Kawasaki’s 2005 KFX400

photos by Cuck DeBault

Carburetor and cam updates have made the 05 KFX a freer revving and more powerful machine. The new Blazing orange added some extra flair to the KFX already mean styling.Early on in our sport and now in 2005, with the exception of a few models — sport quads have been divided into two distinct categories, sport and high performance. The once venerable 400EX has been slated by most riders as a sporty trail machine, while Yamaha’s YFZ and the newer Honda TRX 450R are considered to be more thoroughbred racers. Somewhere in the middle lies the KFX400. An exact replica of Suzuki’s Z400 this machine is also shared by Arctic Cat, although the Arctic Cat did not benefit from this year’s updates that grace the 2005 KFX and Z models.

Even if you haven’t been following the race scene very closely, you’re probably still aware that Doug Gust won the national motocross championship on this machine in 2004. OK it was actually a Suzuki, but like we said, the KFX is an exact replica. How is it possible that a 400cc class machine can beat the mighty new Honda and Yamaha race quads at the most competitive level? Is the KFX400 a hopped up sport machine, or a detuned racer? Could this be the ultimate do it all machine for the average rider? Read on as we give you the skinny on this orange machine from Team Green.

Not just for looks, the KFX piggyback reservoir shocks with adjustable compression and rebound damping have taken both the KFX and the 400cc class to the next level.	Heavy metal; while the KFX swingarm is constructed of aluminum in order to keep weight down, this beefy unit looks like it could survive a nuclear war. Chain adjustment is acceptably simple.

 

2005 updates
When this motor originally came out of the Suzuki DRZ400 dirt bike, it was detuned with a smaller carb, milder cam, and different CDI with a milder curve and lower rev limit. Perhaps they felt that the DRZ dirt bike motor had too much power for the chassis/suspension package on the ATV, or maybe they were just trying to make the machine more affordable. Either way, the 03/04 KFX motor had plenty of room to add horsepower and for 2005 they took advantage of it.

On the intake side, the KFX now features a 37mm CV style carburetor with a throttle positioning sensor, (TPS) designed to increase throttle response and increase top end power. A TPS works by adjusting the ignitions timing to match the throttle position. To allow the four valve double overhead cam motor to breathe deeper, higher lift intake and exhaust cams were installed. These changes are good indicators KFX is destined for more mid to top end power, but we will have to wait for some ride time to know for sure. Looking for better clutch operation and feel, one additional clutch plate was added bringing the number up from 8 to 9.

Going for more then just motor mods, the KFX front shocks are now equipped with piggyback reservoirs which feature adjustable compression and rebound damping. Wheel travel remains the same at 8.5 up front and 9.1 in the rear and the front shocks are now rebuildable and revalveable. To keep things all together, gussets were added to the upper front shock mounts and the subframe was strengthened a bit. This should help fix those premature frame issues what popped up early in the machines life.

Wanting to remain the lightest machine in the 400 class, Kawasaki’s KFX went through some weight shaving in order to offset the piggyback shocks and frame strengthening process. For the engine, on went a new magnesium valve cover, clutch cover and ignition cover. In the bolt on department, a new aluminum front bumper and aluminum rear grab bar replaced the old steel units. Finally for better shifting and even further weight savings, the steel shift lever was swapped out for a lighter stronger aluminum piece.

Pushing too hard on hard packed terrain can result in body roll and two wheeling due to the machines super sticky radial tires. Throw in some loose soil and powerslide to wheelee combos are a snap on the very nimble KFX.

 

Test time
While the high performance 450s are geared more toward all out cross country racing and occasional MX use, the 400cc class sport machines are geared more toward the aggressive trail rider. However, to assume that a skilled trail rider will never venture his or her way onto a motocross track would be foolish. For this test it’s the good old trail/ track combo platter and there is no better place to get started then in the environment for which the KFX400 was designed.

