SUZUKI RM500
CYCLE WORLD TEST
More motor. Less motorcycle.
After riding Brad Lackey’s world-beating RN500 motocrosser (Cycle World, December, 1982) we had great hopes for the ’83 RM500. Brad’s RN500 had gobs of low-speed torque, a wide ratio four-speed transmission and super handling. The RN’s exceptional power and wide ratio gearing eliminated the need for more than four gears. Only two or three gears were needed by most riders.
We expected the ’83 RM500 to have a wide ratio transmission and power and handling somewhat like the RN500. It doesn’t. And we’re disappointed.
The new RM500 actually has more new parts and pieces than a casual glance reveals. Along with the larger engine, the forks are new, the rear suspension is changed slightly, the gas tank is smaller and the aluminum shift lever has a folding tip.
The RM500 engine is the result of boring the 465 engine 2.5mm. The 500’s 88.5mm bore combined with the 80mm stroke produces 492cc. The rest of the engine is mostly the same. Compression ratio is up slightly, also the result of the larger bore, from 6.1:1 to 6.2:1. The rod, crank, clutch, primary gearing and bearings are the same. Suzuki claims the 500 has a new wide ratio four-speed transmission. Comparing the 500’s transmission ratios to the 465’s tells the truth. Second gear has a slightly higher ratio. First, third and fourth are the same. Final drive gearing is slightly taller also, 14/47 on the 465, 14/46 on the 500.
KYB forks with 43mm stanchions and yellow lower legs yell New at potential buyers. They have adjustable compression damping and 11.2 in. of travel. Air caps are provided and oil weight and volume can be changed to suit different tracks and rider’s demands. The compression damper adjustment is located on the bottom of the slider. Eight damping choices are available by turning a slot-head screw. All the way in (clockwise, viewed from the bottom) gives the most compression damping, all the way out, eight full turns counterclockwise, the least.
An aluminum-bodied KYB shock is used at the rear.
It has four rebound damping positions. The adjuster wheel is at the top of the shock, under a protective rubber cover. Compression damping is
also four-way adjustable. The control is on the end of the remote reservoir and requires a flat blade screwdriver. The compression damper adjustment is easy to figure out; the end of the reservoir is numbered from one (the softest) to four. Number two is the standard setting and we liked it set at two, but, that’s why it’s adjustable. Different riding styles and different weight riders might like it on a different setting.
The RM’s Full-Floater rear is different than other manufacturers’ single shock rear suspensions. The other guys have rockers under the shock (except for Kawasaki’s Uni-Trak), the Floater’s aluminum rocker is above the shock. And the FullFloater is the only single shock system that compresses the shock from both ends. The Floater has been the best for several years; it still is, although the other manufacturers are gaining ground. The Floater has been fine tuned for ’83; the rocker shaft has been moved back slightly in the frame and the shock’s internal damping (the nonadjustable part) has changed slightly. The FullFloater linkage requires less greasing and maintenance than most single shock systems and it’s a good thing because it has to be pulled apart for greasing. It’s about time for the factory to install some grease nipples as standard ware.
RMs have had excellent hubs with straight-pull spokes for a couple of years. They are unchanged for ’83. The front brake is now a double-leading shoe stopper. In fact it’s almost more brake than most riders are capable of using. The earlier brake was very good. A good rider could stand an RM on its nose without crashing. The double shoe job will endo the bike easily if the rider panics and grabs a handful of front brake. The floating rear brake is unchanged and it didn’t need change; it’s strong> enough, doesn’t stall the engine easily and doesn’t chatter when used hard on rippled ground.
A couple of small parts have been changed for ’83. The shift lever is now aluminum and has a folding tip, Bridgestone tires are used in place of last year’s Dunlops, the seat cover is blue instead of black and the plastic gas tank only holds 2.0 gal. instead of 2.4 gal.
