Project Suzuki LTZ400: HLS Suspension

Mar. 23, 2009 By Ricky Sosebee

2009 Suzuki LT Z400Page 1

Back a few months ago I got a look at a revised edition of my favorite sport ATV - the 2009 Suzuki LT-Z400.

Now this wasn’t exactly the fastest woods racer when it came out in 2003, but it rode nice and handled with potential. I had adopted the first yellow 2003 LTZ400 at my local dealership and with mounds of anticipation I took it home to prepare for my ride. The fuel was delivered via carburetion and it needed improvement by the industry’s expectations but for me it fit and that’s all that mattered.

In late 2008 the first fuel-injected Z400 came in sport/race fashion, looking similar to its MX brother - the Quadracer R450. This new revised version left us speechless to say the least. Some changes were spot-on, such as the powerful fuel injected engine and the awesome great looks. But there were a few function that we felt had been taken the wrong direction.

The suspension was our main concern with the 2009 version of the Quadsport. The spring rates were very stiff and this made the ATV really tough for a recreational rider to tame. As I had stated in my original review of the '09 Z400, there was a lot of tweaking at the ride site so each of the media could feel comfortable. Taking 4.5 rounds of preload out of the rear and all of the preload out of the front was a start for my size and riding style, but even after many adjustments it was still off. This is why we decided that the ride of the Z400 would be our first goal with a hands-on project.

We will be changing a few items to make this model fit our needs as a woods racer, with a budget mind set to keep our project affordable within reason. Our major changes right off the bat will include suspension.

You might say, “well that’s not going to be budget friendly”, but wait just a second. We have known of a company in Ohio for years that has recently taken their experience with ATV suspension and began to sell the expertise to the public. This company will not only make your Z400 ride smooth and plush, but in the fast tight woods it can handle like a dream. So when you rage through the woods with your friends rest assured that you will not be as sore or tired after this modification.

GT Thunder is a race-bred company that handles many top professional quad racers' engines and now suspensions. Located in Millersburg Ohio, the Sommer’s family and GT Thunder is all about the sport and they have developed many unique products. Our focus was on the growing demand for their suspension. As Lazarus Sommers would describe to me in a recent interview, his powerful engine modifications could not be controlled so he had to get a handle on the suspension of his machines in order to get the power to the ground. And that was the beginning with many years in the making of a new sister company to GT Thunder which is now called HLS.

Taking our stock shocks, Mr. Sommers set out to not only make the suspension feel more plush but to aid in the bottoming resistance, so that jumping the beast wouldn’t suffer damage upon landing. The removal of 7/8ths of the shock tube along with modifications to the shaft inside the shock will provide the rider with this much more travel and adjustability for the suspension.


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HLS also converted our single spring to a dual rate spring kit set-up. This will give a lower ride height that is key to getting the stock quad to handle corners better. The plush ride up top and less bottoming resistance for jumping your quad will make the rider more comfortable and potentially faster through the tight stuff. The front suspension was only the beginning though, as Laz and HLS would totally change the rear stocker to work along with the front.


The first change to the rear suspension was a GT Thunder special link that Lazarus has developed to change the leverage ratio and help lower the rear of the quad. The change in leverage ratio gives our Z400 more wheel travel as well. The engineers at HLS again, just like the front, shortened the shock tube/body to give the extended travel that is desired. This brings the rear of the 2009 Quadsport Z400 down and keeps the rider from getting into the bumpstop when hitting obstacles in the trails. This gets the entire bike sitting lower, cornering better and it makes a day of riding much more enjoyable.

All of this work will set you back $740 - and if you need stiffer or softer springs in the future Laz will change them out for you for free.


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So I'm guessing you might want to know how this changed our Quadsport Z400? The difference we noticed immediately is that the bike was sitting more evenly and much lower than in its stock form. The moment we sat on our Z400, I noticed how clean and smooth the feel of our suspension was. These were promising notes to take in mentally as we set out to test the new set-up.

In the tight stuff, the quad handled light years beyond the stock shocks, inspiring more ride confidence. This in turn initiated a slightly higher speed through the woods. Hitting obstacles in the trail didn’t make my teeth grind and I had to get used to the fact that it wasn’t going to come up through the bars as much. As far as jumping, I was able to bottom the suspension but it took much more effort to do so and when it did hit, the impact was reduced dramatically. Don’t think this change will keep you from bottoming out, but rest assured it will be very much less than in stock form.

The employees at GT Thunder and HLS Suspensions have created what most riders in our industry need today - Honest answers to your suspension questions, great rates for any budget and the knowledge of their work that has produced many off-road champions around the United States. Having a professional approach and knowledge to back it up will keep this company around for years to come.

Stock With HLS Suspension

2009 Suzuki LT Z400 with HLS Shocks

GT Thunder
6748 TR630
Millersburg, OH 44654
330-674-2437 - Fax

Revalve and respring all 3 shocks, linkage, and travel extension mod on the front shocks = $740.00 Newsletter
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