For the trail part of our test we loaded up our 05 KFX400, test riders Robby (BIG-G) Frede, and Nathan Delabar and headed for Big Rock ATV Park in Maysville, KY. Big Rock has plenty of tight trails as well as lots of wide open prairie trails, to test the Kawasaki’s low and high speed manners. After which, we took the machine to Earlywine’s Indoor Motocross to let Chris Earlywine put the KFX through its paces on his lipped up SX layout.

 

Rocks, boulders, and trees, oh my!

Having arrived at Big Rock ATV Park and with the arguments of who gets to ride first behind us, it was time to fire up the KFX for the first time. The machine can be started in any gear with the clutch pulled in. The choke is a snap to locate as it is conveniently located on the left side of the handlebars. After allowing the Kawie to warm for a few minutes, off went the choke, in came the clutch, Robby clicked the machine into first gear and off he went.

To get used to the machines power and handling characteristics, we started in some of the Parks more wide open sections. Both of our test riders were quick to note the machines quick revving yet extremely usable power delivery. Nathan, (our more experience test rider) was surprised at how large a difference the cam and carburetor updates made to the KFX’s overall power. Although the machine is not a torque monster, it carburets well at lower RPMs. A beginner can ride a gear high and lug if he or she wants, but the KFX does its best from one third throttle up. The overall power delivery is quite smooth, not 400EX smooth, but then again the KFX is notably faster. Overall, it’s a mid to top powercurve with a smooth midrange surge and enough top end to keep all but the most ham fisted trail riders happy. In the tight sections the free revving KFX was a blast to rocket between corners and climbing steep hills with little run was a breeze as long as you can keep the front end planted.

Suspension wise, the KFX is a joy on the trail. The suspension handles high speed acceleration and braking bumps with ease. On Big Rocks tight trail sections there are plenty of sharp edged rocky climbs and decants and plenty of exposed roots. While you can feel the obstacles you are rolling over the suspension never transferred any square edged hits to the handlebars. Heading out we managed to find a puddle jump that provided a few feet of air and we jumped it multiple times landing on both the front and back wheels. We never bottomed the machine, and no matter how we landed it the impact was supple and totally controllable. For trail use this may be the best suspended machine on the market.

Handling on the machine is mostly all good. Turning is quick and precise. At lower speeds you can rail through the trees without effort. Everything on the machine feels just right. However, as we begin to approach race speeds in the woods, or maneuver aggressive in wide open spaces, our test riders noticed a bit more body roll then they liked. While this might not offend the casual to intermediate level trail rider, you will have to get more radical with your body english as speeds increase. It was also sometimes difficult to get the rear end to break loose on dry hard pack. Switching to a lower profile set of rear tires will go a long way in solving both of these issues. A good weight balance with a wheelbase shorter then the 450 class machines seems to work well in most trail conditions. Lifting the front is as easy as leaning back and nailing the gas. This makes crossing ditches and fallen logs a snap. On the flipside, climbing extremely steep rough hills with little run is a bit tricky.

For slowing down or descending steep hills, the brakes are awesome. Steep decants are far less intimidating when you know you have this much braking power at your disposal. Feel is progressive making it possible to dial in just the right amount of braking power while you never have to death grip the levers to bring the machine to a halt. Good stopping power is also aided by the machines sticky Dunlop Radial tires, which do an excellent job of keeping their knobs planted firmly in the soil.

It doesn’t take long to get used to the seating position on the KFX. The ergonomics are spot on for various sized riders. While the machine fits riders 5 ½ feet tall just fine, Nathan Dalabar at 6’-5″ didn’t complain of being cramped. All of the controls work flawlessly. Throttle action is quite light and the clutch requires just a finger or two to pull it in. Vibration is not a problem on the KFX, making the machine even more comfortable on long rides.

Back to the track.
Next we took our KFX to the great indoors at Earlywine’s Indoor Motocross to put it through some moto punishment. While Robby and Nathan are both beginner level Motocross riders, Chris Earlywine, our Expert level MX tester was more then up to the challenge of seeing what the KFX had, on his tracks high banked peaked out course. One by one our test riders went out on the track and rode according to their ability level, here’s how it turned out. Chris has extensive experience modifying these machines, and he was eager to see how changed the machine was for 05.

