In recent years a new engine category has developed in the sport-utility ATV market. The 450cc class is where features and cost are supposed to find their best balance. Suzuki has targeted this segment with their King Quad 450. The 450 is the "little brother" to the King Quad 700, with many of the same amenities but with a smaller engine and a lower price tag. When Suzuki developed the 450, they took the opportunity to re-design the chassis and suspension. In doing so, they improved upon an already very good design and in many ways they have raised the bar for this emerging class of ATVs.
Just the Facts
The King is powered by a 454cc, Single Overhead Cam, single cylinder, liquid-cooled 4-stroke fuel-injected engine. The engine turns a rubber v-belt CVT transmission that has an exclusive engine-braking design. The primary clutch has an integral clutch pack that allows the drive belt to be disengaged at idle. The secondary clutch in the CVT powers a low-high gearbox that in turn transmits power to the drive shafts. The King is equipped with independent suspension at all four corners and adjustable springs with five pre-load settings. There is a rear sway bar. Push-button four-wheel-drive capability is standard along with an easy to use locking differential switch. The 2008 450 King has the same 30 Watt, bumper-mounted headlights as the 700 King Quad, but does not have the 700's 40 Watt handlebar-mounted headlight. The engine starts with a push of the button on the left hand control. The engine will not start unless the ATV is in neutral, or in a forward gear with the front brake being applied.
Let's Take it to the Trails
One area that could have used some updating in past King Quad designs was the steering and handling. Suffice it to say, with the 450 Suzuki has made great progress and now ranks among the industry leaders in this category. The 450 is exceptionally well balanced and the suspension is forgiving and plush with seven inches and change of travel in the front and slightly more than eight inches of travel in the rear. On rough trails with frequent shifts in the terrain the King Quad inspires confidence with its excellent front-end geometry and well-calibrated suspension. The design keeps the rider's mass in the middle of the x (left to right) and y (front to back) planes and keeps the center of gravity low in the z (vertical) axis. What this means is that when a rider encounters sudden drop-outs, rises or unexpected jumps on the trail the King Quad stays in control. Spring settings were perfect right out of the crate. Steering feedback is minimal, which allows a rider to stay in the saddle longer without becoming tired and helps the ATV remain stable. The 450's power band feels strongest in the mid RPM range. Top speed is more than sufficient for trail riding and accessing hunting areas.
Ground clearance on any ATV with Independent Rear Suspension is a variable based upon how much the vehicle is squatting under load, but the Suzuki's is very competitive. The Dunlop 25" front and rear tires provide a good mix of performance for both trail and mud. In truth the tires could use deeper lugs, and the tires are one of the few things that could be upgraded, but overall the two-star rated meats work well. The seat height is optimal for a vehicle with this much ground clearance and seat comfort is good.
Coming Through in the Clutch
The King Quad 450 has both a centrifugal "starting" clutch and a Sprague bearing clutch integrated into the drive clutch on their CVT. The starting clutch is used to engage the drive train while throttle is being applied, the Sprague clutch is used to couple the drivetrain torque back into the engine and produce engine-braking when the rider is not pressing the throttle.
The centrifugal clutch does not engage the drive clutch to rotate until an acceptable RPM level is reached. This feature reduces belt and clutch wear because there is no friction between drive clutch and belt when the engine is idling.
The Sprague bearing clutch is a design that Suzuki based upon their starter motor clutches. This type of clutch goes by many different names throughout the industry including "one-way bearing clutch", "overrunning clutch", "Sprague clutch" and even "Sprag bearing clutch". This clutch is essentially a ball bearing design that does not have spherical rollers. Instead the rollers have an irregular hourglass shape. When the bearing is spun in one direction the rollers will cam out and float thus isolating the inner race from the outer race. When spun in the other direction though, the rollers cam in and wedge, coupling the inner and outer race. With Suzuki's engine-braking CVT, the drive clutch is coupled to the outer race and the crankshaft is coupled to the inner race. When the engine RPM is greater than the drive clutch RPM meaning the rider is on the throttle demanding power, the Sprag clutch is not engaged and the system instead relies upon the centrifugal clutch to transmit engine torque into the CVT.
