Introducing the Kawasaki KFX450R

By Aaron Meyer
photos: Kenny Jones and Brad Phillips
video: Brad Phillips
test riders: Aaron Meyer and Brad Phillips

 I was recently honored with the opportunity to be one of very few people to swing a leg over the 2008 Kawasaki KFX450R masterpiece. It came when ATV Scene decided to send myself (Aaron Meyer of Team Cernic’s/ Answer/ Suzuki/ Kellogg’s/ Media Allstars) and Brad Phillips (of Premis Industries, makers of the popular Carpe Diem video series) to Kawasaki’s KFX intro at the luxurious Carolina Adventure World in Columbia, SC.

Before I got to ride the new green machine Kawie sat all the media in attendance down and provided an interesting overview which was presented by their top engineers and marketing executives.

Kawasaki really slammed into the new wave of the high performance ATVs. The new KFX 450R uses as much modern day technology as I’ve ever seen in an ATV. For starters it’s equipped with a 32 bit ECU fuel injection system that features a mighty 42mm throttle bore with an elaborate 42.6 psi fuel pump. Kawie’s pretty serious about getting fuel pumped into their impressive 450R engine.

 

.Engine
The KFX450R ATV uses a powerplant based on Kawasaki’s highly acclaimed KX450F motocross engine. The bad-to-the-bone 450R engine boasts 43 hp and 31.1 foot pounds of torque. The cylinder is made of a chrome composite plated material. The forged piston has a low friction coating and a larger diameter wrist pin for increased durability. Dual overhead cams keep the titanium valves moving.

Kawasaki paid close attention to making sure they kept the weight down on their made-for-the-track KFX450r and opted for a titanium head pipe for the Green Machine. Speaking of made-for-the-track, a special hop up kit is available from Kawasaki which includes a programmable ECU, a signal converter, a USB cable, a high performance silencer, a kick start and a new step guard. Kawasaki says this kit makes more power and eliminates some weight on the already light KFX 450R.

 

Chassis
Now here’s something that really got my attention and I think it will do the same for you. The KFX 450R features an all-aluminum chassis that weighs only 26 pounds! The subframe and swing arm are also aluminum. Are you starting to get the picture here? Less weight is where it’s at! By using all this aluminum, not only is the quad easier to maneuver, it’s also highly ridged. A ridged chassis can also offer gains in the performance of the machine. The conventional mild steel chassis tends to flex under power and stress, which can sometimes make for an unpredictable ride. The rigidity that the aluminum chassis offers eliminates chassis flex — making for a more controlable ride.

The front of the chassis is taken directly from race proven aftermarket systems and is actually similar in design to the old tried and true 250R Roll Design narrow front end. This narrow design helps reduce bump steer by allowing the use of longer A-arms. In addition Kawasaki mounted the A-arms closer together to help the KFX450’s handling characteristics even further.

In the rear, the aluminum swing arm is a cast unit that features increased thickness in high stress areas. Kawasaki says this will reduce swingarm fatigue and make it less prone to cracking.

The KFX450R’s chain adjustment is made easy with a conventional round-style bearing carrier. The UNI-TRAK linkage design is used on the KFX 450R’s linkage system which is similar to something you might see on Walsh Racecraft’s “Savior” linkage or a Yamaha YFZ 450 linkage. The knuckle linkage allows for the KFX450R to use a vertical shock — making for a great rear end combination.

 

Ride Time
I’ve been doing a lot of riding lately and feel I’m in great shape and really rolling well. So I couldn’t wait to put in a hardcore moto on the new Green Machine. I was there to punished it! I figured in order to get a good verdict on the machine you should ride it at race pace, right? Especially since the KFX features a not-so-common aluminum frame, I was anxious to see how well it would hold up to a few long hard motos of abuse.

Right away I could tell the motor had a nice strong pull from mid to the top end even on the big hills on the motocross track. The gearing felt spot on in the tight trails and on the track. I was able to get pretty comfortable on the KFX450R very quickly and started launching it off all the big jumps. I could really notice how light and nimble it was while in the air. And while carving turns on the ground I could quickly maneuver the machine with ease. It handled quite well to put it simple.

Kawasaki worked hard to keep the center of gravity low and I could definitely tell, but I think the seat is still little too high. And while I’m nit picking, I have to say that I did feel a little cramped while going through the corners, also the same cramping occured while I was trying to get over the back of the machine. The fenders were a little too close for me.

The KFX450R is the only machine in its class to offer a reverse gear. The lightweight reverse system might be a nice feature if you find yourself in a first turn tangle up or stuck in the mud at a cross country race.

The KFX450R is one sharp looking machine. The headlight assembly, as well as the front fenders, are quickly detachable. The two-piece front and rear “lapped” fenders make it possible to replace sections separately if they get damaged or if you just want to go without them. We especially liked this feature since the fenders did get in our way during hard rides.

 My Verdict
I feel like this machine in stock form will be good for trail riding and cross country racing, however it will definitely need some A-arms, an axle and Kawasaki’s race kit to make it competitive at the local motocross race scene. For you A and Pro-Am racers out there I think you will still need a good long travel front end and some good aftermarket shocks. Add a kill switch and some nerf bars and you’re good to go.

Punishing the KFX
Brad Phillips and I took it through mud, rocks, hills, water, motocross tracks – basically everything the place had to offer, which was a lot. We even crashed it!

 

After all the punishment Brad and I dished out the KFX 450R was still together and running when we walked away from it. In other words if you’re wondering how that aluminum frame held up, we couldn’t find any signs of wear and we looked very close.

