Suzuki Z400
Back in June, Suzuki made vast changes to the already popular Z400 sport ATV. When we had our chance to look at it for the first time, there were plenty of reasons for us to be impressed. The biggest and most notable change was the introduction of a fuel-injected powerplant that caused many heads to turn. Suzuki claimed the engine put out a significant amount of power across the board, which left it beginner-friendly with options of upgrading in the future.

Another major change for the Z came in the form of a new suspension package. The front of the quad was widened by an inch and the shocks were sprung and valved in a way that was similar to that of the LT-R450. The reason engineers at Suzuki went in this direction was that in their research they found that the average Z400 owner/rider used this machine not only as a recreational trail or dune quad but also occasionally raced it. The Z400 has definitely proven to be competitive in the past, and Suzuki wanted to make a product that was a little more geared toward this group.

Anxious like a kid on Christmas morning, I threw my leg over the new Z with plenty of expectations to be filled. In the department of the engine, I was definitely happy. There was much more of a pull on the bottom and in the midrange of the powerband, which was exactly as claimed. The suspension department is where I felt the engineers' upgrades went in the wrong direction. In an attempt to make a recreational sport ATV that was capable of being raced, the suspension was made far too stiff and I felt it a bit unpleasant to ride. Although the front end was wider, the machine still felt tipsy, and the front end severely pushed in the corners and didn't track very well in rough terrain.

What To Do?
I thought long and hard about what I wanted this quad to do and where I wanted to do it. My first thought was to make a better handling trail machine but one still capable of racing a grand prix or motocross race. Since I'm stationed on the West Coast, keeping the machine narrow isn't so much of a necessity as it would be for racing on the East Coast. This meant I could make it even wider for good stability on some of the faster off-road trails that cover my local riding areas. Additionally, I wanted the controls on this machine to suit me a little more. The steering stem has been shortened this year, and at 6-foot-1 I want this quad to fit my frame a little better. Not that this is a big negative for the Z, because this is a mod that I usually end up having to make on all sport ATVs.

After all of the hype around the suspension upgrades I was relatively disappointed. Since the Z was released, it has been known as a great trail machine with race possibilities, but redesigning it to be more of a racer out of the box took away its comfortable trail riding characteristics. That's when the wheels in my head began turning to figure out what needed to be done to make this new and improved machine better than ever. I presented myself with a challenge and was ready to take it on.

With suspension being my primary focus, I turned to a company that has been in the business for many years and in my eyes understands suspension like no other. Doug Roll of Roll Design has been making ATV suspension for years, and his products have been seen on almost every factory race quad at one time or another. I explained to him what my goal was for this Z, and he set me up with one of his Lobo II long-travel suspension kits. Not only would this kit widen the track of my Z to 50 inches, but it would also increase the wheel travel and overall handling on all terrains.

Doug wanted to ensure that this suspension would work at its best, so he handled my shock setup on this project as well. He made a call to Martin Lamoureux at Elka Suspension and ordered a set of its Elite front and rear shocks. These shocks are some of the best on the market and feature high- and low-speed compression, rebound and preload adjustability so you can fine-tune your machine for deep whoops, large jumps or for a lazy day out on the trail. The box for the rear shock also featured Elka's replacement shock linkage, which offers more wheel travel, improved geometry and better progression throughout the travel than the stock unit.

With the suspension being handled, I was ready to address the issue of controls. To simplify my list of components, I also went with a Roll Design +1 anti-vibe steering stem and a set of its oversize handlebar clamps. This combination with a Renthal Twinwall bar put the controls right where I needed them to be. To keep the bar from being jerked out of my hands in hostile terrains, I also opted to mount a GPR low-boy steering stabilizer. After a long day out on a rough track or trail, your arms really appreciate this feature. Finally, rounding off my list of parts that I could acquire from Roll was a complete set of wide footpegs, nerf bars and heel guards. The nerfs are a must if you ever decide to do any sort of racing, and the combination of footpeg and heel guards ensures that your feet never leave the quad.

The Fat Boy 4 HQ exhaust made great power while keeping the sound at a minimum, and the GPR Low Boy stabilizer minimized the hard impacts felt through the bar.

