious mud. Not only does the ITP Mudlite give up complete mud traction in the deep stuff but also it is lightweight in design and this will make your steering a lot easier. But this isn’t the only extremely attractive selling point that has been made in the Big Bear 400.

2007 Yamaha Big Bear 400 IRS 4x4 rear braking action
For long lasting and non-fading rear braking action, the Big Bear is now equipped with a sealed wet brake, which isn’t affected by harsh mud riding conditions.
The guys over in the Newnan Georgia plant wanted to make a statement about reliability and we think they have hit a home run. Developing an ATV for the mud is one thing but making it last is another. The rear brakes on the Big Bear 400 have been enclosed in the same casing that houses the rear gears. This not only seals them from outside elements it makes them last a lot longer. Yamaha claims to have the longest lasting rear brakes in its class because with 5 discs and in a reverse clutch style operation the rear brakes should last the life of the ATV in normal riding conditions. As we rode through the many miles of trails and hitting each muddy pond on our way I noticed the rear brakes were always dependable. I still felt the front slipping due to the amounts of water and mud they were placed in but I relaxed knowing I could count on the rear brakes at any time.

And then there was the newly redesigned 386cc four-stroke single cylinder power plant. The first thing I noticed about the Big Bears engine was its air-cooled design. The air-cooled engine is such a rider friendly feature and it helps eliminate problems with a clogged radiator and over heating not to mention the added weight reduction by removing the radiator and other components. This was good but how do you keep an air cooled engines oil stable while digging deep into mud which acts as a big coat for the motor and holding heat in? Well the designers didn’t let us down on that one either as they added 30% more cooling space to the oil cooler and moved it up and under the front fenders to help keep out the debris that might clog it up. Yamaha is serious about this mud monster.

2007 Yamaha Big Bear 400 IRS 4x4 386cc SOHC air cooled engine
2007 Yamaha Big Bear 400 IRS 4x4 air cooler
The proven 386cc SOHC air cooled engine remains at the heart of the Big Bear, but the oil cooler is 33% larger and moved higher in the chassis for improved engine cooling

The carburetion on this Big Bear is a standard Mikuni 33mm and leaves the general mechanic in control of maintenance by keeping it simple. Working on the Big Bear is a breeze and that’s what Yamahas intentions were. The team over at Yamaha wanted a user and mechanic friendly ATV. They also kept the ignition simple by using the standard DC-CDI type ignition.

Engine breaking has long been a subject in the 4x4 ATV arena and the Big Bear is no stranger to this. There is enough engine breaking to be helpful yet not overbearing, and I guess if it comes included in the low price point of the Big Bear it has to be just another great feature, which is yet another place where Yamaha has hit the bull’s-eye.

The transmission in the Big Bear is a 5-speed auto clutch design that includes a reverse gear. The Yamaha Big Bear has a limited slip and fully lockable shaft driven drive train, which is all-selectable, by the pressing of a button on the right side of the handlebars. This is where I seemed to have my only regrets with the Big Bear. First gear has become the pulling gear as it is low, low and there is really no other use for this, the primary gear for the Big Bear. Second gear is more like a real first gear and it seems that it would work better in that first position. The gearing is spread far apart from second to third but then remains consistent from there to 5th. Perhaps just a slight change in the transmission to equal out the variety of ratios would be better suited for the Big Bear. Depending on what gear we were in really gave us varying opinions of the engines performance. Overall the transmission changed through the gears easily and gave little trouble.

The plastics on the New Big Bear gave us maximum protection, and with the addition of the full floorboards, I felt even more confident that I wouldn’t need the extra goggles and socks I had brought along. The seating was even more plush this year as Yamaha added more cushion to the padded areas for improved comfort. The color choices vary from a Yamahas Steel blue to Red, Hunter Green and Hardwoods HD Camo. There are Dual Krypton 30 watt multireflector headlights and a super bright Tail Light.

2007 Yamaha Big Bear 400 IRS 4x4 dash
2007 Yamaha Big Bear 400 IRS 4x4 three-way on-command system
Nothing fancy about the dash, but it provides the basics with a Speedometer/odometer & fuel gauge along with the key and reverse engagement knob
Just like the Grizzly, the Bear Big features the three-way On-Command system featuring push-button 2WD/4WD and 4WD with differential lock

The speed-o is so simple and it only has an Odometer included with it. The fuel gauge is mounted into the tank and is nothing short of simplistic. This is a Mud riders machine and it should be easy enough for even the slightly mechanically inclined to care for. And should the battery get low in the winter months a tug on the pull start will get you on your way.

Our overall impression of the Big Bear for 2007 is this machine is right on task. Southern gentlemen everywhere will become mudbugs for life with just a few hours on this machine.

Yamaha Motors

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