That information and Review Suzuki DR-Z 400SM :
ISAAC NEWTON WOULD have approved. it had been Sir Isaac’s Second Law of Motion: Force = Mass x Acceleration, that firstexplained the link between an object’s weight and the way that might have an effect on its dynamic behavior. In fact, you may decision
Newton the godfather of Power/Weight Ratio-based performance, and Lotus’ Colin Chapman his greatest disciple. And no street-legal bike illustrates the physics higher than the DR-Z400SM.
Based on the highly regarded DR-Z400S dual-sport, obsessive calorie counting has resulted in a very full-up wet weight of simply 318.5 lbs,
pushed by thirty three.4 horsepower measured at the rear wheel. It doesn’t sound like enough to be exciting, however it most actually is.
The SM designation stands for Super-Moto, the most recent competition craze, whereby light-weight four-stroke motocross bikes are
modified with huge brakes and 17-inch wheels to race on combination dirt and asphalt race courses. The concept goes back to the
“Superbikers” a made-for-TV event that ran on ABC’s Wide World Of Sports from 1979 to 1985, that pitted proficient motorcyclists
from all disciplines against each other on individually changed, run-what-ya-brung bikes. the thought seemed to die out when the TV
series expired, however was resurrected by the French some years ago, and has since proved very hip in Europe with a growing following in America. though serious competition machines are created for the category by KTM, Husqvarna and others, the
new Suzuki is that the initial Japanese super-moto to be sold in America, and is totally street legal as delivered, in contrast to a number of the eu models. Its arrival in Suzuki’s US warehouses has been largely unheralded, as if the corporate wished to check the waters before committing serious advertising bucks. however we’re here to inform you that if you prefer minimalist machines, you’ll adore the Suzuki DR-Z400SM.
It’s not necessary to think about the SM as simply a contest bike with lights, as a result of because the Europeans have found, the supermoto additionally makes an ideal urban assault vehicle, most likely quicker from purpose A to purpose B in densely populated cities than simply concerning the other bike, in addition as a terrific sportbike where rougher and poorly kept roads predominate.
THE MOTOR
If you were disappointed that the most recent 450cc MX engine wasn’t chosen to power the bike, take into account that every one the state-of-the-art fourstroke motocross engines are terribly highly stressed and maintenance intensive. They additionally weren’t designed to pass emissions or the sturdiness cycles needed for compliance.
The DR400S motor was. And it’s no slouch either. With a bore of stroke of 90mm x sixty two.6mm, it'll rev a lot of above larger displacement singles, hitting the rev limiter at 9750 rpm. keep in mind that an engine’s rev vary is an under-appreciated live of its true performance.
When 2 engines create constant horsepower, however one revs five hundredth higher, the world beneath the ability curve is far larger for the
higher-revving motor, and quarter-mile times keep a copy the importance of the distinction. Counterbalanced so it's terribly swish
running, it won’t try and shed nuts and bolts at high revs or tire the rider.
To achieve thirty three.4 hp from twenty four.3 cubic inches (398cc) the engine uses twin overhead cams to work four terribly massive
valves; pairs of 36mm intakes and 29mm exhausts, surrounding a centrally located spark plug for fast, economical combustion. The piston may be a solid slipper sort, to cut back reciprocating weight by a minimum of 100 percent over a a lot of
conventional solid slug.
The piston’s high ring is an upscale L-section Dykes-type, that reduces emissions by reducing trapped fuel whereas it improves sealing potency. The aluminum cylinder uses no iron liner, however instead is plated with Suzuki’s proprietary nickel-silicon-phosphorus-carbide (SECM) material to boost heat transfer and scale back engine weight. and eventually, the fuel enters via a giant 36mm Mikuni CV carb.
Although it may little question be tuned to form even a lot of power, as delivered it provides a broad torque curve that produces a harmonious match for the machine’s weight and five-speed transmission. the general result may be a swish steady flow that’s simple to modulate.
Liquid-cooled for potency, a thermostatically controlled fan can have interaction in slow traffic to keep up airflow. Otherwise, the large air-scoops, sized for slower happening dirt, can direct lots of airflow over the slim radiators on either aspect.
The transmission shifts simply and therefore the ratio unfold has been puzzled out to optimize pull between gears. though we might have welcomed a sixth gear, we have a tendency to were glad with 5. (Note that the motocross four-strokes typically have solely four gears.) The clutch
is cable operated, the pull is lightweight and therefore the engagement vary is wide enough to form it simple to slide exactly.
Fuel potency is another profit obtained from Newton’s Second Law, and that we achieved nearly forty five mpg on average, riding enthusiastically. though we have a tendency to never tried riding for fuel potency, we’d guess fifty mpg would are attainable.
An electric starter is fitted and therefore the engine options an automatic decompression device to ease beginning effort. A choke button is fitted to the aspect of the carb and is critical whenever the engine’s even moderately cold. when a second or therefore, it'll be heat enough to run while not the additional enrichment.
ROLLING CHASSIS
Similar in style to Suzuki’s motocross bikes, the SM’s chassis may be a light-weight chromoly steel construction with the engine oil contained within the backbone and front downtube, so the engine are often a dry-sump style, so as to stay the engine’s weight low within the frame. A bash plate protects the crankcase, however with nearly a foot of ground clearance, it shouldn’t get scratched on pavement or perhaps dirt roads.
