Suzuki Rm8oz
SUZUKI RM8OZ
CYCLE WORLD TEST
A Full-Fledged Racer For the Champion of the Future
■ Tension mounted as the 10-sec. sign came up. Riders pegged their throttles, crouched over the tanks, eyes focused on the starter. The gate dropped and 20 bikes shot off the line. Six bikes
bumped, shoved and locked bars into the first turn, a turn three bikes wide. Somehow they all made it. Next, a big jump. The three leaders went over together, four feet in the air and cocked sideways in preparation for the tight turn. An open-class national? Final event in the Supercross series? Nope, just another local race between 80cc minis.
Minis began as toys, kiddi-cycles with little wheels, lawn mower engines and handling that made you close your eyes. The kids loved it anyway, and minis became a family sport, with mom and the neighbors cheering while pop could tune and coach and not have to show up for work Monday with his arm in a sling. Minis are good fun, good racing and good business, so during the past few years the factories have created two lines of small dirt bikes. One set for play, and one for racing. Competition between the factories is just as serious as it is with the larger displacement motocrossers. Virtually every manufacturer of 80cc racers is offering a single rear shock motocrosser for ’82. Suzuki’s RM80 looks much like its bigger brothers, right down to its Full-Float->
er rear suspension. Close inspection of the rear suspension shows several differences; for instance the only adjustment is spring preload. The biggest difference is in the rocker and strut arrangement. The struts cant forward and connect to the front of the rocker, not the rear. The rear of the rocker is bolted to the shock, just the opposite of the larger Full-Floaters. Thus, the struts are protected from crashes and the back end of the bike looks less cluttered. After inspecting this linkage, we wonder why the larger bikes aren’t the same. Anyway, the shock sits vertically behind the engine, bolts to brackets on the bottom of the swing arm, and to the rocker at top. The rocker is strongly mounted in the frame and pivots on a bolt that goes completely across the frame. Bracing is good around the pivot and the low mounting position on the swing arm keeps shock weight low
on the bike.
The swing arm is rectangular steel tubing painted silver to resemble guess-what. But it’s long, which is good for traction and it looks strong. Minis are subject to lots of stress and the RM80 frame is beefy, designed for the bike’s performance rather than for its engine size. The backbone tube is large and well triangulated, the front downtube starts single, splits into a wish-bone to clear the center exhaust port, then rolls under the engine and back up to the shock pivot area. Rear sub-frame tubes are also large and look strong enough to withstand the normal rigors and crashes associated with mini racing.
Forks are leading axle racing items with the same wheel travel as the rear, 8.3 in. Triple clamps are up to the task with large pinch bolts and a wide gripping area.
Wheels, rims and tires are scaled down models of larger RMs. The hubs are center-pull spoke designs, spokes are big enough, rims are aluminum and the IRC tires work well. The front wheel is a 17 incher, the rear a 14 in.; standard mini racing sizes.
Plastic components, fenders, side panels and tank, are designed to look similar to big RMs and do their job nicely. The seat is thick and the right width.
All these parts are powered by an 82cc engine with a 49mm bore and 44mm stroke. Carburetion is via a 26mm Mikuni through a reed valve. Six transmission speeds are standard and needed for the race-tuned cylinder.
Our expert mini tester normally races a KX80 but liked the RM as much. “The RM is very pipey and it’s necessary to use the clutch a lot to keep the bike on the pipe, but it’s faster than my KX. Gear
ratios are good but the bike isn’t geared fast enough for faster tracks.” His dad installed a one tooth larger front sprocket, which they felt made power application to the rear wheel better as the rear tire didn’t spin as easily, and the bike had adequate top speed.
Suspension gave mixed reactions. “The forks are perfect with 6 psi but the rear bottoms,” says our 107 lb. racer. Adding more spring preload helped but a heavier spring may be needed for fast or heavy riders.
Both brakes worked well but rocks got wedged between the front brake arm and the backing plate on several occasions. No complaints about the rear brake; it was strong enough and didn’t chatter or lock-up.
Carburetor jetting was off quite a bit for our area (around 1000 ft. elevation). It was necessary to use a smaller main jet and drop the needle one position. Spokes front and rear loosened a little the first couple of rides as did the rear sprocket
bolts. No problem after that. The chain didn’t stretch excessively and the large size seems more than adequate for racing demands. The kick starter is easy to use if you’re mini-sized but ours kept falling out of position while riding. It sometimes happened without the rider’s knowledge until he would move his weight to the rear of the bike and his leg would engage the mechanism. He didn’t explode any internals as a result but it’s possible.
All in all, the RM 80 is a good racer. And it is a full-fledged racer. Don’t mistake this or any other mini-motocrosser for a trail bike. In the hands of an expert sure, but even then, a trail model would be better. The RM80 is a highly tuned racer with little low-end power, the kind needed for trail riding. The exhaust is noisy and it doesn’t have a spark arrester. As a racer, it has competitive power, handling, brakes and looks. And best of all little or nothing will need changing before the RM80 racer can charge into the winner’s circle. 83