The motor was more then a match for most of Earlywine’s obstacles. Chris jumped everything except a 65ft triple with an extremely short run. Like Nathan, Chris was surprised at how much more potent the machines power delivery became with the new updates. Although he felt the power was much faster then the 03/04, and much smoother then the 05 YFZ we tested there a few months ago, However, Chris was willing to jump the triple on the YFZ that he decided to forego on the KFX. Jumping everything else was a snap for Chris and he even made short work of the tracks 60ft tabletop.

The suspension department was a big surprise on the track. Hitting your marks, the suspension feels rock solid. All but the ugliest landings are absorbed without any hard bottoming. Robby dropped from 8ft in the air to a flat landing and was amazed at how well it was soaked up. Chris was doing every obstacle as though he was riding on aftermarket suspension. While we are in no way claiming that the stock shocks are as refined as aftermarket units, we are saying that you can definitely have fun with it at a motocross track. The only time we bottomed hard was when we had Nathan purposely come up short on a double just to see how it felt when the suspension went clunk, it wasn’t fun, but it was a lot better then it would have been on a 400EX, and perhaps as good as the 450s. Action on both ends is good, but it’s just a bit smoother up front. We would definitely call it balanced though, great shocks. Handling on the track is fun and predictable, although if you push it too hard you will be gently reminded that you are not on a 450 class machine. As we mentioned from our woods test, turning is quick and precise, however the machine is a bit tipsy when pushed too hard in the turns. We’re not really complaining, in fact the KFX is so good, you sometimes think you are on a mild 450 rather then a super strong 400. As we mentioned earlier, the brakes are excellent and nothing different turned up on the track.

Wide open spaces are traversed in surprisingly short time thanks to the quick revving double overhead cam water cooled four stroke engine. Your friends that own 400EXs will have to drop some serious dollars to outrun your stock KFX.	Ascending this meadow hillside, Robbie is grinning from ear to ear and why not? The KFX is one of the most fun to ride machines of all time.

 

The bottom line
While we feel we have never ridden the “perfect” machine, when it comes to finding a machine that will serve the majority of sport/trail riders the best, the Kawasaki KFX400 comes darn close. The power, suspension, and handling are very balanced.

 

There is no stand out weakness in the overall package that holds the machine back. While the machine is spot on for trail riding, it still has enough in the tank for some moto or dune excursions.

 

With the right mods you could win national championships and if you’re looking for a machine you can take to the trails next weekend and race your buddies for bragging rights, the KFX may be as close to perfect as you can get in 2005.

Kawasaki KFX 400 Specs

Engine
Type:	4 stroke liquid cooled
Engine:	Liquid-cooled, four-stroke, single cylinder with DOHC and four-valves
Displacement:	398cc
Carb:	Mikuni BSR37
Starting System:	Electric
Transmission:	Five-speed-plus-reverse manual, multi-plate wet clutch
Drive Train:	#520 O-ring
Lubrication:	Oil injection
Chassis
Dimensions:
Overall Length:	72.0 in
Overall Width:	45.9 in.
Suspension/Front:	Dual A-arms with coil-over-shock, adjustable preload/8.3 in.
Suspension/Rear:	Swingarm with preload-adjustable shock/9.1 in.
Brakes/Front:	Dual hydraulic disc
Brakes/ Rear:	Hydraulic disc
Tires:	Front: 22 x 7-10 radial Rear: 20 x 10-9 radial
Frame:	High-tensile tubular steel alloy
Foot Pegst:	Serrated steel
Wheelbase:	49.0 in.
Ground Clearance:	10.4 in.
Fuel Capacity:	2.6 gal.
Dry Weight:	373 lbs.
Other
Lighting:	Dual 30W halogen
Colors:	Blazing Orange, Kawasaki Lime Green
Warranty:	1 Year Limited Factory Warranty
MSRP:	$5899.00

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