Suzuki LT500R by Duncan Racing

Suzuki’s LT500R is the stuff of ATV legends. Think a four-stroke 450 is fast? Imagine the performance potential of a 500cc, liquid-cooled, power-valved two-stroke! Most of today’s riders can’t even comprehend what a machine like that would be like, but Suzuki offered the mighty 500 from 1987 to 1990. Its massive power earned it the nickname “Quadzilla,” and it developed a following that’s still going strong today. Duncan Racing (DR) applied the best of today’s performance technology to the legendary LT500R and invited ATV UTV Action to experience the results.


There’s no question that the LT500R was the most shocking high-performance sport quad of its time. But like most machines from the late ’80s, it was far from perfect. Modern sport ATVs have better engine and suspension tuning right from the dealer. Duncan Racing strove to dial the Suzuki in and give it the balance and handling of a modern quad while they built on and refined its incredible engine performance.


Suzuki’s liquid-cooled, reed-valve, power-valve 500 was a state-of-the-art two-stroke for the late ’80s. Though reed valves were common on twostroke ATV engines at that time, power valves (variable exhaust ports) were rare. Duncan Racing developed its Paul Turner National LT500R engine kit to cure the stock 500’s breathing and jetting problems while unleashing the full potential of the high-performance engine design.


Duncan Racing’s clamp-on air filter retains the stock airbox, but eliminates the stock intake’s sealing problems. A DR-modified and pre-jetted Keihin PWK carburetor and Pyramid reed valve replaces the less-advanced, flat-slide, stock, Mikuni carb and stock reed cage to improve throttle response, boost power and simplify jetting. The LT500’s stock porting and cylinder head shape limit the engine’s performance and make destructive detonation hard to avoid. The Paul Turner/DR porting and head increase power and reliability. The Suzuki’s stock exhaust limits breathing and power output even on the stock engine. A DR/Paul Turner pipe and Fat Boy 2 silencer make the high-performance engine run stronger and cooler. A DR clutch kit with a Hinson clutch basket reliably transmits all the power to the rear wheels and is far more durable than the stock clutch components.


The Quadzilla is one of the most powerful ATVs ever made, but like most ATVs from the late ’80s, its stock shocks weren’t even as good as some of today’s trail quads. DR brought the Suzuki’s suspension in line with its engine performance with Elka Stage 4 shocks. These shocks offer adjustable high-speed-compression damping, low-speed-compression damping, rebound damping and spring preload. They’re also rebuildable and re-valvable. Duncan Racing sets up each set of Elka shocks individually to suit the rider, the machine and the riding conditions the suspension will be used in.

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DR prepared the LT500R we rode for dune riding with a 2-inch-plus Laeger swingarm and Skat-Trak paddle tires on Douglas wheels. The Laeger swingarm helps keep the Quadzilla’s front end on the sand under hard acceleration and includes a convenient Honda-style chain-adjustment system. It also eliminates the cracking problems that affect the stock Suzuki swingarm as age and hard use take their toll.


The LT500R was built for performance- crazed riders, with no concessions for curiosity-seekers or posers. There’s no electric-start button and no reverse. You have to kickstart this machine, and you have to be ready to kick it like you mean it. The Duncan Racing LT500R starts with one or two kicks because it’s so perfectly tuned, and it even idles like a trail quad—even the sound of the 500 idling is enough to give you chills. It’s like shotguns going off in the distance.


Click the Suzuki into gear, ease the clutch out, and the big motor moves the machine like it weighs nothing. A little throttle provides so much pull you really pay attention to where you’re pointed before giving it more. A run through the gears leaves no doubt the machine could leave a new, strong-running four-stroke 450 in a haze of roost and two-stroke race-gas exhaust. Once we got accustomed to the 500’s crisp, forceful acceleration, it became clear how clean-running and controllable it is. We’ve ridden stock LT500Rs and though they’re powerful, they don’t respond as well or pull anywhere near as hard.

The Elka suspension took no getting used to. It was gloriously smooth—even at low speeds—and seemed to have a limitless ability to handle big impacts and jump landings. If you’re lucky enough to own a Quadzilla and are still riding it with what’s left of its original suspension, Elka shocks can make the machine more enjoyable than it has ever been.


Riding a legendary two-stroke high performance quad is always a special experience. Riding one that’s carefully tuned and prepared by one of the country’s top performance shops is incredible. Duncan Racing enlarged all the greatness the Quadzilla is known for and removed its rough edges and weak points. The DR LT500R is better than the legend ever was.

Duncan Racing, International
10734 Kenney Street, Suite A
Santee, CA 92071
(619) 258-6306
(619) 258-6309 (fax)

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