
Like Rodney Dangerfield, playbikes don't get no respect. They get little
publicity hype from the manufacturers and only mild attention from the
general public. Usually manufacturers equip playbikes with designs, if not
components, that were the latest and greatest a few years earlier. As a
result, playbikes always seem two steps behind in both fashion and function.
So what, you may say. Playbikes are intended for fun, not serious
competition. Well, what's fun about pushing your bike up a loose, rocky
uphill because the engine doesn't crank out enough power to pull you up? And
what's fun about getting tossed on your ear because your bike doesn't handle
well? Beginning riders in particular need all the help they can get from
their machines. To survive in the sport long enough to graduate to a
"serious" off-road bike, a budding dirt rider needs to begin his riding
career with a good off-road mount.
Apparently Suzuki agrees: their brand-new DR250Z is a product of a
serious effort to produce a better-than-average playbike, and that's good
news for advanced as well as non-expert off-road riders. The factory
injected Suzuki's latest technology into the DR250 chassis and engine: among
other things, the powerplant carries Suzuki's Twin Swirl Combustion Chamber
(TSCC) cylinder head, and the running gear features the Full Floater rear
suspension system. As a result, the new mid-sized four-banger works notably
well for a first-year effort.
The DR engine displaces an actual 249cc by means of a 72.0mm bore and a
61.2mm stroke; the short-stroke Honda XR250, in comparison, measures 74.0mm
by 57.8mm. Like most of Suzuki's newly designed four-stroke engines, the
DR250 powerplant is centered around the TSCC cylinder head. The patented
TSCC head's four-valve design improves intake charging efficiency compared
to a two-poppet setup, while the combustion chamber shape promotes a
swirling action claimed to improve throttle response, increase power, and
provide cleaner combustion through improved fuel-mixture burning efficiency.
The 26mm intake valves and 22mm exhaust valves are set at a fairly narrow
included valve angle, which helps smooth intake tract flow, and the piston
has a flat-topped dome with modest valve-pocket cutouts.
Since it actuates the four valves through forked rocker arms, the single
overhead camshaft has only two cam lobes. The rockers feature screw-type
adjusters which let home mechanics tinker with valve adjustment. Access,
though, is tight: the front downtube crowds the exhaust-side adjusters, and
you must remove the fuel tank to get to the intake-side adjusters. A durable
Hy-Vo-type chain drives the camshaft, and an automatic chain tensioner
eliminates maintenance worries.
Feeding the engine is a 28mm Mikuni slide-type carburetor. It takes
minimal effort to reach the oiled foam air filter element for servicing,
which makes this messy but necessary chore a little less odious. The exhaust
gases exit through individual head pipes which are upswept and join an
effective muffler /spark arrestor approved for use in National Forests.
A gear-driven counterbalancing system, in an unusual location, combats
excessive vibration in the 250 thumper. The balancer shaft is situated above
and behind the crankshaft axis (which is not unusual), but the entire
balancer, drive gear and driven gear are all located within the center
cases. Most balancer-equipped engines house the drive gears in one of the
side cases. The DR250's setup, in contrast, is particularly narrow and tidy.
The drive gear sits immediately to the right of the right-side flywheel, and
the balancer weight rotates between the two crank flywheels. The balancer
driven gear has six damper springs that ease shock loads in the balancer
system.
The ignition rotor spins on the left end of the crankshaft; the cam drive
and primary drive gears are located on the right end. The DR uses
helical-cut primary gears (much quieter than straight-cut gears, albeit
slightly less efficient). Power passes through a multiplate wet clutch to
the five-speed transmission, and from there to the rear wheel via a 520
final-drive chain.
A manually operated engine de-compressor eases the 250's starting drill,
though this system is less convenient than Honda's and Yamaha's automatic,
kickstarter-activated compression-release systems. The Suzuki owner's manual
divides the starting procedure into three steps. First, squeeze the
handlebar-mounted lever. This activates the decompression mechanism, which
cracks the exhaust valves open just enough to let the engine pass top dead
center easily. Next, slowly stroke the kickstart lever through until the
decompressor lever returns to the "home" position. The piston is now past
TDC. Finally, give a stout full-stroke kick to the start lever to light the
engine off. If the decompression lever can be pulled in with no resistance
and returns to the home position when released, the piston is past TDC and
need not be eased over. Just kick away.
We used the starter decompressor primarily when the engine was cold; the
DR takes up to six kicks to light off when cold but starts readily with or
without the decompressor after the engine has warmed. After a moderate
warm-up period, the 250 carburets cleanly, and the throttle response is free
of glitches or hesitations. A useful amount of torque covers a wide range of
engine speeds; the 250 will lug way down low and still rev out willingly,
although the engine feels flat on the top end. Overall, the 250 engine has a
friendly nature; the wide power spread and abundant flywheel effect make the
DR extremely tractable and easy to ride. The 250 shines on loose uphills or
tight, snotty trails; the bike keeps plonking forward, demanding little from
the rider.
"Extremely tractable" doesn't mean that the DR250 is a horsepower demon.
Quite to the contrary, its peak output of 16.76 horsepower puts it squarely
at the back of the pack in the 250 four-stroke class, and on par with the
Honda XR200R. Two-stroke enduro and MX 250s regularly pump out 30 to 35
ponies, which really puts things into perspective.