Shortly after this fun-filled wheelie, Aaron dropped the hammer and put in a long hard moto. The bbig picture above sums it up well, as you can see he was all smiles about Kawasaki’s 2008 KFX450R.

 

Summing it Up
I was impressed. Kawasaki sure did take their time in getting into the 450 sport performance market, but boy did they just show up! After hours of hard riding on this machine, I don’t think it will be long before you start to see a lot of green at both cross country and motorcross tracks throughout the country. And with William Yokley, Jason Luburgh and Josh Creamer racing the new KFX this season in the pro ranks, a KFX pro victory might be just around the corner as well.

 

2008 Kawasaki KFX450R Features
449cc Liquid-cooled, four-stroke single, DOHC, four valves per cylinder 
– Based on the engine from the World Championship winning KX™450F
– A lightweight forged piston reduces reciprocating weight
– Triple piston rings and a 21mm diameter piston pin help increase durability and reduce necessary maintenance
– The intake ports feature a special coating. The extremely smooth surfaces improve intake efficiency at all rpm
– Lightweight titanium valves and aluminum valve spring retainers reduce reciprocating weight and boost high-rpm reliability
– Lightweight high-performance titanium exhaust header contributes to low and mid-range throttle response
– Electric starting facilitates quicker stall recovery and lowers rider fatigue
– Large-volume airbox contributes to both intake efficiency and the sharp engine response. An air duct fashioned from polyethylene (known for its ability to resist deformation caused by intake pulses) helps ensure stable engine performance
– Torque delivery is tuned to match the rear tires’ ability to deliver traction, making it easier to accelerate without excessive wheelspin. Efforts were made to achieve the widest possible torque curve, so that traction can be maximised through a greater part of the rev range
– Asymmetrical high-acceleration cams yield high intake efficiency

Digital Fuel Injection
– 32-bit digital fuel injection system uses a 42mm throttle body. This system measures coolant temperature, air intake temperature, air intake pressure, engine speed and throttle position, then automatically delivers the ideal amount of fuel to optimize power delivery
– Crisp engine response is especially advantageous for instant acceleration after landing jumps
– Fuel injection also provides trouble-free starting – a great benefit in races where riders line up with their engines off and need to start their engines before being able to blast away from the starting line
– Fuel injection allows the use of a lighter throttle return spring. This helps reduce rider fatigue, because less pressure is required at the throttle lever

Transmission
– The five-speed (one-down, four-up) manual transmission locates the reverse gear below first. Actuating the reverse-lock release lever when in first gear allows you to shift “down” into reverse
– Compact reverse-lock release lever can be activated with the right thumb, allowing the reverse gear to be engaged while still keeping the front brake lever depressed
– The combined weight of the reverse gear system and the lightweight aluminum chassis is no heavier than using a steel frame without reverse

Aluminum Chassis
– Highly rigid aluminum frame contributes to the KFX’s excellent handling and traction. The frame’s high torsional rigidity enhances stability in corners and allows the suspension to be easily set up to suit course conditions
– Designed for high corner speeds, the KFX ATV sits low to the ground, helping to reduce roll tendencies
– Mounting the battery and coolant tank in front of the engine lowers the center of gravity, and helps weight the front wheels for increased traction when cornering
– Single box-tube lower frame contains the front A-arm attachment points. This design is narrower than the competition’s frames and enables the use of longer lower A-arms

Advanced Suspension Design
– Positive and negative suspension travel enhances the front wheels’ ability to stay in constant contact with the ground. This helps maintain traction and steering authority during hard acceleration and in situations where the ground drops away
– Dual-rate front springs help deliver progressive suspension travel to provide excellent rough-surface handling
– Extra-long lower front A-arms help minimize camber variations through the suspension stroke, to maximize front wheel traction and boost stability
– Motocross style rear shock features both high and low-speed compression adjustability as well as adjustable rebound damping
– Cast aluminum rear swingarm features curved lines and rounded edges to help disperse stress, as well as different wall thickness for each surface, resulting in a design that is both light and strong
– The swingarm’s high torsional rigidity contributes to excellent rear wheel traction
– The rear axle is tapered for reduced unsprung weight

Front and Rear Disc Brakes
– Dual front hydraulic disc brakes offer consistently strong stopping performance
– Petal-type rear brake rotor reduces unsprung weight and helps clean the brake pads for more efficient braking performance in difficult conditions
– Integrated rear parking brake is designed to be easily engaged and released while wearing gloves. When engaged, the parking brake lever also prevents the clutch lever from being actuated

Additional Features
– Two-tone seat features a smooth top surface for excellent rider mobility and slip-resistant sides for good grip when hanging off in corners
– Seat, tank and side covers are shaped to allow excellent rider mobility and to provide support when hanging off in corners.
– Tapered Renthal Fatbar offers both strength and light weight
– Handlebar mount designed to accommodate other MX-type handlebars, enabling riders to select from numerous after-market styles
– Specially designed rear wheels feature reinforcing plates for the rims. Located on the axle side of the rims, these plates reinforce the rims where strength is most needed while minimizing weight
– Wide front bumper, can be gripped with two hands to push/pull the ATV
– Two-piece “lapped” front and rear fenders can be replaced separately in the event they are damaged
– Detachable front headlight assembly can easily be removed to reduce weight when racing
– Optional kick-start system is available for MX-style (GNC) races where light weight is a priority

 

Brad told us it was hard to not ride the new KFX. “It’s a really fun quad to ride. In fact of all the stock quads that I’ve ever rode, this one tops them all,” says Brad. Thankfully Brad succeeded in not riding for a while and got some killer video. Check it out – the link is at the top and bottom of this page.

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