Other parts are familiar items; the chrome-moly steel frame still has a kicked-out 30° rake, although the frame has a new part number due to the different rear suspension rocker placement. The aluminum swing arm looks good and has proven strong. The cussed and discussed airbox, with dual oiled foam air cleaners, still requires the removal of a zillion screws to service. The big RM still has a bolt-on kick stand which makes trail riders and dealers happy and the racer can quickly take it off. Levers, bars and throttle are good parts that don’t need replacement before the bike can be raced.
Given the bounce test in the garage, the RM500 feels different. The short, flat seat and the dip in the tank, done so the rider can slide forward without needing the extended safety seat used by other brands, makes the RM seem smaller, less bulky than its rivals.
Ease of starting isn’t one of the 500’s good traits; the kick start lever doesn’t let the starter’s foot clear the sharp-topped footpeg. After the first try you become afraid of injuring your toes and have a tendency to kick too softly. Turning your foot out at the front allows your toes to clear the peg but subjects your instep to the end of the steel peg. It’s an unnecessarily painful experience any way it’s done.
Once started, the engine produces a definite vibration. Levers, bars and the seat of your pants buzz as the engine warms up. The transmission drops into gear with no clash or noise, and the bike takes off in a wheelie if you’re not careful. Low gear is quite tall but winds out almost instantly. Second and third are used up quickly and the bike tops out in fourth before most riders expect it. Long straights will have the rider trying to find another gear. The ratios are close and the bike comes geared for fairly tight tracks. Gearing up with a bigger countershaft sprocket is necessary for fast courses. The engine is responsive and quick revving. Power is everyplace but it’s not awesome like a YZ490 or KTM495. Rather, it’s usable for an average racer.
You probably won’t win any drag races to the first turn. You might out-brake the other racers going into that first turn, when you’re familiar with the front brake. But the guy on the CR480 Honda is going to be first out of the turn. The 30° rake and short wheelbase worked okay three years ago, it doesn’t work well against the 1983 crop of steeply raked, quick-handling motocrossers. The RM’s front wheel has a tendency to push toward the outside of the turn. If just a little too much throttle is used, or the throttle turned just a little too quickly, you and the RM are going to exit over the outside berm. An RM500 racer soon learns to use berms to turn the bike. It works well in them, stays where the rider wants, without trying to shoot over the top or dive low.
You can’t be lazy and race an RM500. It demands a lot of rider input in the form of weight shifting. Sitting in one place will put you at the back of the pack. The rider has to constantly move back and forth on the seat: on the top of the tank for corners, in the middle of the seat for regular straights, all the way to the back of the seat for high-speed straights with ripples. Riding on top of the plastic gas tank in corners isn’t as uncomfortable as you might suspect. The tank is low in back so it’s easy to slide up on and it gives enough to soften the impact.
The 500 is exceptionally good at blasting full speed through waist-deep whoops. The Lull-Lloater rear suspension doesn’t hop or dance around, the whoops just disappear. High-speed straights full of small ripple bumps aren’t handled as well. The RM500 develops a headshake, and it gets really severe if the bike is ridden as fast as the engine will propel it. No one got pitched off due to the shake but it is an unsettling feeling.
Summing up the RM500, the bike is only partially as good as it could have been. Suzuki certainly has the technology. Riding Brad Lackey’s bike proved that. Modern motocrossers no longer have the luxury of staying the same, or almost the same, for three or four years. Staying competitive means getting the hard-earned and expensive facts learned at the racetrack integrated into the production bikes. And it has to be done quickly. Otherwise the other manufacturers will win all the marbles.
If the ’83 RM500 had the wide ratio four-speed transmission it’s claimed to have, the bike would probably be competitive. With a wide ratio transmission and a pulled back, steeper rake angle to quicken steering and handling response, the RM500 could be in the hunt for best 500MX. As it is, the RM500 is okay but rather average, and races aren’t won by average bikes. E9
SUZUKI
RM500
$2399
SPECIFICATIONS