The light-weight plastic aspect panels are hooked up with D-ring Dzus fasteners, so you have got quick access to the air filter or battery.
Incidentally, the battery may be a compact 12V/10Amp/Hr unit and resides beneath the left variety panel opposite the muffler, where it's
both high and low-speed compression damping, one thing you sometimes solely notice on high-end motocross equipment or expensive
road-racing shocks. a distant reservoir sort for fade resistance, it's additionally rebound and preload adjustable.
The rear travel is ten.9".
However, even with the marginally soft front springs, this can be exceptional suspension and therefore the ride is terrific, Barcalounger plush nevertheless
with nice management and feedback, once more because of the machine’s lightweight weight. apart from the non-adjustable front preload, we have a tendency to couldn’t
think of any thanks to improve it.
Brakes are a section where super-motos depart sharply from their dirt-bike counterparts and therefore the equipment on the SM is once more distinctive.
The front disc may be a huge 310mm unit that’s each skinny in radial section and heavily drilled to cut back its weight any. Even some holes in a very brake disc will increase its potency, because the gasses that otherwise build up between the pad and disc are often evacuated and any debris that may tend to induce caught and score the disc or pads will sometimes exit before doing harm.
The front caliper may be a two-piston, singleaction sort, lighter than a four-piston unit would be. along they produce powerful stopping force however are never grabby, creating them ideal for smart management on slippery surfaces in addition nearly as good pavement. The rear brake is another Swiss-cheesed disc, this one among 240mm, slowed by one piston caliper. we have a tendency to were impressed with the rear brake’s slowing power in addition as how simple it had been to avoid sliding
the rear tire.
The wheels are what very establish a super-moto. The enduro bike’s light-weight hubs are laced to wide 17-inch black-anodized
aluminum hoops in three.50 and 4.50 widths front and back. and therefore the tires are special, too, H-rated Dunlop Sportmax 208-compound radials in 120/70 front and 140/70 rear sizes. The pressures specified are simply twenty five psi front and twenty nine back (solo, or thirty three psi rear with a passenger).
These things get noticeably hot and tacky in traditional use and stick like
glue to the turns. If they weren’t fitted to a motorbike just like the SM, they
probably wouldn’t last terribly long.
RIDING IMPRESSION
Initially, the bike feels impossibly tall and short, and that we puzzled
how it may handle securely with such an extreme layout. It took a
while to regulate, however alter we have a tendency to did. the primary factor we have a tendency to learned was to
be as swish as attainable. In fact, therefore very little body movement is critical,
unless speeds were terribly high, we’d simply lean the bike beneath us,
like you would a mud bike.
Of course, there was never a desire to conserve lean angle with the high ground clearance and slender footpegs. If the bike felt blown around an excessive amount of on the freeway, we’d simply hug the tank with our knees, so we might be less possible to over-control the handlebars.
The approach the bike are often balanced with the rider’s weight is another rare treat. Sitting within the center of the bike, you may simply influence that finish got a lot of grip as you shifted the load of your torso front and back. On twisty roads, the bike’s bottomless suspension insures that tires keep in constant contact with the road, and even on very rough ground that might get the other bike airborne, the SM stayed securely planted. Even higher is that the exquisite accuracy of the steering, enabling you to put the bike exactly where you wish for optimum traction.
During testing, the sole limit to our tested stopping distances was the tendency to nose-stand (stoppie), which was
aggravated by the softish fork springs and high Center of Gravity.
The carbureted engine may be a model of swish management, never abrupt, and provides surprisingly adequate performance. solely in high-speed passing may we've asked for a lot of horsepower. (However, all the aftermarket goodies created for the favored DR-Z400S enduro can bolt right on.)
INSTRUMENT/CONTROLS
Like the enduro model, the SM gets a trick digital instrument cluster with a bright speedo, dual trips, odometer, clock and even a
stopwatch. Subtraction functions are accessible on the visits and stopwatch in addition. However, there's no tachometer, and you’d most likely be freaked if there have been. the tiny engine wails to stay your pace high, turning 6170 rpm (calculated) @ sixty five mph and 7595 @ eighty mph in high gear, however doesn’t protest. In fact, the valve adjustment interval, 14,500 miles, suggests it'll rev like this all day while not frequent maintenance.
Also, each the shifter and brake pedal have folding tips, a neat feature for hard-core use and therefore the handlebars are braced for smart live. However, the sore spot within the package, the seat, can cause you to assume the SM stands for sado-masochism.
A towel over a two-byfour would be as soft. Worse, the highest of the seat is therefore slender that it fits between the bony rails of the pelvis, like some perverse wedgie. If you didn’t have hemorrhoids before, you'll if you don’t fix it. Thankfully, we've an Air-Hawk pad stashed for such occasions. Without it, fifty miles would are too so much, with it, we have a tendency to had an unpleasant seat we have a tendency to may ride all day. a minimum of upholstery may be a low-cost fix, as fixes go. What were they thinking?
BOTTOM LINE
To give Suzuki credit, not solely are they the primary Japanese company within the game stateside, however their machine is probably a purer expression of the concept than the street-legal 650cc supermotos that are accessible overseas from Honda and Yamaha. The SM’s motor makes a lot of power per cubic in. and is in a very a lot of lighter chassis than the bigger-bore machines. There won’t be lots to travel around, so, if you wish one, don’t wait.
