When the QuadSport Z400 was released back in 2003 by many trade publications, it was heralded as the best performance quad on the market, and it proved itself in the racing sector with many championships. It had a one-year-reign as king until Yamaha released the YFZ450, shortly followed by the Honda TRX450R, and even with those releases, Digger Doug Gust still won the GNC championship in ‘04 aboard the Suzuki. By 2005, with racier quads available, the Z somewhat slipped off of the performance radar.

Now in 2009, with all of the 450’s and several larger more powerful quads on the market, the Z400 may or may not be the best quad for you depending on your goals. For this project, we took the current fuel-injected 400 and didn’t try and re-make it into a race machine as we would have five years ago, but rather took it for what it was and refined it to meet our intended uses.

The Suzuki is a great all-around trail machine, having a smooth power curve (even more linear than past models), but still lacking in HP for aggressive off-roading and trail riding. In stock trim it’s several horsepower down compared to all of the stock 450’s on the market. To tune it up, we went to CT Racing for their Sonic Pipe. The exhaust system is quiet at 94 dB, and can be reduced even further by simply removing a couple of the spark arrestor discs. It also comes tuned for maximum HP with a spark arrestor.

With the addition of the CT pipe and removal of the air box lid, we found the quad ran lean, so a Dynatek FI fuel management system was added, along with a Pro Design Pro-Flow foam filter. We dyno tested the Z400 and came up with 40.18 rear wheel ponies. This makes it comparable to the top two of the eight stock 450’s in terms of horsepower, and give us what we needed for a rideable trail machine.

Suspension in stock trim was made to work for a wide range of riders. The problem is that it’s not good for anyone that rides at a good clip. You need to have it set up for yourself in order to have the best quality. We wanted a plusher initial action to give a smooth ride over the small stuff, better weight transfer and better braking over small bumps. We also wanted something that would cover up our mistakes (hitting stuff faster than anticipated) and take some big hits. We went to Noleen J6 to work over our suspension. Clark Jones, owner of Noleen J6, took our stock shocks and gave them a serious tune up. Clark took the stock fronts, revalved the internals and converted them to a two-spring shock; the top short spring to give us that plush ride and a stiffer main spring to help keep it from bottoming. The rear was also revalved and re-sprung, but still uses a single spring setup. The type of action we expected from the Suzuki didn’t warrant thousands of dollars in purchasing complete shocks. Comparatively, the work we had done turned out great and cost a fraction.

Trail quads are usually ridden for extended duration. We concentrated on ergonomics and things that could help us stay comfortable during long rides. We went with Fasst Company Flexx bars. These have elastomers integrated into the design that flex and absorb energy. The energy absorption takes away a high percentage of the jarring that would normally go to your arms, elbows and upper body. We went with ASV levers (which are virtually unbreakable), and they have a very good pull ratio on the clutch making it easy to engage, and are adjustable for hand size. Having the lever adjusted for correctly can have a large impact on reducing energy that it takes to pull the clutch and brake. Combine this with less impact and the result is greatly reduced fatigue.

We went with Spider grips; they are tough, offer good traction even in wet conditions, and are slim. We also added Streamline brake lines. The stainless steel braided lines offer much firmer braking by eliminating the bulging of the stock rubber lines. Anyone that rides fast off-road knows how important a steering stabilizer is. Riding at speed it can help save a lot of energy. We went with an RTT Stabilizer, which mounts down at the bottom of the steering stem. It is adjustable on the fly with a bar mounted lever.

Extras:

We couldn’t find a graphics kit for the QuadSport Z, so we just took the CT Racing LTR 450 graphics kit and it fits pretty darn good - the seat cover fit perfect. Maxxis Razor 20/11 9 and 21-7/10 fronts were thrown on. These are tough tires, proven in countless GNCC and Baja wins, as they add a lot of stability with a more rigid sidewall allowing full slides through the corners and better overall handling. We added OMF ringed wheels to give us a little added durability. With the ringed wheels you can slam into more stuff, hit rocks, and the wheel doesn’t fold up, keeping air in the tire, and that’s a good thing! 

UM Performance Products offers a nerf bar that has a built-in heel guard and comes with a pro peg setup that is very wide, offering more foot support and a bit of a kick up at end of the peg so your foot won’t slip off of the outside. We used their front bumper, belly skidplate and swing arm skidplate. Every piece fit well and looked good.

After a day testing the Z400 in the SoCal high desert, we added a little motocross time for good measure and came away wanting more seat time on the little Suzuki. We were actually thinking about how cool this thing would be to race in the next Glen Helen 6 hour! It does everything well - it’s not arm-wrenching fast, but runs well. It’s very stable in the corners and doesn’t leave you wanting a wide axle. The Maxxis tires and Noleen suspension were quite at home on the MX track. Make sure to watch the 2009 Suzuki QuadSport Z400 Project ATV video where you can witness how well the Suzuki handled through gnarly whoops and just how flat it stays through high speed corners.

Living in an ATV world now overrun with 450-class megawars, it’s easy to forget about Suzuki’s all-‘rounder. The Z400 has been making a lot of quad enthusiasts happy over the past years and enough aftermarket support is available to make it as wicked as you want. The goal of our project was to rediscover this great do-all ATV and see if it still has what it takes to show riders a good time. With the help of all our supporters, we’re convinced that this mid-size sport quad isn’t done yet.