Suzuki raises the bar with this sport utility machine
In recent years, a new engine class 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 its King Quad 450—the ‘little brother’ to the King Quad 700, with many of the same amenities but a smaller engine and a lower price tag. When Suzuki developed the 450, the company took the opportunity to redesign the chassis and suspension. In doing so, it improved upon an already very good design and raised the bar for this class.
Just the facts
The King is powered by a 454cc, single overhead cam, single cylinder, liquid-cooled 4-stroke fuel-injected engine, which turns a rubber v-belt CVT transmission that has an exclusive engine-braking design. 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 2007 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, and will not start unless the ATV is in neutral or in a forward gear with the front brake being applied. The 450 is equipped with an LCD display in a size that seems to have become a standard for most Japanese ATV manufacturers.
The King Quad 450 has both a centrifugal ‘starting’ clutch and a Sprague bearing clutch integrated into the drive clutch on the CVT. The starting clutch is used to engage the drive train while throttle is being applied, and 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 its 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. This 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.
One area that could have used some updating in past KingQuad designs was the steering and handling. Suffice it to say, the KingQuad 450 now takes a back seat to no one 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 KingQuad 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. This means when a rider encounters sudden dropouts, rises or unexpected jumps on the trail the KingQuad stays in control. Spring settings were perfect right out of the crate. Steering feedback is not bad, 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, while not in the white-knuckle category, is more than sufficient for most trail riding or hunting applications.
True ground clearance on any ATV with independent rear suspension is a variable, based upon how much the vehicle is squatting under load, but at a rated 10.2 inches the Suzuki’s is very competitive. The Dunlop 25-inch front and rear tires provide a good mix of performance for both trail and mud. The two-star rated meats fit both needs well, but tires are probably the area most in need of an aftermarket upgrade. The seat height is optimal for a vehicle with this much ground clearance and seat comfort is very good.
Engaging the engine-braking feature is seamless and it is acceptably quiet in operation. When beginning a 60-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. The KQ’s rear brake is an advantage in this regard. The King’s rear differential is equipped with an innovative maintenance-free fluid-shear brake that was an offshoot of Suzuki’s 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 very good acceleration, especially for its engine size. The hill-climbing power should be sufficient for nearly any application. Suzuki’s focus on weight reduction, along with its 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 its 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. 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 very well.
Safe nighttime operation can be critical for many riders, such as hunters, for example. ATV headlights are, of necessity, a different animal than on-highway forward lighting systems. Low beam patterns should distribute an even amount of light on the ground throughout their coverage without hot or dim spots. High beam patterns should put out enough light far in advance of the rider so that the rider cannot out drive his headlights, and additionally enough light should be directed above the horizon to at least partially illuminate any hills that the rider may be about to ascend.
Proper light patterns are not a matter of chance. Light must be directed per industry regulations to be certified for sale. What harnesses and directs the light put out by the halogen bulbs is the headlamp’s optics. When lens optics are utilized, the polycarbonate lens is jeweled and the prisms are all optimized to direct the light to a certain area. The lens on a reflector-optics design will have an opaque appearance to it when not lit. Reflector optics have a jeweled reflector and a transparent lens. The reflector is the metalized polycarbonate backing of the headlamp assembly. Most reflector optic lamps have very obvious facets tooled into the reflector, and each facet has its own responsibility for a given area being illuminated forward of the vehicle. In a few cases, micro-reflector optics can be utilized that give the reflector a ‘smooth’ look, or even incorporate a logo or other design. The KingQuad 450 utilizes standard reflector optics, and they have achieved good light output for such a slim, stylish design.
The KingQuad 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 identifying nearby trail hazards. The high beams are powerful, have a wide and tall pattern with little wasted light, and they project both nearby and well out in front to help in recognizing obstacles while they can still be dealt with by the rider. The only drawback for nighttime operation is that the controls have no backlighting whatsoever, but this should not be an issue once a rider is familiar with the location of each control.
The KingQuad 450 has all of the features necessary to make it a premium ATV for such activities as hunting, but it comes at a lower price than other similar rigs. One version of the KQ is available with Realtree’s Advantage Max-4 HDT camouflage. In addition to the cool looks, camouflaged cabs do not show scratches nearly as easily as monochrome cabs. Powder-coated steel tube racks provide space for tying down loads, the fenders are wide enough to provide good protection from mud spray, and the front grill area has a lot of room for installing a winch. The push-button four-wheel-drive with a locking front differential is nothing new, but is still hard to bear 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 450 KingQuad ranks very highly in the 450cc sport-utility class. The handling is tight, the suspension plush, the engine is smooth and powerful, and it’s easy on the eyes too. Suzuki obviously did its homework with this model, and mid-bore ATV enthusiasts will find it a pleasure to ride.