Unlimited potential. Those are a pair of words you tend to hear a lot in football columns, usually to describe some athlete who's as likely to be the Next Big Thing (Michael Vick) as the Next Big Bust (Ryan Leaf). In the case of this magazine and this comparison, these two words were what made an unlikely rider alliance between the really fast and the slowest, who came together with one pick for the best ATV: the Kawazuki. OK, technically two picks, the KFX400 and QuadSport Z400--but both machines came off the same assembly line in Hamamatsu, Japan.
This unanimity in opinions came about because in its stock incarnation, the Z/KFX was a solid machine yet had all the tools to be a true performer when modified. The high-performance freaks we brought along argued that at the level they ride at, there wasn't a stock quad that could keep up, so they had to look at the underlying foundations to truly see which quad they'd purchase. We're going to test this theory in our follow-up comparison to see if they're right.
Bringing a stock 400 out to the dunes was like bringing a knife to a gunfight. However, despite having one of the smallest motors in the test, the way the Z/KFX made power pleased us all. With a wide spread of torque, the Suzusaki built to its peak swiftly, yet still had quite a bit of overrev. This aided in dune cruising immensely, as missing a shift didn't mean banging off the rev-limiter, but rather created a slow tailing off of power that gently reminded you to make your shift. Curiously for all-purpose bubble tires, the doughnuts on the Kawazuki (also present on the Raptor) were relatively better at sand than any other terrain. While they made the Raptor perform as if it wasn't top-heavy, they allowed the Z/KFX to use its power to its best advantage, digging and sliding in good proportion.
Big hills were a bit of work but ultimately conquerable with a bit of skill. Our test's lightest dry weight was a good advantage when flying off dunes, while the aforementioned overrev aided in sand surfing and kept the party going across dunes faces. Through all of this, the suspension acquitted itself well, if not stunningly.
The true test for the suspension came at Las Vegas Motor Speedway's motocross track. When the dust cleared, there were three consistent front-runners in every moto: the Cannondale, the Polaris and the dual-badged 400. It was said by one of the racers that the Z/KFX would go every bit as fast as the others, but you just had to work a lot harder to get it there. The motor was not as powerful as the others, but its power delivery helped to make up ground. The suspension was the best of the mass-produced units (Polaris used Fox Shox, and Cannondale used Fox Shox in the rear with Arvins up front), providing a soft but well-damped ride. The tires were the weakest link on the racetrack (but also the easiest thing to fix) because they dug in too much at low speeds and spun when you needed high-speed drive. Contrarily, slower testers thought the Z/KFX one of the easiest-to-ride quads on the track with its light steering and predictable handling. Racers agreed with this assessment to a point, but as speeds increased, some cornering instability became noticeable.
The most important test for the casual riders was the Z's performance on trails. Here, it impressed the most. The sweet motor endeared itself to all; the fast guys liked that you could really get on the KFX, while slower goers liked both its excitement factor and easy manners. Suspension that felt soft on the track was perfect on trails. Not quite the Raptor's match in rocky, mountain-goat terrain since the motor was not as snappy and the suspension was a bit shorter, it's still the next best thing. However, for overall aptitude in a variety of trail conditions, the Kawazuki came out on top.

At $5699, the Z400/ KFX400 tied for most affordable, which had visions of modifications dancing in our racer-boys' heads, while our neophytes were happy with the turnkey quad just the way it stood. There were concerns about how far one could modify a Cannondale or how much pounding the Polaris' transmission could take, and only the machine with no bad habits and nowhere to go but up came out victorious.
Kawasaki KFX400
Retail Price: $5699
Engine
Type: Four-stroke
Displacement: 398cc
Cooling: Liquid-cooled
Carburetion: Mikuni BSR 36mm
Lubrication: Dry sump
Ignition: CDI
Starting: Electric
Drivetrain
Drive System: Chain, 2x4
Transmission: 5-speed manual clutch with reverse
Suspension (Type/Travel)
Front: Dual A-arms/8.3 in.
Rear: Swingarm/9.1 in.
Tires
Front: 22x7/10; rear: 20x10/9
Brakes
Front: Dual discs; rear: disc
Dimensions
Wheelbase: 49.0 in.
Claimed Dry Weight: 370 lb
Ground Clearance: 10.3 in.
Length/Width/Height: 72.0/45.9/45.8 in.
Seat Height: 31.2 in.
Fuel Capacity: 2.7 gal.
Electrical
Taillight: Yes
Headlight: Dual 30-watt high/low beam
Instrumentation: NA
Color: Lime green
Suzuki QuadSport Z400
Retail Price: $5699
Engine
Type: Four-stroke
Displacement: 398cc
Cooling: Liquid-cooled
Carburetion: Mikuni BSR 36mm
Lubrication: Dry sump
Ignition: CDI
Starting: Electric with recoil backup
Drivetrain
Drive System: Chain, 2x4
Transmission: 5-speed manual clutch with reverse
Suspension (Type/Travel)
Front: Dual A-arms/8.5 in.
Rear: Swingarm/9.1 in.
Tires
Front: 22x7/10; rear: 20x10/9
Brakes Front: Dual discs; rear: disc
Dimensions
Wheelbase: 49.0 in
. Claimed Dry Weight: 372 lb
Ground Clearance: 10.3 in.
Length/Width/Height: 72.0/45.9/45.8 in.
Seat Height: 31.2 in.
Fuel Capacity: 2.6 gal.
Electrical
Taillight: Yes
Headlight: Dual 30-watt high/low beam
Instrumentation: NA
Colors: White, yellow