Suzuki Rm125
SUZUKI RM125
CYCLE WORLD TEST
The better they are, the harder they are to improve.
The problem with being the best of anything, is that there's only one way to go. You can get worse and everybody soon knows it. They're looking for it. Stay the same or improve and nobody notices. Suzuki's RM125 has that problem. For the last couple of years it has been the best 125 motocrosser available out of the crate.
In that time it's been updated and re fined, but it has looked, for the most part, the same. Same liquid-cooled motor. Same Full-Floater rear suspension. Same yellow. This is now the third year of this same basic motorcycle. There have been changes made. But these changes aren't visible.
Most visible are the bright blue seat cover and the yellow fork sliders. Inside those yellow forks are more new parts. The 38mm KYB forks have adjustable compression damping. An adjustment screw, protected by a rubber cap, is lo cated at the base of each fork leg. The screw tensions a spring-loaded pop-off valve that limits compres sion damping. The screw has eight adjustment positions. There are clicks or stops. Instead, screw the adjust ers all the way in and that's maximum compression damping. Turn the screw out four full turns and it's in the middle of the range, the standard setting. An other four turns out is minimum cornpression damping, which worked best during our testing. The screw can be turned out more than that, but has no effect.
Rear suspension parts have undergone similar changes. The aluminum-bodied shock has new internals and adjustable compression damping has been added. A flat-blade screwdriver moves the adjuster screw on the remote reservoir to any of four settings. Four rebound damping settings are still provided by turning a wheel on the top of the shock body. Spring preload is still adjusted with a threaded collar at the top of the shock body. Shock oil can be replaced and the excellent owner’s manual explains the operation.
Rear wheel travel has grown from 12.2 to 12.5 in. The extruded aluminum swing arm is an inch longer and the aluminum rocker at the top of the rear suspension has been moved back an inch to change the rate of progression. This makes the Suzuki even better when landing after a giant jump.
The rear suspension configuration is still the same. A large spring-shock is placed at the forward end of the swing arm. The bottom of the shock is compressed by the swing arm. The top of the shock is compressed by the top rocker, which is being rocked by à pair of aluminum uprights extending from the swing arm to the rear of the rocker. With both pivots moving, there are no side loads on the shock. The shortcomings of this design, as used in the RM 125, are the restrictions in airbox room and the distant placement of the shock reservoir, above the radiator, on the lefthand side of the bike, where it is connected to the shock with the world’s longest oil hose.
While the suspension has been revised, the engine has been left mostly alone. It still has a 54mm bore and 54mm stroke. It’s still a reed valve, liquid-cooled twostroke. The radiator is still mounted on the frame downtubes, and there’s still a small water pump on the righthand side of the engine. What’s been changed is the porting and the flywheel weight. Small motocrossers have peaky motors. We all know that. They require great agility, cat-like reflexes and tremendous coordination and skill to ride fast, but when wound out and shifted fast, they are quick.
So Suzuki has gone and tamed the RM 125 motor. Lower cylinder ports and a heavier full-circle flywheel makes the RM 125 work better at lower engine speeds. It’s easier to ride. It just isn’t as fast.
The rest of the engine is the same. The 32mm Mikuni carb is still there, and it still has six speeds in the transmission, but first gear has been raised slightly to take advantage of the greater mid-range power.
Shifting is now done with a forged aluminum lever, which naturally has a folding steel tip. Other new parts include the smaller 1.7 gal. plastic gas tank, replacing the 2.0 gal. tank, and the IRC tires in place of the Bridgestones used last year.
Many parts haven’t been changed, and some should have been. The wheels and straight-pull spokes are the same, and so are the brakes. This means the RM 125 doesn’t get the double leading shoe brake that’s used on the new 250 and 500cc motocrossers. That double-sided airbox is still used around the rear shock, which isn’t one of the better solutions to the packaging problem. And Suzuki’s front fender is awful. It’s too flat, allowing mud to be flung around the edges and into the rider’s face, and it is also likely to break during muddy races.
Plastic parts, accessories, even colors may not have a lot to do with how fast a motocross bike can run or how it steers, but it does a lot to entice a rider onto the bike. And here the Suzuki falls down. No longer is it the most exciting-looking motocrosser. It doesn’t have every new feature available. There’s no seat on top of the gas tank.
That same lack of excitement carries over to riding the RM 125. Start it up and let it warm up for five or six minutes, to make sure it doesn’t cold seize, then snick it in gear and take off. Unless you're heavy, 2nd gear starts work fine. A bigger rider might start out in 1st and shift into 2nd as soon as the bike clears the starting gate. From that point the rider has to shift sooner than he expects. That’s the way the RM 125 runs. Ridden like last year’s RM 125 the new bike just buzzes and goes slowly. Short-shifting as quickly as possible, an RM 125 rider can stay with the middle of the pack against other stock 125s.
On a muddy track the greater flywheel and mid-range punch help the Suzuki work better. In any other conditions this new bike is slower than the 1982 RM 125 and slower yet than the 1981 RM 125. Of course in the Pro classes all the bikes are ported anyway, and the Suzuki has as much potential for porting as any of the other 125s. For novice riders or just playbike use, the wider powerband works.
SUZUKI
RM125
$1739
For any rider the Suzuki’s suspension is a dazzler. The adjustable forks are as good as any made, and Suzuki’s rear suspension has somehow managed to work better than any other rear suspension for the last couple of years. It still does. Jumping off killer cliffs the rider never gets jarred and the bike never makes those crashing or clanging noises. Genuinely crazy riders love the Full-Floater Suzukis because they don’t spend so much time healing. The Suzuki can be ridden over craters sitting down, in full control.
Handling is stable and secure, but not as quick as some bikes. The kicked-out 29.5° rake and 4.7 in. of trail slow down the steering. Turning on hard ground requires moving way up on that unpadded gas tank or the front tire will skate. Changing the stock IRC front tire to a Dunlop K139, Metzeler or Bridgestone M32 cures most of the skating as long as the rider doesn’t get sloppy and go blasting into the turn with his butt too far back on the seat.
Pro-level riders, now used to double leading shoe front brakes and disc brakes, thought the Suzuki’s front brake too tame. Slower riders didn’t notice it.
With three years now given to development of the RM 125, Suzuki hasn’t built a faster, or lighter bike. This year it weighs 205 lb., 8 lb. more than it did last year. The power is down, too, which doesn’t help matters. It’s still an enjoyable bike to ride, and ours was as reliable as tomorrow. In several races and other rides it never failed to start and run fine. Maintenance amounted to chain adjustments and cleaning the double foam air filters, which takes more time than it should.
The RM 125 isn’t going to win the race to the first turn or dazzle your friends with looks or technology. Instead, it’s a competitive bike that can be turned into as good a racer as any, provided a little engine work is done.The chassis is there.®