When the rider lays off of the throttle the engine RPM plummets, and soon the drivetrain RPM being transmitted into the drive clutch exceeds the engine RPM. That means the outer race in the Sprague clutch is going faster than the inner race, reversing the roller direction and the rollers wedge into place. When this occurs, drivetrain torque is applied to the crankshaft and the engine turns into an air pump that cannot receive enough air so it begins to slow down. Another way to explain the effect is: When being driven normally the throttle opening is feeding the engine air (along with fuel), driving the engine to go faster. During engine braking the throttle is closed and actually becomes a restrictor. The engine is being turned externally by the drive train and is trying to draw more air in than the throttle will allow.
Performance on Hills
Suzuki developed a custom engine-braking system for their ATVs, and they obviously did their homework on it. The engagement of the engine-braking feature is seamless and noiseless. When beginning a 45-degree hill descent, having entered the slope at about 20 miles per hour, the engine braking brings the bike's freewheeling under control immediately without pitching the rider over the handlebars. This allows an aggressive rider to approach hill descents quickly, which is a refreshing feature compared to an ATV that must be brought to a standstill before descending a hill. If a rider applies an ATV's brakes when going downhill, they should apply only the rear brakes because locking up the front brakes can cause a flip-over. The KQ's rear brake is an advantage in this regard. The King's back end is equipped with an innovative maintenance-free fluid-shear brake that was an offshoot of their short-lived partnership with Kawasaki. Many riders who have experience with this unique and reliable type of rear brake hope that other brands will follow suit once patent restrictions expire.
When it comes to hill climbing capability, the King Quad has good acceleration, especially for it's engine size. The hill-climbing power should be sufficient for nearly any hunting application. Suzuki's focus on weight reduction, along with their experience in fuel injection design, really made a difference here. The fuel-injected 454cc engine will bring a rider up a steep hill at a very good pace without the engine laboring too hard. Credit the smooth operation of the engine under these circumstances to a well-tuned fuel injection system that is properly programmed to vary it's output per load. "Load" is defined as the difference between what the engine RPM is, and what it should be, based upon the position of the throttle position sensor. The semi-aggressive tread on the tires helps with uphill pulling, and if some serious climbing is required, the four-wheel-drive system will add extra traction. The low center of gravity also helps. Overall, the 450 conquers hill-climbing chores effectively.
Night Time Performance
Hunters often ride their quads before sunrise or after dark, so nighttime operation can be critical to us. The King Quad 450 harnesses the output from the 30-Watt dual-burner, bumper mounted headlights well. Low beam patterns provide good coverage in front of the ATV for good visibility on tight trails. The high beams are powerful, have a wide and tall pattern with little wasted light, and their pattern covers both nearby and well out in front to help in recognizing obstacles while they can still be dealt with by the rider. It would be nice to have some back-lighting on the controls for easier locating of the switches, but this should not be an issue once a rider is familiar with the location of each control.
The King Quad 450 has all of the features necessary to make it a premium hunting ATV but comes with a lower price tag than most premium rigs. One version of the KQ is available with Realtree's Advantage Max-4 camouflage pattern that hunters will like. I had an opportunity to use the King Quad while bear hunting. I was hunting at my own bait station in a Minnesota white cedar swamp. It is an understatement to say the terrain was rugged. I used the King to haul bait many times through unforgiving country. After whacking a 300 lb bruin the real work began. I wove the surprisingly strong King Quad again through the forest to the downed bear, which had dropped in it's tracks from my rifle shot through it's spine. I used a winch-powered lifting device to get the big bruin onto the front rack. The ride out was an adventure in itself as my ATV dipped and rolled over the terrain, however the King Quad proved itself to be a sturdy hunting partner. Despite being crushed into trees, stuck in the mud and other forms of abuse, everything held together-even the body plastic.
Other hunter-friendly features include: powder-coated steel tube racks providing space for tying down loads, fenders wide enough to provide good protection from mud spray, and a front grill area that has a lot of room for installing a winch. The push-button four-wheel-drive with a locking front differential is not a new design, but is still hard to beat for traction when the going gets tough. The King does not have a receiver hitch in back, but it does have a spot for a ball hitch that could be used for pulling a trailer.
The 2008 450 King Quad ranks very highly in the 450cc class. The handling is tight, the suspension plush, the engine is smooth and powerful, and it looks good too. Suzuki obviously did their homework with this model, and ATV enthusiasts will find it a pleasure to ride.
Gary Gustafson was formerly employed in the engineering departments of Polaris and Arctic Cat. An avid hunter and outdoorsman, he is now President of G-Force Consulting and lives with his wife and 5 kids in Northern Minnesota.