Quadzilla Details

The Suzuki LT500R "QuadRacer" is more commonly known as "Quadzilla" in the ATV community. It is the big brother to the smaller LT250R "QuadRacer". Both QuadRacer models share similar design features adapted to high-performance racing conditions and they each sport the same yellow and blue color scheme, but share very few components which are not interchangeable. The easiest way to differentiate these two models from a far is by identifying each QuadRacer’s blue, radiator grille. The LT500R’s grille features a single vertical vane through the center, while the LT250R’s grille features two vanes that are oriented horizontally.

The Quadzilla was offered only during the 1987 through 1990 model years. This fact makes it difficult to acquire a Quadzilla from the used market, and very difficult to find one in new condition. The 1987 Quadzilla product was known as the "H" model, 1988 was "J", 1989 was "K", and in 1990 it was "L". For example, sometimes you will see a 1989 Quadzilla identified as an LT500RK. The 1987 "H" model appears to have been sold in greater quantities than each following model year. This observation is ironic due to the fact that the 1987 model had a different powerplant than all of the following years. The 1988 "J" model featured the second-generation Quadzilla powerplant. This new engine appears to follow the same general specifications as its predecessor, however proof that it is different lies in the fact that components are not interchangeable and transmission gear ratios are different. In 1989, the "K" model received some chassis refinements. These refinements’ presence can be easily identified by white-colored A-arm front suspension, replacing the former silver-colored A-arms of previous years. In 1990, the "L" model received even fewer changes. I suspect the changes in 1990 were in response to manufacturing cost considerations.

The rear shock (damper) is manufactured to Suzuki specifications by Showa. This Showa damper used in the Quadzilla was found on Suzuki's RM line of MX bikes in as early as 1984. While the rear damper is rebuildable, the front dampers are not. Although the front dampers are not rebuildable, it is still possible to modify them to perform differently.

The Quadzilla remains, to this day, Suzuki’s largest-displacement and greatest-powered ATV. A new Suzuki ATV model, not to be confused with the Quadzilla, was introduced in 1997. It is identified as the "LT-F500". This new ATV is not a member of the QuadRacer family, has a smaller engine displacement figure, and far less horsepower than the Quadzilla does.

I have found much improved power on my own 1989 LT500R through improving intake flow. First thing, remove the air box lid, you won't be needing it any more. Increase the main jet to #440 and the low speed jet to #22.5. You will likely find that #440 may be a little too much on the safe (rich) side. I typically rode with main jets varying from #430 to #410 and always premixed my oil at 32:1 for use with those jets. I should also add that it is important to use the same premix ratio to get the same air/fuel ratio and don't ride with the lid removed using the original #350 main jet, engine damage can occur.

Suzuki Motor Corporation released the following specifications for the LT500R. As of this writing, only the wheelbase is confirmed slightly different across model years.

Displacement: 499.5cc
Bore & Stroke: 86mm & 86mm
Compression: 7.2:1 (corrected 6.3:1)
Carburetor: Mikuni TM38SS, flat slide
Lubrication: Oil premix
Ignition: Suzuki PEI (CDI-type), 4° @ 1,000rpm, 12° @9,000rpm
Starter: Primary kick
Transmission: 5-speed, manual clutch, no reverse
Transmission ratios: primary 2.142 (60/28), 5th 0.909 (20/22), 4th 1.100 (22/20), 3rd 1.333 (24/18), 2nd 1.733 (26/15), 1st 2.416 (29/12), final 3.076 (40/13)
Final Drive: #520 chain, O-ring sealed
Overall Length: 1,920mm (75.6")
Overall Width: 1,205mm (47.4")
Overall Height: 1,110mm (43.7")
Seat Height: 790mm (31.1")
Wheelbase: 1,345mm (53.0")
Ground Clearance: 110mm (4.3"), at rear axle
Dry Weight: 178kg (392 lbs)
Fuel Tank Capacity: 13 liter (3.4 gal) including reserve
Front Wheels: AT21x7-10 fully corded tires on aluminum rims, using 4 on 166mm bolt pattern
Rear Wheels: AT20x11-10 fully corded tires on aluminum rims, using 5 on 130mm bolt pattern
Brakes: triple hydraulic disk, single piston caliper designs
Front Suspension Travel: 9.1", double A-arm with adjustable preload and 4-way rebound damping
Rear Suspension Travel: 9.1", "Full Floater" linkage, adjustable preload, 21-way compression, and 26-way rebound (SLR 2.11:1)
Caster: 10°
Camber:
Trail: 42mm (1.7")
Toe-in: 11-19mm (0.4-0.7")
Turning Radius: 2.8m (9.2')
Turning angles: 32° inside, 25° outside (±3°)
Fuel: 85 octane pump fuel (R+M)/2
Warranty: three-month