In some situations 17 horses simply aren't enough. For example, it can be
difficult to keep the front end light over a long set of whoops, and on
wide-open desert trails and fast fireroads the DR feels strained. While 250
four-strokes in general suffer a dearth of horsepower, the DR's lack of
power is especially acute; playbike-type riders may not object, but more
serious off-road competitors will be tempted to explore other options.
Although the Suzuki's five gearbox ratios match the engine
characteristics nicely, the DR doesn't shift well with or without the
clutch. Shift action is balky and we missed more than a few gear changes.
The clutch fades with heavy use, and doesn't disengage cleanly when hot,
even when readjusted.
Granted, the fat powerband obviates clutchwork some of the time, but for
real tight, rough work the clutch just isn't up to snuff.
Thanks to an up-to-date chassis, the Suzuki handles better than the
average playbike. Although the DR's Full Floater rear suspension system
differs slightly from the Full Floaters found on the RM-series motocrossers,
the design and basic layout remain unchanged. Suzuki changed the lengths of
various linkage pieces, the materials, and the location of some of the pivot
points to accommodate the play-bike's decreased travel. For example, Suzuki
replaced the aluminum upper rocker found on the MX bikes with the DR's steel
rocker. The shock, however, is still compressed at both ends, the swing arm
is a box-section, RM-like aluminum item, and the linkage provides a
rising-rate effect.
The aluminum-bodied shock itself is nitrogen-charged, and it has a remote
reservoir and four-way adjustable rebound damping—all features carried over
from the RM dampers. Naturally, Suzuki altered the shock valving to suit the
DR's weight, suspension travel, and projected use. As with the motocrossers,
you can replace the DR's shock oil when it begins to break down. Also, like
the motocrossers, the DR's shock spring uses threaded adjusters for preload
adjustment; the dual-purpose SP250 features a ramped collar with only seven
possible settings. The DR provides 9.5 inches of rear-wheel travel—plenty by
playbike standards.
The 250's fork is derived from past RM-series bikes; the fork tubes are
36mm in diameter, in contrast to the 38-42mm fork tubes used by most
competition bikes. The springing and damping rates are unique to the DR, and
the fork provides 9.6 inches of well-damped front-wheel travel. Separate air
caps come as standard equipment on the 250. Suzuki, though, recommends
running the bike with zero psi in the fork. We liked the DR with nine pounds
of air up front and the shock damper on the number three position.
Riding the DR250 causes something of a revelation. Although the 261-pound
Suzuki can't be called a featherweight, it is light compared with the Honda
250 thumper, which weighs about 20 pounds more. For the record, two-stroke
MX bikes run from about 230 to 240 pounds with one gallon of gas, and
Yamaha's two-stroke 11250 enduro bike weighs about 245 pounds. The DR feels
tight and compact, if not light, and it's comfortable to ride sitting down
or standing up. The lowish 35.5-inch seat height puts the novice at ease,
but the DR still has a useful 13.2 inches of ground clearance available and
footpegs a relatively safe 14.5 inches off the ground.
The DR steers precisely, and you're free to choose the tight inside line
or slide around the outside; the front end sticks nicely and resists pushing
the front wheel. Considering its modest 55.9-inch wheelbase, the 250 works
remarkably well in sand and it keeps tracking dead ahead through deep
whoops; although the rear end kicks out a few inches to either side, the
bike never side-hops alarmingly. Off jumps, however, the rear end bottoms
too easily and we felt a noticeable amount of fork flex. A slightly heavier
shock spring or more progressive shock action and the full-on 38mm Suzuki
fork would be welcome additions.
The 250cc powerplant can withstand frequent water crossings, but the
brakes fare less well. Both ends take quite a while to come back after a
thorough soaking, and neither works especially well even under the best
conditions: the front brake feels spongy and needs more stopping power; the
rear brake is overly sensitive
Small but nice touches abound on the DR250. A rugged PE-style odometer is
resettable forward and backward by tenths; a six-volt, 15-watt headlight
will light your way back to camp after dark; the rear fender is mounted on a
grab bar that provides plenty of purchase when you have to horse the bike
around by hand (far too many off-road mounts lack a grab spot at the rear of
the bike); the engine offers a primary kickstart feature should you stall
the bike in an awkward place; and the tool kit is stowed in a small, readily
accessible compartment behind the front number plate.
The filler neck of the gas tank is plenty wide, which makes refueling the
bike easy. However, we question the wisdom of using a steel fuel tank; the
tank will look like a relic of the Boer War after a few minor get-offs. The
SP and DR apparently share tanks as an economy move, but while steel tanks
are necessary for street-going bikes, off-road machines do better with
plastic tanks. The DR's 2.5-gallon fuel capacity takes the 250 about 60 or
70 miles before it runs dry.
With the DR250Z, Suzuki offers front-line features in a class formerly
filled with second-string equipment—and their bike is a viable alternative
to the class favorite, the Honda XR250R. The DR is substantially down on
power compared to the XR, and power equals fun most of the time, but at
least part of that difference is offset by a savings in weight. Even though
the Suzuki's fork is not quite as good as the Honda's front end, the 250's
Full Floater rear suspension system is a bit better than the XR's Pro-Link
rear end.
But the most significant difference between the two bikes is cost; at
$1598, the Suzuki will leave your wallet $250 fuller than will the Honda XR.
Serious competitors may be tempted to go with the Honda's extra horsepower,
but smart shoppers in the market for a playbike/ semi-serious enduro bike
may find these savings hard to ignore
Source Cycle Magazine