Turning Quadzilla Into A Killa
TURNING QUADZILLA INTO A KILLA
A SIDE FROM BEING humiliating, our first assault on the hill taught us an important lesson: that if the Quad were to make a serious attempt to get anywhere near the top, it needed vastly improved suspension and more horsepower.
On the other hand, we didn't want to end up with a hillclimb-only ATV, either. We wanted the Quad still to be usable for playing on the dunes and general trail riding. So our strategy was to emphasize the strengths of the stock 500 Quadracer— namely, its incredible torque—but not at the expense of its all-around capabilities.
So, we contacted Wayne Mooradian at Performance Engineered Products (PEP), the company that does the suspension work for most factory ATV racing teams. A company with those credentials, we figured, could be trusted to give the big
Quad the suspension it needed. First thing, Mooradian removed the front shocks and anodized the bodies. After installing gas-
charge fittings, he pressurized the shocks with 100 psi of nitrogen. They were then reinstalled with the stock springs set on the second preload position.
Mooradian also attacked the rear shock, anodizing the body before charging it with 165 psi of nitrogen. He retained the stock spring, and set the preload to yield four inches of suspension sack. For a final touch, he installed a PEP steering damper up front.
Next, we delivered the Quad to Rusty Hadley at Suzuki Country Racing (SCR) for the engine work. SCR offers five ever-more-radical kits for the big Quads, and Hadley felt the Stage Four kit would be perfect for our needs.
Stage Four begins with a big-bore kit that increases the displacement to 530cc, with porting that increases both torque and horsepower. The carburetor undergoes a 38/4 1mm boring, meaning that below halfthrottle, the carb venturi is the stock 38mm, but increases to 41 mm above halfthrottle. This allows the engine to retain crisp bottomend response, but with an increase in full-throttle flow for more top-end power. In addition, Hadley stuffed in a set of SCR reeds to further increase bottom-end response. He retained the stock air-filter, but took the top off of the airbox. Last, Hadley fitted a pipe and silencer manufactured by Bill’s.
Once we got the Quad back in our shop, we had a few tricks of our own up our sleeves. One was the installation of an Answer Products Roost Boost. The stock ignition won’t let the Quad rev very highly, but the Roost Boost took care of that. We also we slipped on a Cobra Engineering Sparky, which is a U.S. Forestry approved spark arrestor, and replaced the stock thumb throttle with a Suzuki RM twistgrip. Finally, we mounted a pair of Mitchell aluminum wheels on the rear, fitted with a set of Sand Tires Unlimited four-ply Padla Brat paddle tires to help the Quad dig its way up the big, loosely packed hill.
The very first time we rode the hot-rodded Quad, we knew we had succeeded in meeting our goals. The suspension is considerably better than stock, and, frankly, even better than we expected. In our opinion, PEP’s suspension work is the single biggest improvement you can make to a stock Quad 500. The rear end now tracks straight in the deepest whoops, and we no longer feel the smaller bumps. Most important, the rear wheels stay planted over rough terrain under hard acceleration, and the machine no longer pitches from side to side.
And that’s a good thing, because the engine puts out a bunch more horsepower than it did when stock, and at all rpm. The power is noticeably stronger way down low, and pulls harder all the way to the top. But amazingly, the engine is still so mild-mannered that it never makes us feel like we’re riding a hopped-up open-class ATV. There’s no question, then, that this project has been worth the expense, Largely due to the work done by PEP and SCR, we couldn’t be happier with the 500. In every way, it is a significantly better machine than it was before, and is much more fun than ever to ride. It’s fully deserving of the new name we have given it: Killa Quadzilla.
Camron E. Bussard
