Kawasaki Brute Force 650i Evaluation

By Lance Schwartz
photos: Tom Simpson and Ron Henry
video: Ron Henry
test rider: Lance Schwartz

A Muscle Quad for the Masses
If you haven’t noticed ATV Scene has taken a specific interest in providing enthusiasts with information and product evaluations about the exciting market of big-bore, four wheel drive quads. Recent additions to the 4×4 quad wars have made these the most technologically advanced and exhilarating machines ever built. As a member of Team TPC PowerCenter, I had the opportunity to pilot a 2005 Kawasaki Brute Force 750i to the runner-up position of the 2005 12 Hours of ATV America. Having gotten intimately familiar with its strengths and weaknesses, I was very excited to hear the news that Kawasaki would be releasing a new 2006 Brute Force 650i. This machine was rumored to have some important mechanical changes to deal with some of the issues the 750i had. Whether those rumors were true or not, we knew the 650i would be one of those machines that we just had to throw a leg over.

Growing up as a child in the 1970’s, I remember my Dad taking me for rides in his 1970 Chevrolet Nova SS. As a little kid, I could recite to my dad’s buddies, on cue, that it had a 350 cubic inch engine with 300 horsepower. Even though I wasn’t old enough to ride a bicycle or understand the physics of horsepower, I knew that when my dad dropped the hammer on that old Nova SS, the 300 horsepower and the physics responsible for sticking me to the back of the seat put a huge smile on the face of both my dad and I. From my very first ride on the 2006 Brute Force 650i, the raw power and ferocious scream from the melodious V-Twin put that same smile on my face that I had 30 years ago. Everyone who has ridden this thing agrees that this quad is just plain, good old fashioned FUN! I think Kawasaki is responsible for creating their own niche market, and as such, have created a line of machines that will go down in history as the legendary “Muscle Quads”.

Baby got back IRS!

The Monster’s Heart
Our friends at Kawasaki are responsible for producing the most famous engine to ever make it to a big bore ATV. The engine has been produced in 650cc, 700cc, and 750cc flavors and these engines have been shoehorned into machines manufactured by Kawasaki, Suzuki, and Arctic Cat over the past few years. This particular version of their liquid cooled, 90-degree, four stroke V-twin power plant has a 633cc displacement, very similar to the original Prairie 650 engine. The engine features a bore and stroke of 80mm x 63mm, a compression ration of 9.9:1, and liner-less aluminum cylinders based on the units used by its 750i big brother. Also new in this engine is an all-new lightweight crankshaft which helps contribute to this machine’s awesome riding experience.

We’ve drag raced this Brute Force 650i against every utility quad we could find. This thing will run circles around almost any 4×4 produced. I recently had a chance to drag race the 650i against our 750i 12 Hour racer. Even though the 650i was down in engine size, it smoked our 750i repeatedly. The engine package, in addition to holes being cast into the transmission gears have made for a machine that accelerates like a rocket ship. Wheelies, burnouts, mud runs, power slides, and heavy duty chores are all feats that are easily accomplished with this big bad Brute!

You might not even see this much sick air at your local MX track. 

Suspension
Some of the best improvements over the bigger brother 750i come by way of suspension changes. Although the machines look nearly exactly the same, there are certainly some changes that separate this from its relatives. For starters, the 650i sits about 1 inch lower than the 750i. That doesn’t sound like much. However, it’s immediately noticeable when you want to carve corners with it. After spending countless hours on a 750i competing at the 12 Hours of ATV America, I know that the 750i’s biggest problem was steering. The 750i didn’t like to turn. After an hour, the turning issue is noticeable. After 12 hours, the turning problem is downright painful. I’m happy to report that the 2006 Brute Force 650i turns much easier than its big brother. This much needed improvement is a result of caster changes being made to both the upper and lower front A-arms. This change equates to lighter and more responsive steering. When pushed hard, the 650i resists a bit by providing some feedback through the bars. But, the steering is 100% better on the 650i than the 750i. The spring rates on the front and rear shocks have also been revised to improve ride comfort. The Brute Force gives a nice comfortable ride at any speed. The front shocks will bottom if you jump it too high. But, most of you aren’t going to take this thing to Rausch Creek Motorsports Park and run it on the MX track with a winch hanging off the front. We did! That’s when the front shocks resisted by bottoming out on some of the more extreme G-outs. It is immediately apparent that the 650i handles better in so many ways than the old 750i. The difference is truly amazing and I encourage you to try one out for yourself.