To round out the stability of this quad, an adjustable rear axle was added to the list. For this part, a call was put in to Team Industries for one of its Firestick axles. Not only are these axles wider and offer adjustment from +1 to +2 per side, but they're also significantly stronger and less prone to break upon harsh impacts. So far the project is right on track for being transformed into what I would consider a great trail machine.

While I did claim the engine had plenty of power for a stock machine, I'm always open to getting a little more. I opted to run a Duncan Racing Fat Boy 4 HQ exhaust system in conjunction with a Pro Design Pro Flow filter kit and Two Brothers Juice Box EFI programmer. I've always been a fan of the Fat Boy 4 because of its looks and quality, and the HQ is longer than the standard model to help decrease sound and keep our riding lands open. The Pro Design Pro Flow comes with a billet flange, K&N filter and Outerwear that allows more air in to make even more power and better air filtration.

The Two Brothers Juice Box was used for two reasons. First, at the time of this build Duncan Racing did not yet have its own model ready. Second, I wanted to show the versatility of the Juice Box. While the unit already comes preprogrammed for Two Brothers' own exhaust, I was able to adjust the fuel mapping for the Duncan exhaust system and have the Z running at peak performance with minimal effort. If you have one of these quads with an exhaust system already on it but don't have the fuel controller, make sure you get one of these. They're simple to install and increase the performance gains you will see.

Getting the power to the ground was done through a set of Renthal chain and sprockets as well as a set of new ITP Holeshot SR tires mounted on T-9 Pro Series Baja front wheels and T-9 Trac-Lock beadlock rear wheels. The SR-model series of tire offers the great performance of the tried-and-true Holeshot while including the benefits of a radial tire. The front wheels have a reinforcing ring welded on so I'll be less likely to bend a rim, which I'm definitely known to do. The beadlock on the rear keeps the wheel from coming off the bead while running lower pressures and provides more strength as well. The combination of these parts should not only perform well, but also give this machine a very unique look. A set of genuine Suzuki skid plates was added to protect the frame, link and swingarm and I was finally ready to roll.

Trail Tested!
To give all of these parts a good punishing, I went to a testing area in the mountains east of San Diego, California. This location had everything from windy boulder-laden trails to fast, high-speed straightaways that'll test every aspect of this machine. As soon as I sat down, the change in height from the steering stem and handlebar felt great and was as welcome as the cushy seat and cover from Quad Tech-ATV. A quick push of the start button and a throaty roar came from the exhaust. I was defiantly ready to hit the trails.

The power felt from the modifications to the exhaust and intake systems was definitely noticeable. What used to be good on this stock motor was now great, and the quad felt closely comparable to a stock 450-based ATV. Throttle response was instant and led into a strong pull that never seemed to flatten out. As I was pleased with the results of those modifications, I was ready to see if my suspension upgrades would give the same results.

The first trail I veered down started with a series of high-speed flat and banked turns with the occasional off-camber downhill. As I blazed down the path, the quad went exactly where I pointed the bar and my previous complaints of an ill-handling machine were now nonexistent. The front end never pushed, but stuck to the ground and allowed the Holeshot SRs to bite into the ground and give me a feeling of being on a roller coaster at Six Flags. The plushness of the suspension along with the wide track made this a very predictable handling machine that did exactly what you wanted it to.

As I proceeded down the trail I came across obstacles that could give even the best GNCC racer a tough time. Although I didn't go through as fast as they probably could, the nimble Z hammered through with no problem. The ITP wheels and tires definitely took a beating through sections like this, but that is why I went away from the stock rubber to a good set of quality four-ply tires like the Holeshot SRs. All in all, I was thoroughly impressed with the way this machine turned out.

The End Result
Just because a manufacturer comes out with a "new and improved" model doesn't necessarily mean that it works as good as it should. Sure, the engineers at Suzuki had all of the best intentions when they revamped the Z400, but some of their ideas went too far in one direction, which made a machine less of what it was known for: a sporty ATV that is suitable for all skill levels and riding styles.

What I proved with this project is that with simple modifications this machine is capable of being a formidable race ATV while still being a capable trail machine. Although with the mods we've done it isn't the best choice as a GNCC racer because of its width, I'm sure it could still hold its own. For anything held on the West Coast, I wouldn't have a second thought about lining up for a GP or MX race on this machine. It's not as fast or powerful as a 450, but it can definitely outhandle some of those machines on the track.