Brakes
The Brute Force 650i should be, from here forward, the litmus test to compare all big bore utility quad front disk brakes. If you can do repeated “stoppies” on a 600lb, four-wheel drive machine, you’ve got excellent brakes. The dual 200mm front disks made it possible for the Brute Force 650i to do “stoppies” at will and without reservation. If there was an optional windshield, the front brakes could put you through it if you grab a handful of lever too aggressively. Out back, Kawasaki’s enclosed wet multi-plate rear brake system carries over from the 750i. This system has worked well in many different applications and it returns similar results in the 650i.

Although these wet brake systems are durable, they don’t give the rider the pedal feel that a fully hydraulic system offers. I have a horrible habit of riding the rear brake system when I ride aggressively. To date, I’ve never managed to overheat this rear brake setup on this Brute Force or any other Brute Force. This is a testimony to its ingenious design.

Transmission
The Brute Force 650i transfers power from its venomous V-twin engine to the wheels through a dual range continuously variable transmission (CVT) featuring high, low, and reverse. We’ve loaded this machine down with weight on the racks, towed trailers with it, and even used it as a tow truck at a local AMA District 6 Harescramble event. In low range, you could crawl this thing up the side of a building! Another nice feature on this machine is the rider’s ability to select 2 or 4 wheel drive with the simple flick of a button. On the downside, on Kawasaki’s system, you need to be moving in order to engage the 4×4. So, if you anticipate the possibility of getting stuck, lock it in four wheel drive. If you happen to get stuck in two wheel drive, you need to be able to move the machine forward or backward a tad bit to get it to lock into 4×4 mode. Kawasaki carries over its variable differential lock system from the Prairie and bigger Brute Force. I personally think this system is superior to any locking differential on the market. Another thing worth mentioning is the very aggressive engine brake on this big machine. I can honestly see a trail rider being able to navigate without needing to use the brakes much at all. There are times when the engine brake seems overly aggressive. But, as you get used to it, the engine braking becomes second nature. I believe this to be the main reason I don’t have a problem overheating the rear brakes on the Brute Force.

Ergonomics
This thing looks monster truck tough. I absolutely love the new front bumper on the 650i. It’s just a bit different from the bumper used on its big brother, but it looks so much more aggressive. The material in the seat is said to have softer urethane foam than the bigger 750i as well. I spent countless hours on the machine and the seat and seating position are really comfortable. The Brute Force is tall and it feels the part when trying to negotiate tight woods with low hanging branches! My 6’2” frame in combination with the tall seat height of the towering Brute Force gave me a quick lesson on the intimate differences between the selections of trees that methodically kept whacking me in the head. I really love the way the Brute Force plastic is designed, because it looks fast even when it’s sitting still. The plastic shape is very aggressive and does a very nice job of keeping the mud off the rider. I do have a few complaints about the plastic though. We managed to break both plastic floorboards much too easily. Ironically, they both broke at two different times when I was riding in the jagged Pennsylvania rocks near my home, both on very cold February days. It seems like the cold made the plastic extra brittle and an innocent contact with a rock was all it took to crack each of them. One other suggestion might be a little wider handle bars. Since I have the build of Cosmo Kramer, my arms felt a little long for the narrow bars at times. Quite honestly, it was the biggest complaint of the large group of riders and racers that took it for a spin. They are by no means a reason to overlook a Brute Force 650i, however. I few phone calls are all it takes to get a replacement set to widen the bars to your liking.

The Brute Force borrows its well-designed and sharp gauges from the Prairie.

Riding the Beast
With a turn of the switch, a twist of the choke actuator, and a push of the green electric start button, this behemoth comes to life with a sound that is music to the ears. The Kawasaki V-Twins have always been known to be a bit cold blooded. So, a cough or a sputter on a cold morning was not uncommon. The new 650i does need the choke when cold-starting, but it doesn’t seem nearly as prone to hiccup as its earlier predecessors. After a few minutes of warm-up idling, the machine is ready to make the rider drool like Pavlov’s dogs, shoot rooster tails, and mow down anything in its path.

During the many dead start launches I’ve performed for this article, I became aware of something very interesting. It seems like the massive V Twin has the ignition retarded until it hits a certain RPM. From there on, it’s explosive acceleration. My guess is the engineers did this so this big fella doesn’t end up on the chest of an inexperienced rider with an itchy trigger finger. This sensation is much more evident in high traction areas where you can’t get the tires to spin and build rpm’s immediately. I noticed it on full throttle launches on high traction asphalt up to about 6-8 miles per hour. After that point, the Brute Force points its front end at the clouds and keeps it there as long as you have the throttle pinned.

I was able to do something on the Brute Force 650i that I’ve never done on any utility ATV before. I was able to do smoky muscle car burnouts with this 650i on the asphalt time and time again. I could have literally kept in the throttle until the Brute devoured its stock tires and was left spinning on its 12 inch aluminum wheels. I’ve never ridden a stock 650cc utility quad with this much power and it clarifies how the Brute Force got its name. In the dirt in 2 wheel drive, the Brute Force rips and tears at the ground beneath the tires with reckless abandon. The magnitude of horsepower in this engine makes power sliding it a breeze as well. The machine is tall, so keep in mind that you have to take extra caution and use some body English when sliding it aggressively, though.

The caster changes are a welcome addition to the 650i. We carved turns in pro race speed, (well not quite – but we had just as much fun). Under most circumstances, the stock wheels and tires work just fine. They provide adequate grip and their puncture resistance was excellent. As you can see from the pictures, we ride our utility quads like sport quads. When pushed, the limits of the narrow wheels and soft stock tires become evident very quickly. The tires will roll over almost to the rim of the wheel when you get it sideways at high speeds. That tendency along with the conservatively backspaced wheels makes it a little scary to ride fast. I nearly went over the bars on one occasion and our photographer was able to catch it on film as evidence. Our solution was to bolt on a set of aftermarket wheels and tires. We used a set of Douglas Rokstars and tried both Maxxis Bighorns and Greenball Corporation (GBC) Dirt Tamers. With the aftermarket wheels and tires on, it completely transformed the way this Brute Force 650i handled. Most of the instability went away. There were also no more problems with the tires rolling over, since each of these similar designed tires are both 6 ply units. The difference this package made in the handling department cannot be explained in words. The heavier tire/wheel combo usually affects the power on lesser machines because the engine has to deal with the heavier weight that the aftermarket pieces add. Even with the addition of the wheel/tire combo and a 2500lb Warm winch hanging off the nose, there was nearly no noticeable loss of power.

Jumping this 600 pound machine was loads of fun. We took it down to Rausch Creek Motorsports Park and ran some laps with the guys on the sport bikes. This big Kawi flew through the air really well. Landings were soaked up nicely, in part, to the adjustable spring preload on the shocks. The Brute Force has a tendency to push when you’re hard on the gas, but it worked well enough in an environment it was never designed for.

Can less be more?

The point that I was most satisfied about was that Kawasaki listened to the complaints about the noticeably large amount of effort needed to steer the original Brute Force 750i. With the redesigned front suspension geometry, the 650i steers much better than its big brother. In fact, it leaves me wondering why anyone would buy the more expensive $7599 Brute Force 750i over the $7099 650i. If it was my money, I’d buy the 650i and buy aftermarket wheels and tires with the $500 I just saved. The guys that love their 750i’s would likely love a 650i with aftermarket wheels and tires even better than their 750i! This leads me to believe that Kawasaki might have future plans for the 750i. Why build a 650i that can spank a 750i in nearly every aspect for a lot less clams? I guess we’ll have to wait and see if there is more in store for the 750i in the future. If so, I’d like to reserve my test unit today Kawasaki!

Carving sharp corners at speed requires a lot of rider input on this tall machine.

The comfortable ride and large fuel capacity of the Brute Force allows you to ride for hours.

Crawling, Towing, Hauling and Plowing
We did some hard core hill climbing and rock crawling with our mighty Brute Force. In doing this, it is easy to see that this Kawi might be the best rock crawler on the market at this price point. The high ground clearance combined with the independent suspension made negotiating obstacles a blast. Even with one or two tires clawing at nothing more than air, the machine was able to maintain forward momentum in search of the next challenge. The Brute Force 650i has enough power to climb any mountain. But, the climbing must be done with cautious usage of the thumb throttle. The Brute Force has so much power that even with conservative use of the throttle, the front end often ends up in the air. Going down hills can literally be done without touching the brakes. The engine brake monitors speed and adjusts itself to allow for smooth, drama free descents.

Finally, we did some testing on the 2006 Brute Force 650i that incorporated activities that most of these quads would encounter often during their lifetime. We pulled big heavy trailers, towed broken quads out of the woods and back to safety, plowed snow on cold wintry days, and used the Brute Forces racks to double as a pack horse on trail rides. All of these tasks are done with ease and confidence. It is easy to see that the engineers had activities like this in mind when they were designing this machine because it looks and performs the part. You’ve probably heard the phrase, “If it walks like a duck and quacks like a duck, it must be a duck”. Well, in our test machine’s case, “If it growls like a brute and hauls ass like a brute, it must be a Kawasaki Brute Force 650i”!

A look at the carnage of the Brute Force’s weak plastic floorboard.

The limits of the stock tires become evident when riding aggressively. Here the rider nearly goes OTB as the front tire sidewall rolls clear to the bead of the rim.

 

Saying Goodbye to a Friend
Unfortunately, today is the day we have to return our 2006 Brute Force 650i to our friends at TPC PowerCenter in Bloomsburg, PA. They will be responsible for servicing it and preparing our green machine to go to Field and Stream to serve as a test mule for their editors. I was very excited to try this machine out. After riding it for the past few weeks, I’m even more excited to deliver the good news for those enthusiasts in the market for a big bore four wheel drive utility quad. I am a huge fan of the 2006 Kawasaki Brute Force 650i. For the price, I don’t think there is a machine with a bigger fun factor than this monster.

When I’m old and gray, I imagine myself reflecting on the quads that left a lasting impression on me, just like the muscle cars of the 70’s have done with so many motor heads in the past. I am positive that this machine will be on my list of long time favorites simply because it is so much fun to ride. I also think when the 2006 Brute Force 650i comes up in conversations about what I did “back in the day”, this mighty Muscle Quad will be responsible for producing the same smile on my face that my dad’s old Nova SS did back in its day.

Specs:
Wider wheels and stiffer tires make the Brute Force 650i handle much better than stock.Engine: Liquid-cooled, 90-degree, 4-stroke V-twin
Valve system: SOHC, four valves
Displacement: 633cc
Starting system: Electric with recoil back up
Bore x stroke: 80 x 63mm
Compression ratio: 9.9:1
Carburetion: (2) Keihin CVKR-D32
Ignition: DC-CDI
Transmission: Dual-range CVT plus reverse with Kawasaki Engine Brake Control
Final drive: 2×4 / 4×4 shaft
Frame: Double cradle, tubular steel
Front suspension / wheel travel: MacPherson / 6.7 in.
Rear suspension / wheel travel: Aluminum swingarm and single shock / 7.2 in.
Front tires: AT25x8-12
Rear tires: AT25x10-12
Front brakes: (2) Dual-piston disc
Rear brake: Sealed, oil-bathed, multi-disc
Overall length: 86.0 in.
Overall width: 47.7 in.
Wheelbase: 50.9 in.
Ground clearance: At center of chassis, 9.0 / at rear axle, 7.3 in.
Seat height: 33.9 in.
Lighting, headlights: (2) 45-watt headlights, taillight, brake light
Total rack capacity: 264 lbs.
Towing capacity: 1,250 lbs.
Dry weight: 602 lbs.
Fuel capacity: 4.8 gal.
Instruments: Speedometer, odometer, dual trip meters, clock, hour meter, fuel gauge, 2×4 / 4×4 indicator light, neutral indicator light, reverse indicator light, low fuel warning light, low oil warning light
Colors: Woodsman Green, Aztec Red

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